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  • Restoration of the Paleocene-Miocene nautiloid cephalopod Aturia
  • Fossilized fronds of the Carboniferous-Early Cretaceous seed fern Alethopteris
  • Fossils of the Ordovician-Permian bryozoan Amplexopora
  • Fossil of the Carboniferous horsetail relative Annularia
  • Fossil of the Carboniferous horsetail relative Annularia
  • Restoration of the face of the Carboniferous reptiliomorph Anthracosaurus
Illustration of Anthracosaurus fossils including a skull pictured from above (left), a cross section of a tooth (upper right), and tooth itself (lower right)
  • Restoration of the Carboniferous synapsid (mammal precursor) Archaeothyris
  • Restoration of the Carboniferous synapsid (mammal precursor) Archaeothyris
  • Reconstructed cranium of the Carboniferous synapsid (mammal precursor) Archaeothyris
  • Fossil of the Silurian trilobite Arctinurus
  • Fossilized shell of the Silurian-Late Devonian brachiopod Atrypa reticularis
  • Mold fossil of a shell of the Early Devonian-Late Triassic bivalve Aviculopecten
  • Fossil of the Late Ordovician-Permian tabulate coral Aulopora
  • Fossilized shell of the Early Cretaceous-Oligocene turtle Adocus
  • Restoration of the Cretaceous-Pleistocene amphibian Albanerpeton
  • Fossilized skeleton of the tyrannosaur Albertosaurus
Restoration of the Late Jurassic theropod dinosaur Allosaurus
  • Fossilized skull of the Late Jurassic crocodile relative Amphicotylus
  • Fossil (right) of the Early Jurassic dinosaur footprint ichnogenus Anomoepus
  • Upper view of the pelvis of the Late Jurassic sauropod dinosaur Atlantosaurus. This genus is now regarded as being of dubious validity and possibly the same as Apatosaurus.
  • Fossilized shell of the Late Ordovician-Carboniferous brachiopod Atrypa
  • A living Acteon barrel bubble sea snail
  • Fossilized shell of the Late Cretaceous oyster Agerostrea
  • Illustration of a living Albula bonefish
  • Fossilized shell of the Jurassic-Miocene sea snail Ampullina
  • Interior and exterior of a shell of an Anomia, or jingle shell
  • Fossilized skull and skeleton of the Late Cretaceous primitive tyrannosaur Appalachiosaurus
  • Restoration of the Late Cretaceous primitive tyrannosaur Appalachiosaurus
  • A living Architectonica staircase shell sea snail
  • Fossil of the Late Cretaceous crab Avitelmessus
  • Multiple views of a fossilized shell of the volute sea snail Athleta
  • Shell of an Atrina pen shell
  • Fossil of the Silurian-Middle Devonian trilobite Acanthopyge
  • Fossilized shell of the Middle Devonian ammonoid cephalopod, Agoniatites
  • Fossilized shells of the Early-Late Cretaceous marine bivalve Actinoceramus
  • Restoration of the Late Cretaceous dome-headed dinosaur Alaskacephale and inset diagram depicting it with an anachronistic human to scale
  • Fossilized shell of the Early Jurassic ammonoid cephalopod Amaltheus
  • Fossilized shell of the Carboniferous-modern scallop Amusium
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Anapachydiscus
  • Restoration of two species of the Late Triassic ammonoid cephalopod Arcestes
  • Fossilized shell and spines of the Late Devonian-Permian sea urchin Archaeocidaris
  • Fossilized shells of the Middle Jurassic ammonoid cephalopod Arcticoceras
  • Fossilized shell of the Early Jurassic ammonoid cephalopod Arnioceras
  • A living Alces, or moose
  • A living Alnus, or alder tree
  • A living Vulpes lagopus, or arctic fox
  • Restoration of the Oligocene river dolphin Arktocara
  • Fossilized shell of the Paleocene-Miocene nautiloid cephalopod Aturia
  • Fossilized plates and spines of the Late Devonian-Permian sea urchin Archaeocidaris
  • Fossils of the Carboniferous-Permian bryozoan Archimedes
  • Stereogram of a fossil of the Carboniferous-Permian bryozoan Archimedes
  • Fossilized shell of the Early Cretaceous ammonoid cephalopod Acanthohoplites
  • Fossilized shell and skull of Glyptops (left and center) and the shell of Adocus
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Allocrioceras
  • Restoration of the Late Triassic phytosaur Angistorhinus
  • Restoration of the Late Jurassic sauropod dinosaur Apatosaurus
  • Petrified trunk segments of the Permian-Late Triassic conifer tree Araucarioxylon arizonicum
  • Restorations of various Chinle Formation fishes, including the Late Triassic lungfish Arganodus (bottom)
  • Restoration of the Late Triassic lungfish Arganodus with an anachronistic human to scale


Fossils of the mysterious Ediacaran organism Aspidella
Fossil of the mysterious Ediacaran organism Aspidella
Fossils of the mysterious Ediacaran organism Aspidella
Diagram depicting the soft part anatomy of the sea snail Abyssochrysos
Fossilized teeth of the Permian-Paleocene cartilaginous fish Acrodus
Restoration of the Late Cretaceous armored dinosaur Aletopelta
Shell of an Amauropsis moon sea snail
Shell of an Architectonica staircase shell sea snail
Shell of an Architectonica staircase shell sea snail
Fossilized shell in multiple views of an Architectonica staircase shell sea snail
Rear side of a fossilized shell of the Late Cretaceous-modern brachiopod Argyrotheca
Illustration of a larva of the Late Cretaceous-modern brachiopod Argyrotheca
Fossilized shell of the Early Jurassic ammonoid cephalopod Asteroceras
Fossilized partial skull of the Late Cretaceous duck-billed dinosaur Augustynolophus
Illustration of a living Acipenser medirostris, or green sturgeon
A living Acmaea mitra, or whitecap limpet
Fossilized skeleton of the Miocene horse Acritohippus
A living Actinemys marmorata, or western pond turtle
A living Aechmophorus occidentalis, or western grebe
Fossilized skull of the Miocene bone-crushing dog Aelurodon
Restoration of the Miocene camel Aepycamelus, or the long-necked camel. Heinrich Harder (1920).
Fossilized shell of the Triassic-modern scallop Aequipecten
A living Agelaius
Foliage and fruits of an Ailanthus tree
Restorative model of the Miocene deer relative Aletomeryx
Caught Alopias vulpinus, or common thresher
Shells in multiple views of Alvania sea snails
Illustration of a shell of Amauropsis moon sea snails
Flowers and foliage of Amelanchier, or shadbush
Close-up view of the flowers of Amorpha fruticosa, or desert false indigo
Restoration of the Miocene-Pliocene beardog Amphicyon
Collection of Anadara marine ark clams
A living Mareca americana (formerly Anas americana), or American wigeon
A living Spatula clypeata, or northern shoveler
Fossilized limb bones, and teeth of the Miocene three-toed horse Anchitherium (left)
A living Anniella, or American legless lizard
A living Anser albifrons, or greater white-fronted goose
A living Antilocapra, or pronghorn
A colony of roosting Antrozous pallidus, or pallid bats
A living Aphelocoma californica, or California scrub jay
Reconstructed skeleton of the Miocene-Pleistocene hornless rhinoceros Aphelops
A living Aquila chrysaetos, or golden eagle
Branch with foliage and fruit of a living Arbutus, or madrona
Fossilized skull of the Oligocene bone-crushing dog Archaeocyon
Illustration of a living Archoplites interruptus, or Sacramento perch
Living Arctocephalus fur seals
Shells of Argopecten gibbus, or Atlantic calico scallops
A modern Argyropelecus silver hatchetfish
A living Asio otus, or long-eared owl
A living Astropecten sea star
A living Athene cunicularia, or burrowing owl
Fossilized skull of the Miocene dolphin Atocetus
Restoration of the Miocene sperm whale Aulophyseter
Restoration of the Middle-Late Ordovician jawless fish Astraspis
A living Abies, or fir tree
A living Acalles weevil
A living Acris, or cricket frog
Living Acrostichum, or leather ferns
A living Agrilus jewel beetle
A living Agriotes click beetle
Branches and fruits of an Aleurites tree
Restoration of the crocodilian Allognathosuchus
A living Altica flea beetle
A living Amblyteles parasitic wasp
Restoration of the Miocene elephant relative Amebelodon. Margret Flinsch (1932).
A living Anabrus , or Mormon cricket
Fossilized limb bones, jaws and teeth of the Miocene three-toed horse Merychippus (left)
A living Andrias giant salamander
Fossilized tooth of the Oligocene-Miocene shark Carcharocles angustidens
A living Anthaxia jewel beetle
A living Anthidium, or carder bee
A living Anthomyia fly
A living Anthonomus weevil
Fossil of the Eocene ant Aphaenogaster mayri
A living Aphodius scarab beetle
A living Aphrophora spittlebug
A living Araneus orb-weaving spider
Restoration of the Eocene-Oligocene entelodont mammal Archaeotherium
Fossil of the Eocene ant Archimyrmex
Restoration of the Paleocene mammal Arctocyon
A living Argia damselfly
Flower of a living Aristolochia, or birthwort
Fruit and foliage of an Asimina tree, or pawpaw
A living Astronium tree, which is related to cashews
A living Athous click beetle
A living Aythya americana, or redhead
Fossilized teeth of the Pliocene-Pleistocene rabbit relative Aztlanolagus
Restoration of the Early Jurassic sauropodomorph dinosaur Anchisaurus
Fossilized skeleton of the Late Cretaceous bony fish Apsopelix
Fossilized mandibles of the Miocene three-toed horse Anchitherium
Closed and open shell of Abra marine bivalves
Living Acropora cervicornis, or staghorn coral
Shells of Acteocina barrel-bubble sea snails
A living Actitis macularius, or spotted sandpiper
A living Aetobatus narinari, or spotted eagle ray
A living Agelaius phoeniceus, or red-winged blackbird
Close-up portrait of a living Agkistrodon piscivorus, also known as a water moccasin or cottonmouth
A living Aix sponsa, or wood duck
A living Platalea ajaja (sometimes Ajaja ajaja), or roseate spoonbill
A living Alligator mississippiensis, or American alligator
Living Alveopora stony coral
A living Amia, or bowfin
A living Ammodramus maritima, or seaside sparrow
A living Amphiuma means, or two-toed amphiuma
Shell of an Anachis dove sea snail
Shell of an Anadara floridana, or cut-ribbed ark clam
Shell of an Anadara transversa, or transverse ark clam
A living Anas carolinensis, or green-winged teal
A living Spatula cyanoptera, or cinnamon teal
A living Anas rubripes, or American black duck
A living Anhinga, also known as a snakebird or darter
Shell of an Anodonta river mussel
Shell of an Anomia simplex, or the common jingle shell
Shell of an Antillophos nassa mud snail
A living Apalone ferox, or Florida softshell turtle
A living Aphelocoma coerulescens, or Florida scrub jay
A living Arbacia sea urchin
Interior of the shell of an Arca zebra, or turkey wing ark clam
A living Archosargus probatocephalus, or sheepshead
Shells of Arcinella arcinella, or Caribbean spiny jewel box clams
A living Ardea herodias, or great blue heron
A living Ardeola, or pond heron
A living Argopecten irradians (formerly Aequipecten irradians), or Atlantic bay scallop
A living Asio flammeus, or Short-eared owl
Shell of an Assiminea snail
Shell in multiple views of an Astralium, or star sea snail
Shell of a Lithopoma phoebium (formerly Astraea phoebia), or longspine star shell sea snail, inhabited by a hermit crab
Fossil of the Cambrian trilobite Asaphiscus
Restoration of the Late Cretaceous tyrannosaur Albertosaurus
Interior of the shell of an Arca ark clam
A living Amphiuma
Shell in multiple views of an Anadara brasiliana, or incongruous ark clam
Electron micrograph and gross view of an Astrangia poculata stony coral
Assemblage of fossils of the Cambrian trilobite Agnostus
Restoration in enrolled posture of the Cambrian trilobite Agnostus
Living Abies, or fir trees
Fossilized fronds of the Carboniferous-Early Cretaceous seed fern Alethopteris
Restoration of the Carboniferous amphibian Amphibamus
Illustration of a fossil of the Carboniferous pill millipede Amynilyspes
Fossilized foliage of the Late Devonian-Carboniferous tree Archaeopteris
Restoration of the Late Devonian-Carboniferous tree Archaeopteris with insets detailing its anatomy
Restored foliage of the Late Devonian-Carboniferous tree Archaeopteris
Illustration of a fossil of the Carboniferous-Permian spider Arthrolycosa. Charles Emerson Beecher (1889).
Fossilized calyx of the Carboniferous crinoid ("sea lily") Abrotocrinus
Fossilized calyx and partial stem of the Devonian-Permian crinoid ("sea lily") Actinocrinites
Fossilized calyx and partial stem of the Carboniferous crinoid ("sea lily") Agaricocrinus
Fossilized calyx of the Carboniferous crinoid ("sea lily") Agaricocrinus americanus, or the mushroom crinoid
Fossilized stem of the Carboniferous crinoid ("sea lily") Agaricocrinus americanus, or the mushroom crinoid
Life restoration of the Early Devonian club moss relative Asteroxylon
Restoration of the Early Devonian-Permian "spiny shark" Acanthodes
Fossilized skeleton of the Early Devonian-Permian "spiny shark" Acanthodes
Life restoration of the Carboniferous synapsid (mammal precursor) Archaeovenator
Fossilized shell of the Late Cretaceous ammonoid cephalopod Acanthoscaphites
Illustration of a partial fossilized pelvis of the Late Cretaceous bird Apatornis
A living Anaxyrus cognatus (formerly Bufo cognatus), or Great Plains toad
Fossilized dorsal fin-spine of the Devonian-Cretaceous shark Asteracanthus
Fossilized teeth of the Devonian-Cretaceous shark Asteracanthus
Shells of Acirsa wentletrap sea snails
A living Ammospermophilus, or antelope squirrel
A living Ariosoma conger eel
Life restoration of the Early Cretaceous theropod dinosaur Acrocanthosaurus
Fossilized skeleton of the Late Cretaceous-Oligocene Alligator relative Allognathosuchus
Assemblage of fossilized skeletons of the softshell turtle Amyda
Restoration of the Early Cretaceous sauropod dinosaur Astrodon
Illustration of a living Acipenser sturgeon
Living Acropora palmata, or elkhorn coral
Fossilized skull of the Miocene baleen whale Aglaocetus
A living Asterias forbesi, or Forbes sea star
Restoration of the Miocene stargazer Astroscopus countermani
Fossil of the Cambrian trilobite Agraulos
Diagram illustrating the Early Jurassic sauropodomorph dinosaur Anchisaurus with an anachronistic human to scale
A living Abies balsamea, or balsam fir
Fossilized skeleton of the gar Atractosteus
Restoration of the Late Ordovician nautiloid cephalopod Aphetoceras being preyed upon by a Cameroceras
Fossilized skeleton of the Carboniferous lobe-finned fish Allenypterus
Restoration of the Carboniferous lobe-finned fish Allenypterus
Restoration of the Late Cretaceous horned dinosaur Achelousaurus
Restoration of the Late Cretaceous dromaeosaurid ("raptor") Acheroraptor
Fossilized skull of the Late Cretaceous duck-billed dinosaur Acristavus
Restoration of the Late Cretaceous horned dinosaur Albertaceratops
Restorative model of the Late Cretaceous mammal Alphadon
Image of restored specimen of a squat quadruped with knobby back
Restoration of the Late Cretaceous armored dinosaur Ankylosaurus
Restoration of the Early Cretaceous primitive horned dinosaur Aquilops
Restoration of the Late Cretaceous horned dinosaur Avaceratops
Restoration of the Late Cretaceous toothed bird Avisaurus perched on a crocodilian
Life restoration of the Eocene-Oligocene even-toed ungulate Agriochoerus
Living Araucaria trees
Living Azolla water ferns
Illustration of a living Aplodinotus grunniens, or freshwater drum
Diagram of a restored biramous leg of the Cambrian trilobite Agnostus
Fossil of the Cambrian arthropod Anomalocaris
Restoration of the Cambrian arthropod Anomalocaris
Diagram illustrating the Cambrian arthropod Anomalocaris with an anachronistic human to scale
Fossilized grasping claw of the Cambrian arthropod Anomalocaris
Restorative model of the Cambrian arthropod Anomalocaris
Fossilized mouthpart of the Cambrian arthropod Anomalocaris
Fossilized shell of the Early Jurassic ammonoid cephalopod Alsatites
Fossil of the Ordovician-Modern sea star trace fossil ichnogenus Asteriacites
Fossilized skull and partial neck of the Middle Triassic plesiosaur relative Augustasaurus
Restoration of the Middle Triassic plesiosaur relative Augustasaurus
Fossilized skeleton of the Early Cretaceous-Oligocene turtle Adocus beatus
Map of fossil trackways including (green) those of the Early Jurassic dinosaur footprint ichnogenus Anomoepus
Fossilized skeleton of the gar Atractosteus
Fossils of the gar Atractosteus
Fossil of the Early Devonian-Permian eurypterid ("sea scorpion") Adelophthalmus
Fossils of the Early Devonian-Permian eurypterid ("sea scorpion") Adelophthalmus
Restoration of the Permian synapsid (mammal precursor) Aerosaurus
Illustration of a fossilized skull of the Permian synapsid (mammal precursor) Aerosaurus
Life restoration of the Carboniferous amphibian Anconastes
Diagram illustrating the sizes of three specimens of the Late Cretaceous long-necked dinosaur Alamosaurus, with an anachronistic human to scale
Fossilized skull of the Late Triassic phytosaur Angistorhinus
A living Accipiter hawk
Fossilized scutes of the Paleocene Alligator relative Akanthosuchus
Restoration of the Paleocene mesonychid mammal Ankalagon saurognathus (top)
Restoration of the Paleocene mesonychid mammal Ankalagon saurognathus (top)
A living Aythya duck
Fossilized teeth (W) of the Cambrian–Early Ordovician conodont Acanthodus
Fossilized teeth of the Cambrian–Early Ordovician conodont Acanthodus
Illustration of fossils of the Cambrian trilobite Acidiscus
Illustration of fossils of the Cambrian trilobite Acimetopus
Fossil of the Silurian-Early Devonian eurypterid ("sea scorpion") Acutiramus
Life restoration of the Silurian-Early Devonian eurypterid ("sea scorpion") Acutiramus
Illustration of fossils of the Cambrian trilobite Analox
Fossil of the Early-Middle Ordovician trilobite Asaphus
Restoration of the Middle Devonian arachnid Attercopus
A living Acanthocybium solandri, or wahoo
A living Actinocyclus sea slug
A living Alca, or razorbill
A living Alopias superciliosus, or bigeye thresher
A living Aluterus filefish
Illustration of a living Ammodytes
A living Anisotremus grunt
A living Apalone softshell turtle
Shells of Arcinella jewel box clams
A living Ardea cinerea, or grey heron
Reconstructed skeleton of the Late Triassic Aetosaurus. Othniel Charles Marsh (1895).
Restorative model of the Late Cretaceous marsupial relative Alphadon
Restoration of the Late Cretaceous oviraptorosaur Anzu
Fossilized skeleton of the Late Cretaceous sea turtle Archelon
Restoration of the Permian amphibian Acheloma
Fossilized skeleton of the Permian amphibian Acheloma
Illustration of a reconstructed skull and restoration of the head of the Permian primitive reptile Acleistorhinus
Illustration of a fossilized skull in multiple views of the Permian primitive reptile Acleistorhinus
Shell of an Acamptogenotia sea snail
Shell of an Acmaea sea snail
Foliage and flowers of a living Actinidia
Restoration of the Oligocene baleen whale Aetiocetus
Restoration with insets detailing the anatomy of the Oligocene alder tree Alnus heterodonta
Leaf and other anatomical components of a living Anamirta vine
Restoration of the Late Devonian-Carboniferous tree Archaeopteris macilenta with insets detailing its anatomy
Fossil of the Cambrian trilobite Asaphiscus
Restorative portrait of the Permian synapsid (mammal precursor) Apsisaurus
Life restoration of the Permian reptile Araeoscelis
Restoration of the Permian reptile Araeoscelis. Samuel Wendell Williston (1914).
Restoration of the Permian amphibian Archeria
Life restoration of the Permian amphibian Archeria
Fossilized shell of the Early-Late Cretaceous ammonoid cephalopod Acanthoceras
Fossilized shell of the Late Cretaceous ammonoid cephalopod Acompsoceras
Restoration of the Late Triassic synapsid (mammal precursor) Adelobasileus
Restoration of the Late Cretaceous horned dinosaur Agujaceratops
Shells in differing orientations of Akera sea hares
Shell of an Ancilla sea snail
Reconstruction of a fossilized skull of the Late Cretaceous duck-billed dinosaur Angulomastacator
Fossilized shell of the Late Jurassic-Early Cretaceous ammonoid cephalopod Aspidoceras
Life restoration of the Early Cretaceous long-necked dinosaur Astrodon
Fossilized skeleton of the Oligocene Alligator prenasalis
Shell of an Ancilla olive sea snail
A living Aegolius funereus, or boreal owl
A living Acris crepitans, or northern cricket frog
Fossilized skeleton of the Eocene pig-nosed turtle Allaeochelys
Fossilized forelimbs of the Miocene Alligator olseni, or Olsen’s Alligator
Life resoration of the Miocene-Pleistocene elephant relative Anancus
Fossilized partial mandible of the Eocene-Oligocene bear dog Angelarctocyon
Modern fruit, whole and in cross-section of an Annona tree
Fossil of the Cambrian velvet worm relative Aysheaia
Fossilized skeleton of the Cretaceous armored dinosaur Animantarx
Illustration of fossilized teeth from the Late Cretaceous tyrannosaur Aublysodon
Fossilized shell of the Eocene-Oligocene turtle Anosteira
Flowers and foliage of a living Acacia
A living Accipiter gentilis, or northern goshawk
Fossilized needles of an Amentotaxus, or catkin-yew
A living Anobium beetle
Fruit and foliage of a living Artocarpus, the genus including bread and jackfruit
A living Aythya collaris, or ring-necked duck
A living Antigone canadensis (formerly Antigone canadensis), or sandhill crane
A living Agkistrodon contortrix, or copperhead
A living Ambystoma jeffersonianum, or Jefferson salamander
Restoration of the Cambrian arthropod Aglaspis
Illustration of a living Agathidium round fungus beetle
Fossil of the Triassic-Jurassic crustacean Antrimpos
Foliage and cones of a living Araucaria tree
Fossilized cone of the Triassic-modern tree Araucaria
Shell of a living Anguispira alternata land snail, or flamed tigersnail
A living Anoxypristis cuspidata, or knifetooth sawfish
Living Amphibalanus improvisus, or bay barnacles encrusting a bivalve shell
Shell of a modern Astarte bivalve
Divider
  • Fossilized shell of the Silurian-Early Triassic mollusc Bellerophon
  • Life restorationg of the Carboniferous amphibian Brachydectes
  • Reconstructed skull of Brachydectes in multiple views; complete skull viewed from right side (top), cranium viewed from above (middle), and cranium viewed from below (bottom)
  • Restoration of the Carboniferous amphibian Brachydectes
  • Restoration of the Permian amphibian Broiliellus
  • Restoration of the Late Jurassic sauropod dinosaur Barosaurus rearing to defend itself against a pair of the theropod Allosaurus
  • Restoration of the Late Cretaceous plesiosaur Brachauchenius hunting a hesperornithiform bird
  • Diagram illustrating the Late Jurassic sauropod dinosaur Brachiosaurus with an anachronistic human to scale
  • Restoration of a herd of the Late Jurassic sauropod dinosaur Brontosaurus
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Baculites
  • Restoration of the Late Cretaceous bony fish Bananogmius
  • Fossilized guard of the Late Cretaceous belemnoid cephalopod Belemnitella
  • Fossilized skeleton of the Late Cretaceous bony fish Belonostomus
  • Segment of a fossilized shell of the Late Cretaceous ammonoid cephalopod Baculites
  • Segment of a fossilized shell of the Late Cretaceous ammonoid cephalopod Baculites showing sutures and remnant aragonite
  • Segment of a fossilized shell of the Late Cretaceous ammonoid cephalopod Baculites. The original aragonite of the outer shell and inner chamber walls has dissolved away, leaving this articulated internal mold.
  • A living Betula, or birch tree
  • Mummified specimen found in Alaska of the Pleistocene-Holocene Bison priscus, or steppe bison. This specimen, known as "Blue Babe" after the blue ox of Paul Bunyan folklore, derives its unusual coloration from a chemical reaction between the phosphorus in its skin and iron in the surrounding soil to produce a coating of vivianite.
  • Fossilized skeleton of the Pleistocene-Holocene bovid Bootherium bombifrons, or Harlan's musk ox.
  • Fossil of the Eocene crab Branchioplax
  • Shell of a Bursa corrugata frog shell sea snail
  • Fossil slab and counterslab of the bony fish Boreosomus
Fossil of the Silurian trilobite Balizoma
Fossil of the sauropod dinosaur footprint ichnogenus Brontopodus
Restoration of the Eocene whale Basilosaurus
Fossil of the Cambrian trilobite Bristolia
Mold fossil of a head of the Cambrian trilobite Bristolia
Restoration of the Early Ordovician-Silurian trilobite Bumastus
Segment of the fossilized shell of the Late Cretaceous ammonoid cephalopod Baculites
Shell of a Barbatia, or bearded ark clam
Fossilized skeleton of the Cretaceous turtle Basilemys
Fossilized shell of the Late Cretaceous ammonoid cephalopod Bostrychoceras
Shell of a Bulimulus land snail
A living Bullina bubble sea snail
A living Balaenoptera physalus, or fin whale
Fossilized skeleton of the Pliocene whale Balaenula
Living Balanophyllia elegans stony coral
Fossilized skull of the Miocene-Pliocene false saber-toothed cat Barbourofelis
A living Bassariscus astutus (left), or ringtail
A living Beringraja binoculata, or big skate

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Fossilized skeleton of the eocene-?Miocene boa snake Boavus
Restoration of the Miocene grenadier fish Bolbocara (bottom)
Illustration of a living Borophryne apogon, or netdevil
Restorative portrait of the Miocene oreodont mammal Brachycrus
A living Brachyramphus murrelet
A living Branta bernicla, or black brant
A living Bubo virginianus, or great horned owl
A living Bucephala albeola, or bufflehead
Shells in multiple views of Bulla gouldiana, or the California bubble sea snail
A living Buteo jamaicensis, or red-tailed hawk
A living Buteo swainsoni, or Swainson's hawk.
Fossilized skeleton of the Paleocene-Eocene pantodont mammal Barylambda
Life restoration of the Paleocene-Eocene pantodont mammal Barylambda
Restoration of the Eocene uintathere mammal Bathyopsis being hunted by mesonychids
Fossilized cranium of the Eocene uintathere mammal Bathyopsis
Fossilized skeleton of the Late Cretaceous-Eocene crocodilian Borealosuchus
Skeletal reconstruction of the Eocene-Oligocene bear-dog Brachyrhynchocyon
A living Bruchus leaf beetle
A living Buteo hawk
Restoration of the Late Cretaceous bony fish Bonnerichthys with an anachronistic scuba diver to scale
A living Bairdiella chrysoura, or American silver perch
Illustration of a living Balaenoptera acutorostrata, or common minke whale
Living Balanus trigonus barnacles
A living Balistes triggerfish
Shells of Batillaria mudcreeper snails
Berries of a living Lindera melissifolia (formerly Benzoin melissifolium), also known as pondberry or southern spicebush
Shell in side view (top) and bottom view of Biomphalaria havanensis, or the ghost rams-horn
Fossilized skeleton of the Pleistocene Bison latifrons, also known as the giant bison or long-horned bison
A living Blarina carolinensis, or southern short-tailed shrew
A living Blarina brevicauda, or northern short-tailed shrew
Restoration of the Miocene musk deer Blastomeryx. Robert Bruce Horsfall (1913).
A living Boa constrictor
Underside of a fossilized cranium of the Eocene anthracothere mammal Bothriodon
Shell of a Brachycythara sea snail
Living male (left) and female (right) Anaxyrus quercicus, or oak toads
A living Anaxyrus fowleri (formerly Bufo fowleri), or Fowler's toad
A living Bulimulus land snail
Shell of a Bursa rugosa frog shell sea snail
Shell in multiple views of a Busycon contrarium whelk
Shell in multiple views of a Busycon carica, or knobbed whelk
Shell in multiple views of a Sinistrofulgur perversum
A living Buteo lineatus, or red-shouldered hawk
A living Buteo platypterus, or broad-winged hawk
A living Butorides virescens, or green heron
Diagram illustrating the Eocene whale Basilosaurus with an anachronistic human to scale
A living Bison bison
Fossilized skull of the Miocene-Pliocene bone-crushing dog Borophagus
Fossil of the Early Ordovician-Silurian trilobite Bumastus
Illustration of a fossil of the Early Ordovician-Silurian trilobite Bumastus
Reconstruction (left) of a fossil (right) of the Ordovician sea urchin Bothriocidaris. The short spines which were attached to the tubercles are not drawn.
Restoration of the Carboniferous Chimaera relative Belantsea
Living Botryococcus green algae
Illustration of a living Belone needlefish
Shell in multiple views of a Bittium cerith sea snail
Illustration of a living Bregmaceros, or codlet
Shell of a Bullia nassa mud sea snail
Preserved specimen of Buccinum undatum, or the common whelk sea snail
Portrait of a living Balaenoptera baleen whale
A living Brevoortia tyrannus, or Atlantic menhaden
Illustration of a living Batrachoides toadfish
Diagram of the known fossil material of the Late Cretaceous dromaeosaurid ("raptor") Bambiraptor
Restoration of the Late Cretaceous horned dinosaur Brachyceratops
Restoration of the Late Cretaceous Alligator relative Brachychampsa
Fossilized natural mummy of the Late Cretaceous duck-billed dinosaur Brachylophosaurus
Shoot and flowers of a modern Berberis, or barberry
Illustration of a fossil of the Cambrian trilobite Bathynotus
Restoration of the Cambrian trilobite Biceratops
Fossilized skeleton of the Triassic bony fish Birgeria
Fossils and restoration of the Triassic bony fish Birgeria
Life restoration of the Triassic bony fish Birgeria
Amber-entombed specimen of the Early-Late Cretaceous ant Baikuris
A living Brachaelurus, or blind shark
Amber-entombed specimen of the Late Cretaceous ant Brownimecia
Restoration of the Late Cretaceous tyrannosaur Bistahieversor
Illustration of fossils of the Cambrian trilobite Bathydiscus
Fossil of the Middle Devonian trilobite Bellacartwrightia
Illustration of fossils of the Cambrian trilobite Bolboparia
Fossil of the Ordovician echinoderm Bolboporites
Fossilized heads of the Silurian eurypterid ("sea scorpion") Buffalopterus
Living Busycotypus whelk sea snails
A living Balearica, or crowned crane
Restoration of the Pliocene toothed whale Bohaskaia
Shell of a Boonea seminuda sea snail
Flower of a living Brasenia
A living Brotula cusk eel
Amber-entombed specimen of the Early-Late Cretaceous ant Baikuris
Fossilized skeleton of the Late Cretaceous crocodilian Borealosuchus
Illustration of a fossilized skull of the Permian primitive reptile Bolosaurus
Illustration and interpretive diagram of a fossilized skull of the Permian primitive reptile Bolosaurus
Illustration in multiple views of a fossilized partial mandible of the Permian primitive reptile Bolosaurus
Fossilized skeleton of the Late Jurassic long-necked dinosaur Brontosaurus
Shell of a Bathybembix sea snail
A living Botaurus lentiginosus, or American bittern
Fossilized bony armor of the Late Devonian placoderm fish Bothriolepis
Restoration of the Late Devonian placoderm fish Bothriolepis
Shell in multiple views of a Bostrycapulus aculeatus
Illustration of a living Bythaelurus catshark
Fossilized skeleton of the Eocene crocodilian Boverisuchus
Illustration of a shell of a Bulimulus dealbatus land snail
Life restoration of the Early Cretaceous crocodilian relative Bernissartia
Fossils of the Middle Jurassic-Cretaceous sea star Betelgeusia
Fossilized skull of the Late Triassic phytosaur Brachysuchus
Restoration of the Late Cretaceous horned dinosaur Bravoceratops
Life restoration of the mysterious Cambrian animal Branchiocaris
Restorative model of the Eocene shrew-like mammal Batodonoides
Flowers of a living Bauhinia tree
Fruit and foliage of a living Beilschmiedia
Fossilized skeleton of the Miocene-modern bird of prey Buteogallus
Restorative portrait of the Permian synapsid (mammal prescursor) Burnetia
Fossilized vertebrae of the Pliocene baleen whale Balaenotus
Fossilized skeleton of the Eocene conger eel Bolcyrus
Divider
Restoration of the Pliocene-Holocene camel Camelops
  • Fossilized skeleton of the Pleistocene dwarf pronghorn Capromeryx
  • Fossilized skeleton of the Miocene pronghorn-relative Cosoryx
  • Fossilized stems from the Carboniferous-Permian horsetail relative Calamites
A fossilized rhizoid of the Carboniferous-Permian horsetail relative Calamites
  • A polished round of the permineralised Late Devonian-Carboniferous wood Callixylon
  • Fossilized shell of the Middle Ordovician-Silurian nautiloid cephalopod Cameroceras
  • Restoration of the Middle Ordovician-Silurian nautiloid cephalopod Cameroceras feeding on a Aphetoceras, while a quartet of Cyclostomiceras swim by
  • Fossil of the Ordovician-Silurian tabulate coral Catenipora
  • Fossil of the Middle-Late Ordovician trilobite Ceraurus
  • Fossil of the Late Ordovician trilobite Chasmops
  • Illustration of a fossil of the Cambrian-modern burrow ichnogenus Chondrites
  • Fossil of the Cambrian-modern burrow ichnogenus Chondrites
  • Fossil of the Carboniferous tabulate coral Cladochonus
  • Restoration of the Late Devonian shark Cladoselache
  • Assemblage of fossils of the Cambrian graptolite Climacograptus
  • Restoration of the Carboniferous tetrapodomorph Colosteus
  • Fossilized shell of the Late Devonian-Permian brachiopod Composita
  • Fossilized foliage of the Carboniferous-Permian conifer relative Cordaites
  • Fossil of the Middle Ordovician-Carboniferous horn coral Cornulites
  • Fossil of the Carboniferous shark Ctenacanthus
  • Fossilized foliage from the Carboniferous seed fern Cyclopteris
  • Fossilized shells of the Middle-Late Devonian brachiopod Cyrtospirifer
  • Assemblage of fossilized shells of the Ordovician brachiopod Cincinnetina
  • Fossil found in Ohio of the Late Devonian shark Cladoselache
  • Fossil of the Ordovician bryozoan Constellaria
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Calycoceras
  • Life restoration of a herd of the Late Jurassic sauropod dinosaur Camarasaurus
  • Life restoration of the Late Jurassic ornithopod dinosaur Camptosaurus
  • A living Carcharias sand tiger shark
  • Life restoration of the Late Triassic-Eocene lungfish Ceratodus
  • Restoration of the Late Jurassic ceratosaur Ceratosaurus
  • Restoration of the Late Cretaceous-Eocene choristoderan reptile Champsosaurus
  • Restoration of the Late Triassic coelacanth fish Chinlea
  • Fossilized skeleton of the Late Cretaceous bony fish Cimolichthys
  • Life restoration of the face of the Late Cretaceous multituberculate mammal Cimolomys
  • Restoration of the Late Cretaceous mosasaurid Clidastes
  • Diagram illustrating the known fossil material of the Late Jurassic theropod dinosaur Coelurus
  • Restoration of the Late Cretaceous shark Cretoxyrhina, or the Ginsu shark
  • Fossilized shell of the Middle Jurassic ammonoid cephalopod Cadoceras
  • Fossilized shell of the Early Jurassic-Early Cretaceous ammonoid cephalopod Calliphylloceras
  • Fossilized shell of the Early Jurassic-Early Cretaceous ammonoid cephalopod Calliphylloceras
  • Restoration of the Late Triassic-Middle Jurassic nautiloid cephalopod Cenoceras
  • Fossilized shell of the Middle Triassic ammonoid cephalopod Ceratites
  • Fossilized foliage of the Permian-Late Cretaceous fern Cladophlebis
  • Fossilized shell of the Early Cretaceous ammonoid cephalopod Cleoniceras
  • Fossils of the Devonian-Permian horn coral Caninia
  • Restoration of the Silurian-Early Devonian primitive land plant Cooksonia
  • Restoration of the Late Triassic theropod dinosaur Camposaurus
  • Fossilized shell of the Cretaceous marine bivalve Caprina
  • Restoration of the Late Triassic theropod dinosaur Chindesaurus
  • Restorative model of the hypothetical trackmaker of the Late Triassic ichnogenus Chirotherium with real fossil footprints in the background
  • Life restoration of Coelophysis kayentakatae
  • Fossilized shell of the Late Cretaceous ammonoid Collignoniceras
  • Extremely hypothetical Restoration of the mysterious Late Triassic reptile Crosbysaurus
  • Skeletons look identical
    Modern mounted skeleton of Canis lupus, the grey wolf, to scale with a fossilized skeleton of the Pleistocene wolf Canis dirus, or dire wolf
  • Fossilized cranium of the Pliocene-Pleistocene hyena Chasmaporthetes
  • Life restoration of the Pliocene-Holocene elephant relative Cuvieronius
Fossilized elements of the Carboniferous conodont Cavusgnathus
A living Cliona sponge
Illustration in multiple views of a fossilized skull of the Pleistocene Canis armbrusteri, or Armbruster's wolf
Illustration of a fossilized cranium of the Pleistocene Canis armbrusteri, or Armbruster's wolf
Fossil of the Devonian-Triassic arthropod trackway ichnogenus Cruziana
Fossil of the Devonian-Triassic arthropod trackway ichnogenus Cruziana
Fossilized shell of the Permian ammonoid cephalopod Cyclolobus
Restoration of the Late Triassic ichthyosaur Californosaurus
Diagram depicting the Late Triassic ichthyosaur Californosaurus with an anachronistic human to scale.
Fossilized shell of the Late Cretaceous ammonoid cephalopod Calycoceras
A living Cerithidea horn sea snail
Two views of a fossilized shell of a Cerithium cerith sea snail
50 second video of snails (most likely Natica chemnitzi and Cerithium muscarum) feeding on the sea floor in the Gulf of California, Puerto Peñasco, Mexico
Fossilized shell of the Early Cretaceous ammonoid cephalopod Crioceratites
Fossilized shell of the Early Cretaceous ammonoid cephalopod Crioceratites
Fossilized shell of the Early Cretaceous ammonoid cephalopod Crioceratites
Fossilized shell of the Late Jurassic-Oligocene nautiloid cephalopod Cymatoceras
Fossilized partial skeleton of the Middle-Late Triassic ichthyosaur Cymbospondylus
Restoration of the Middle-Late Triassic ichthyosaur Cymbospondylus
Diagram illustrating the Middle-Late Triassic ichthyosaur Cymbospondylus with an anachronistic human to scale.
A living Calidris alba, or sanderling
Shell of a Californiconus californicus, or California cone sea snail
A living Calliostoma annulatum, or purple-ring top sea snail
A modern Calliostoma tricolor, or three-coloured top shell sea snail
Illustration of a living Calosoma, or caterpillar hunters
Flowers of a Calyptranthes, or lidflower
A Camponotus festinatus carpenter ant
A living Canis latrans, or coyote
A living Carcharodon carcharias, or great white shark
A living Carya, or hickory tree
A living Cathartes aura, or turkey vulture
Flowers of living Ceanothus, or California lilac
Foliage and fruit of a living Celtis, or hackberry
A living Cepphus columba, or pigeon guillemot
A living Cercocarpus, or mountain mahogany
A living Cetorhinus, or basking shark
Restoration of the Miocene-Pliocene whale Cetotherium
Illustration of a living Chaenophryne dreamer
Close-up portrait of a Chauliodus, or viperfish
Flock of living Anser caerulescens (formerly Chen caerulescens), or snow goose
Restoration of the Pleistocene-Holocene Chendytes, or Law's diving-goose
A living Chlamys hastata, or spear scallop
Shell of Chlamys swifti, or Swift's scallop
Three living Chlorostoma sea snails
A living Chrysocyon brachyurus, or maned wolf
A living Cinnamomum, or cinnamon tree
A living Citharichthys stigmaeus, or speckled sanddab
Shells in multiple orientations of Clathrodrillia sea snails
A living Cnemidophorus, or whip-tail lizard
A living Colaptes, or flicker
Shell in two views of a Conasprelloides cone sea snail
Shell of a Conus regularis, or regular cone sea snail
Shell in two views of a Conus scalaris, or ladder cone sea snail
A living Copris scarab
A living Coragyps atratus, or American black vulture
Shell of a Crassispira sea snail
Fruit of four difference species of Crataegus, or hawthorn tree
Living Crepidula adunca, or hooked slipper sea snails
Shell in multiple views of a Crepidula onyx, or onyx slipper sea snail
A living Crotalus viridis, or prairie rattlesnake
Branch and fruit of a Cryptocarya
A living Cryptotermes, or drywood termite
A living Culicoides biting midge
Branch with fruit of a Cupania
A living Cupressus, or cypress tree
A living Cyanocitta stelleri, or Steller's jay
Illustration of a living Cyclothone bristlemouth
A living Cygnus columbianus, or tundra swan
Underside of a fossilized cranium of the Oligocene-Miocene bone-crushing dog Cynarctoides
Fossilized cranium of the Miocene bear-dog Cynelos
Fossilized mandible of the Miocene bear-dog Cynelos
Illustration of a living Cyrtonyx quail
Restoration of the Permian synapsid (mammal precursor) Cutleria
Flower of a living Caesalpinia
A living Calcarius lapponicus, or Lapland longspur
A living Calcarius ornatus, or chestnut-collared longspur
A living larva of a Caliroa sawfly
Illustration of a living Callomyia flat-footed fly
A living Camponotus, or carpenter ant
A living Carabus ground beetle
A living Cardiophorus click beetle
A living member of the vine genus Cardiospermum
A living Haemorhous cassinii (formerly Carpodacus cassinii), or Cassin's finch
Foliage and fruit of a living Celastrus, or staff vine
A living Ceratina, or small carpenter bees
Restoration of the Paleocene-Eocene crocodilian Ceratosuchus
Flowers of a living Cercis or redbud tree
A living Chalybion, or blue mud dauber
A stand of living Chamaedorea palms
A living Cheilosia hoverfly
A living Chilocorus ladybug
A living Chironomus midge
A living Chondestes grammacus, or lark sparrow
A living Chrysogaster hoverfly
Fossilized tooth of the Late Cretaceous-Paleocene multituberculate mammal Cimexomys
A living Cleonus weevil
A living Clubiona, or leafcurling sac spider
A living Coccinella ladybug
A living Colaptes auratus, or northern flicker
A living member of Colubrina
Illustration of a living Coniatus weevil
A living Conotrachelus weevil
A living Corizus scentless plant bug
A living Cryptocheilus spider wasp
A living Cryptophagus silken fungus beetle
A living Cryptorhynchus weevil
A living Culex mosquito
A living Curculio, or acorn weevil
A living Cylindrotoma crane fly
A living Cynomys, or prairie dog
Fossil of the Early-Middle Ordovician trilobite Colpocoryphe
Fossilized tooth of the Miocene-Pliocene shark Cosmopolitodus hastalis, or broad-toothed mako
Fossilized shells of the Miocene-Pleistocene scallop Chesapecten
A living Crocodylus
A living Calidris canutus, or red knot
A living Calidris pusilla, or semipalmated sandpiper
Shell of a Calliostoma euglyptum, or sculptured top shell
Shell of a Calliostoma jujubinum
Shell of a Calliostoma roseolum
Illustration in multiple views of the shell of a Calliostoma tampaense
Illustration in multiple views of the shell of a Calliostoma yucatecanum
Fossilized skeleton of the Pliocene-Holocene camel Camelops
Restoration of the Pliocene-Holocene camel Camelops
Shell in multiple views of a Cancellaria reticulata, or common nutmeg
Illustration in multiple views of the shell of a Cancilla mitre shell sea snail
A living Cardinalis cardinalis, or northern cardinal
A living Caretta caretta, or loggerhead sea turtle
Living Carex, or true sedge
A living Carphophis amoenus, or worm snake
Shell of a Carychium land snail
A living Ardea alba, or great egret
Shell in multiple views of a Cassis madagascariensis, or queen helmet sea snail
A living Castor canadensis, or North American beaver
A living Centropomus, or snook
Living Cerastoderma cockles
Shells of Cerithideopsis pliculosa, or the plicate horn shell sea snail
Shell of a Cerithium muscarum cerith sea snail
A living Ceryle rudis, or pied kingfisher
A living Chaetopleura apiculata chiton
A living Chamelea venus clam
A living Chelonia mydas, or green sea turtle
Shells of the Pliocene scallop Chesapecten jeffersonius
Shell in multiple views of a Chicoreus brevifrons, or West Indian murex
Shell of a Chicoreus florifer, or flowery lace murex
A living Chilomycterus, or burrfish
Exteriors (above) and interiors of shells of Chione cancellata venus clams
Shells in differing orientations of Chrysallida pyram sea snails
Fossilized skeleton of the Pliocene-Pleistocene Ciconia maltha, also known as the asphalt stork or La Brea stork
A living Circus cyaneus, or hen harrier
Fossilized Cladocora stony coral
A living Clangula hyemalis, or long-tailed duck
Shell of a Clavatula sea snail
A living Aspidoscelis sexlineata (formerly Cnemidophorus sexlineatus), or six-lined racerunner
A living Coccyzus americanus, or yellow-billed cuckoo
Living Colpophyllia natans, or boulder brain coral
Shell in multiple views of Columbella mercatoria dove sea snails
Fossil of the Miocene-Pleistocene barnacle Concavus
Illustration of a living Conepatus leuconotus, or American hog-nosed skunk
Shell in multiple views of a Conus anabathrum cone sea snail
Shell in multiple views of a Conus daucus cone sea snail
Shell in multiple views of a Conasprella delessertii (formerly Conus delessertii), or Sozon's cone sea snail
Shell in multiple views of a Conasprella jaspidea (formerly Conus jaspideus), or jasper cone sea snail
Shell in multiple views of a Conus patricius, or patrician cone sea snail
Shell in multiple views of a Conus sennottorum, or Sennett's cone sea snail
Shell in multiple views of a Conus spurius, or alphabet cone sea snail
Shell of a Coralliophila murex sea snail
A living Corvus ossifragus, or fish crow
A living Coturnicops noveboracensis, or yellow rail
Shell of a Crepidula maculosa slipper sea snail
Shell of a Crepidula plana eastern white slippersnail
A living Crotalus adamanteus, or eastern diamondback rattlesnake
Shell in multiple views of a Crucibulum spinosum, or spiny cup-and-saucer snail
Shell in multiple views of a Crucibulum striatum, or striate cup-and-saucer sea snail
A living Cryptotis parva, or North American least shrew
A living Cyanocitta cristata, or blue jay
A living Cygnus buccinator, or trumpeter swan
Shell of a Cymatosyrinx sea snail
Living Cymodocea sea grass
A modern Cynoscion drum
A living Cyphoma gibbosum, or flamingo tongue snail
Shell in multiple views of a Cypraecassis helmet sea snail
Shell in multiple views of a Cyrtopleura costata, or angel wing clam
Fossilized fronds of the Carboniferous seed fern Callipteridium
Fossil of the Silurian trilobite Calymene celebra
A living Chiloscyllium longtail carpet shark
A living Chiton
A living Carcharhinus obscurus, or dusky shark
A living Carcharias taurus, or sand tiger shark
A living Carcharodon shark
A living Chelydra serpentina, or common snapping turtle
Electron micrograph of a Coccolithus alga
Foliage of a living Canarium tree
Shell in multiple views of a Conus ebraeus, or black-and-white cone sea snails
A living Conus geographus, or the geography cone sea snail
Fossil of the Jurassic-Cretaceous cycad relative Cycadeoidea
Fossilized fruit of a Craigia plant
Fossils in enrolled posture of the Silurian trilobite Calymene niagarensis
Fossil of the Silurian eurypterid ("sea scorpion") Carcinosoma
Restoration of the Carboniferous Chimaera relative Caseodus
Chancelloria
Restoration (foreground) of the Permian-Jurassic lobe-finned fish Coelacanthus
Fossilized skeleton of the Permian-Jurassic lobe-finned fish Coelacanthus
Fossilized skeleton of the Carboniferous-Permian reptile relative Cricotus
Illustration of a fossilized skull and ventral scutes of the Carboniferous-Permian reptile relative Cricotus. Edward Drinker Cope (1884).
Fossilized stem segments of the Silurian crinoid ("sea lily") Crotalocrinites
Fossilized calyx and partial stem of the Silurian-Permian crinoid ("sea lily") Cyathocrinites
Restoration of the Pleistocene Cervalces scotti, or stag-moose
Life restoration of the Miocene-Pleistocene horned gopher Ceratogaulus. Robert Bruce Horsfall (1913).
Fossilized skull of the Miocene pronghorn Cosoryx
A living Cynomys ludovicianus, or black-tailed prairie dog
Restoration of a dead Late Cretaceous duck-billed dinosaur, Claosaurus, floating in the Western Interior Sea of Kansas, while a Cretoxyrhina and two Squalicorax prepare to scavenge it
Fossilized calyx of the Carboniferous crinoid ("sea lily") Cydrocrinus
A living Centropristis, or sea bass
A living Citharichthys large-tooth flounder
A living Conger
Electron micrograph of the shell of a Cyclammina foraminiferan
Fossilized vertebrae in multiple views of the Cretaceous plesiosaur Cimoliasaurus
Illustration of a fossilized tibia of the Late Cretaceous theropod dinosaur Coelosaurus antiquus
A living Callinectes sapidus, or Chesapeake blue crab
A living Calonectris shearwater
A living Cancer irroratus, or Atlantic rock crab
A living Myodes gapperi, or southern red-backed vole
Shell in multiple views of a Crepidula fornicata, or common slipper shell sea snail
Shells in differing orientations of Colus whelk sea snails
Illustration of a living Cymindis ground beetle
Living Chelonibia acorn barnacles
Fossilized skeleton of the Carboniferous coelacanth Caridosuctor
Life restoration of the Late Cretaceous horned dinosaur Centrosaurus
Restoration of the Late Cretaceous horned dinosaur Cerasinops
Restoration of the Late Cretaceous horned dinosaur Chasmosaurus
Fossilized hand and foot bones of the Late Cretaceous oviraptorosaur Chirostenotes
Fossilized skeleton of the Late Cretaceous duck-billed dinosaur Corythosaurus
Flowers and foliage of living Canavalia, or jack-beans
Life restoration of the Paleocene primate relative Carpolestes
Fossilized skeleton of the Eocene turtle Chisternon
Flower of a living Clematis
Illustration of fossilized vertebrae of the Late Cretaceous-Eocene snake Coniophis. Othniel Charles Marsh (1892).
A living Cornus, or dogwood
Fossilized leaf from a Credneria tree
A living Culiseta mosquito
Living Cedrela trees
Flowers of a living Cladrastis, or yellowwood
A taxidermied Conuropsis carolinensis, or Carolina parakeet
Fossil of the Cambrian arthropod Canadaspis
Restoration of the Cambrian arthropod Canadaspis (left)
Fossil of the Triassic bony fish Colobodus
Fossilized skeleton of the Triassic bony fish Colobodus
Fossilized shell of the Early Jurassic ammonoid cephalopod Coroniceras
Fossilized carapace of the Paleocene-Miocene crab Calappilia
Shell of a Cardites marine bivalve
Restoration of the Carboniferous-Permian amphibian Chenoprosopus
Fossilized skull in multiple views of the Carboniferous-Permian amphibian Chenoprosopus
Fossilized skeleton of the Middle Triassic-Paleocene bony fish Coelodus
Restoration of the Late Triassic-Early Jurassic theropod dinosaur Coelophysis with an anachronistic human to scale
Fossilized skeleton of the Late Triassic-Early Jurassic theropod dinosaur Coelophysis
A living Chaetodipus pocket mouse
A living Cophosaurus texanus, or greater earless lizard
Illustration of a fossil and restoration of the Early Ordovician nautiloid cephalopod Cassinoceras
Fossils (1 and 2) of the Silurian eurypterid ("sea scorpion") Clarkeipterus
Fossils (1-8) of the Silurian eurypterid ("sea scorpion") Clarkeipterus
A living Craniella sponge
Fossils and restoration of the Silurian eurypterid ("sea scorpion") Ctenopterus
Fossils (1-7) of the Silurian eurypterid ("sea scorpion") Ctenopterus
A living Calidris melanotos, or pectoral sandpiper
A living Calonectris borealis, or Cory's shearwater
A living Carcharhinus falciformis, or silky shark
Illustration of a living Centropristis striata, or black sea bass
Illustration of a living Ceratoscopelus lanternfish
A living Cerorhinca monocerata, or rhinoceros auklet
A living Chilomycterus schoepfi, or striped burrfish
Living Ciconia storks
Living Clathrus stinkhorn fungi
A Coelopleurus sea urchin
A living Conger oceanicus, or American conger
A living Coscinodiscus diatom
Shell of a Cotonopsis lafresnayi, or well-ribbed dove sea snail
Shells of Cumingia marine clams
Illustration of a living Cynoscion nebulosus, or spotted seatrout
Known material diagram illustrating a reconstructed skull and body of the Late Triassic distant crocodilian relative Carnufex
Living Ceratophyllum, also known as coontails or hornworts
Trunk and foliage of a living Cercidiphyllum, or katsura tree
Fossilized skeleton of the Permian amphibian Cacops
Life restoration of the Permian amphibian Cacops
Fossilized skeletons of the Permian reptile Captorhinus
Restoration of the Permian reptile Captorhinus
Restoration of the Permian amphibian Cardiocephalus
Illustration of a fossilized cranium of the Permian primitive reptile Colobomycter
Fossilized skeleton of the Permian synapsid (mammal precursor) Cotylorhynchus
Restoration of the Permian synapsid (mammal precursor) Cotylorhynchus
Fossilized skeleton of the Permian synapsid (mammal precursor) Cotylorhynchus
Diagram illustrating the size of the Permian synapsid (mammal precursor) Cotylorhynchus, with an anachronistic human to scale
Fossilized skull of the Carboniferous-Permian reptile relative Cricotus
Fossil of the Carboniferous-Permian trilobit Cummingella
Foliage and cones of a living Calocedrus, or incense cedar
A living Choerodon wrasse
Shell of a Comitas sea snail
A taxidermied Cryptotis , or small-eared shrew
A living Crocuta crocuta, or spotted hyena
Restoration of the Cambrian echinoderm Camptostroma
A living Charina boa
Fossilized skeleton of the Permian-Early Cretaceous bony fish Caturus
Shells of Candona ostracods
A living Catagonus wagneri, or Chacoan peccary
Fruit and foliage of a living Cissus vine
Fruit and foliage of a living Combretum, or bushwillow
A living Corvus brachyrhynchos, or American crow
A living Crotalus atrox, or western diamondback rattlesnake
A living Crotaphytus collaris, or common collared lizard
Reconstruction of a fossilized skeleton of the Permian amphibian Cacops. Samuel Wendell Williston.
Fossilized skeleton of the Permian reptile Captorhinus
Fossilized skeleton of the Permian synapsid (mammal precursor) Casea
Diagram illustrating the Permian synapsid (mammal precursor) Casea with an anachronistic human to scale
Life restoration of the Permian synapsid (mammal precursor) Casea
Life restoration of the Permian synapsid (mammal precursor) Cotylorhynchus
Shell of a Cancellaria nutmeg sea snail
Restoration of the Late Cretaceous turtle Chupacabrachelys
Life restoration of the Late Cretaceous pterosaur Cimoliopterus (left) stealing fish from another pterosaur
Fossilized skulls of the Late Triassic–Early Jurassic tuatara relative Clevosaurus
Fossils of the Cretaceous sea urchin Conulus
Fossil of the Cambrian sponge Choia
Restoration of the Cambrian sponge Choia
A living Calamospiza melanocorys, or lark bunting
A living Caracara plancus, or southern crested caracara
A living Carduelis finch
Life restoration of the Paleocene primate relative Carpolestes simpsoni
A living Centrocercus urophasianus, or greater sage-grouse
A living Cercopis froghopper
A living Charadrius montanus, or mountain plover
A living Chordeiles minor, or common nighthawk
A living Coccothraustes vespertinus, or evening grosbeak
Fruit and foliage of a living Cocculus, or moonseed
Fossilized skull of the Eocene crocodilian "Crocodylus" affinis
Fossilized illium in multiple views of the Early Cretaceous Iguanodon relative Cedrorestes
Restoration of the Late Jurassic primmitive tyrannosaur Coelurus
Fossilized skull of the Eocene crocodilian Crocodylus acer
Shell and operculum of a living Campeloma freshwater snail
Fossilized skeleton of the Late Cretaceous-Eocene choristodere reptile Champsosaurus
Illustration in multiple views of a fossilized coracoid of the Late Cretaceous bird Cimolopteryx
Life restoration (figure 12) of the Early Triassic plesiosaur relative Corosaurus
Fossil of the Cambrian trilobite Conocoryphe
Restoration of the Carboniferous four-limbed animal precursor Crassigyrinus
Fossil of the Triassic crocodilian relative footprint ichnogenus Chirotherium
A living Charadrius vociferus, or killdeer
A living Chordeiles minor, or common nighthawk
A living Cistothorus stellaris, or sedge wren
Fossilized skeleton of the Eocene bony fish Cyclopoma
Fossilized tooth of the Carboniferous Chimaera relative Campodus
Restoration of the Carboniferous Chimaera relative Campodus
Restoration of the Early Devonian jawless fish Cephalaspis
Fossilized skeleton of the Early Devonian jawless fish Cephalaspis
Divider
  • Life restoration of the Oligocene-Miocene herbivorous marine mammal Desmostylus
  • Fossilized calyx of the Carboniferous crinoid ("sea lily") Decadocrinus
Life restoration of a swimming group of the Permian amphibian Diploceraspis
  • Cambrian graptolite Diplograptus
  • Restoration of the Silurian eurypterid ("sea scorpion") Dolichopterus
  • Mounted skull of the Late Devonian placoderm fish Dunkleosteus
  • Restoration of the Late Devonian placoderm fish Dunkleosteus
  • Restoration of several species of the Late Cretaceous ammonoid cephalopod Didymoceras
  • Diagram illustrating the Late Jurassic sauropod dinosaurs Diplodocus carnegii (green) and D. hallorum (orange) with an anachronistic human to scale.
  • Fossilized skull of the Late Jurassic-Early Cretaceous turtle Dorsetochelys
  • Fossilized head of the Late Ordovician-Middle Devonian trilobite Dalmanites
  • Fossil of the Late Ordovician-Middle Devonian trilobite Dalmanites
  • Fossil of the Middle Ordovician graptolite Didymograptus
  • Fossil of the Silurian-Jurassic alga Diplopora
  • Fossilized foliage from the Early-Late Devonian club moss relative Drepanophycus
  • Fossilized shell of the Early Jurassic ammonoid cephalopod Dactylioceras
  • Restoration of the Early Jurassic ammonoid cephalopod Dactylioceras
  • Fossilized shell of the Middle-Late Triassic marine bivalve Daonella
  • Fossilized shells of the Early Cretaceous ammonoid cephalopod Desmoceras
  • Fossilized shell of the Early-Late Cretaceous ammonoid cephalopod Douvilleiceras
  • Shell of a Dolicholatirus sea snail
  • Illustration of a fossilized skull from above (left) and below of the Cretaceous sea turtle Desmatochelys
  • Restoration of the Late Triassic aetosaur Desmatosuchus with an anachronistic human to scale
  • Restoration of the Early Jurassic theropod dinosaur Dilophosaurus resting
  • Restoration of the Late Triassic dinosaur relative Dromomeron
  • A living Desmodus, or vampire bat
  • Fossilized skeleton of the Oligocene-Miocene hornless rhinoceros Diceratherium.
Restoration of two species of the Silurian trilobite Deiphon
Fossil and mold of the Late Ordovician-Silurian trilobite Diacalymene
Fossil of the Cambrian trilobite Daguinaspis
Fossils of the Cambrian-modern arthropod trackway ichnogenus Diplichnites
Fossilized shell of a Discohelix sea snail
Life restoration of the Miocene bear-dog Daphoenodon
Fossilized skeleton of the Eocene-Miocene bear-dog Daphoenus
A school of living Decapterus, or mackerel scads
A living Dendragapus obscurus, or dusky grouse
A living Dendraster excentricus, or sea cake
A living Dendryphantes jumping spider
A living Dermochelys, or leatherback sea turtle
A living Deroceras land slug
Facial features of various Diomedea, or great albatross, species.
A living member of Diospyros, the tree genus including ebonies and persimmons
A living Dipodomys merriami, or Merriam's kangaroo rat
Illustration of a cluster of the Jurassic-modern brachiopod Discinisca
Shell of a Distorsio sea snail
Fossilized horns, jaws, and limb bones of the Miocene deer relative Dromomeryx
Fossilized jaws and teeth of the Eocene brontothere mammal Duchesneodus
Restoration of the Miocene-Pliocene manatee relative Dusisiren
A living Daphnia water flea
Restoration of the Eocene-Miocene bear dog Daphoenus
Living Dennstaedtia, or hayscented ferns
Preserved Dermatobia hominis, or human botfly specimen
A living Dermestes skin beetle
A living Diabrotica, or corn rootworm
Restoration of two of the Eocene even-toed ungulate Diacodexis being hunted by a primitive whale
Restoration of two of the Eocene even-toed ungulate Diacodexis
Illustration of a living Dicerca jewel beetle
A living Dicranomyia crane fly
A living Dicranota hairy-eyed cranefly
Fossilized skeleton of the Eocene-Miocene false saber-toothed cat Dinictis
Life restoration of the Eocene-Miocene false saber-toothed cat Dinictis. Robert Bruce Horsfall (1913).
Fossilized skeleton of the Miocene-Pliocene horse Dinohippus
A living Diploptera, or beetle cockroach
A living Dipodomys ordii, or Ord's kangaroo rat
Foliage and flowers of a living Dodonaea, or hop-bush
Preserved Dolichoderus ant
A living Doxocopa brush-footed butterfly
Restoration of the Late Cretaceous primitive tyrannosaur Dryptosaurus
Shell in multiple views of a Daedalochila uvulifera, or peninsula liptooth land snail
Fossilized cranium seen from above and below of the Pleistocene Dasypus bellus, or beautiful armadillo
Living Dendrogyra, or pillar coral
Shell of a Dermomurex elizabethae murex sea snail
Shell of a Dicathais white rock shell sea snail
Living Dichocoenia stokesi, or elliptical star coral
Shells of Diodora cayenensis, or Cayenne keyhole limpet
Living Diploria labyrinthiformis, or grooved brain coral
Shells of Donax variabilis, or coquina
A living Vanellus chilensis, or southern lapwing
Close-up portrait of a living Drymarchon corais, or indigo snake
A living Dryocopus woodpecker
Fossil of the Late Ordovician-Middle Devonian trilobite Dipleura
Restoration of the Late Cretaceous Alligator relative Deinosuchus
Fossilized mandible in multiple views of the Pleistocene Dasypus bellus, or beautiful armadillo
A living Didelphis marsupialis, or common opossum
Electron micrograph of a Discoaster alga
Fossilized axial skeleton of the Carboniferous-Permian amphibian Diplocaulus
Fossils of the Carboniferous crinoid ("sea lily") Dizygocrinus
Fossil of the Silurian-Late Devonian eurypterid ("sea scorpion") Drepanopterus
Fossils of the Cambrian-modern arthropod trackway ichnogenus Diplichnites
Shell in multiple views of a Dorsanum Nassa mud sea snail
Life restoration of the Early Cretaceous dromaeosaur ("raptor") Deinonychus
Underside of the reconstructed cranium of the Miocene baleen whale Diorocetus
Fossil shell of the Cretaceous-modern marine venus clam Dosinia
Fossilized leaves of the Carboniferous-Permian gymnosperm Dorycordaites
Restoration of the Eocene whale Dorudon
A living Donacia leaf beetle
Restoration of the Carboniferous Chimaera relative Delphyodontos
Illustration of the fossilized pygidium (tail segment) of the Cambrian trilobite Dikelocephalus
Fossilized skull of the Late Cretaceous tyrannosaur Daspletosaurus
Fossilized skeleton of the Late Cretaceous Alligator relative Deinosuchus
Fossilized skeleton of the Late Cretaceous marsupial relative Didelphodon
Restoration of the Late Jurassic long-necked dinosaur Diplodocus
Fossilized pelvis and tail of the Late Cretaceous armored dinosaur Dyoplosaurus
Foliage of a living Dalbergia retusa tree
Fossilized samara of the Eocene-modern Dipteronia tree
Illustration of a living Dicrostonyx torquatus, or Arctic lemming
A living Dipodomys, or kangaroo rat
Restoration of the Late Cretaceous marsupial relative Didelphodon
Fossilized skeleton of the Paleocene-Miocene crocodilian Diplocynodon
Restoration of the Late Cretaceous primitive tyrannosaur Dryptosaurus
Illustration of a fossilized tooth of the dubious Late Cretaceous reptile genus Diplotomodon
Fossilized skeleton of the Permian reptile relative Diadectes
Life restoration of the Permian reptile relative Diadectes
Fossilized skull of the Permian reptile relative Diadectes
Fossilized skeleton of the Permian synapsid (mammal precursor) Dimetrodon
Fossilized skull of the Permian synapsid (mammal precursor) Dimetrodon
Life restoration of the Permian synapsid (mammal precursor) Dimetrodon
Fossilized skull of the Late Triassic theropod dinosaur Daemonosaurus
Restoration of the Late Cretaceous tyrannosaur Daspletosaurus feeding on a horned dinosaur
Restoration of the Late Triassic reptile Doswellia
Restoration of the Late Triassic reptile Drepanosaurus
Fossil of the Carboniferous-Late Cretaceous petrified conifer wood morphogenus Dadoxylon
Fossil of the Silurian eurypterid ("sea scorpion") Dolichopterus
A living Dasyatis americana, or southern stingray
Shell of a Dermomurex murex sea snail
A living Dictyochales alga
Shell of a Dinocardium robustum, or Atlantic giant cockle
Shell exteriors and interiors of Donax fossor marine clams
Fossilized skeleton of the Triassic coelacanth Diplurus
Interpretive diagrams and fossils of a skull of the Permian primitive reptile Delorhynchus
Reconstructions of the youngest and most mature skulls of the Permian primitive reptile Delorhynchus
Dicranurus
Fossil of the Early Devonian trilobite Dicranurus
Fossilized skeleton of the Eocene pseudo-toothed bird Dasornis
A preserved Diacheila ground beetle
Restoration of the Middle Devonian lungfish Dipterus
Life restoration of the Permian amphibian Diploceraspis
Life restoration of a swimming group of the Permian amphibian Diploceraspis
A living Dendraster sand dollar
Restoration of the Late Cretaceous dromaeosaurid ("raptor") Dakotaraptor preying upon an ostrich dinosaur
Restoration of the Late Cretaceous primitive mosasaur Dallasaurus
Fossilized skeleton of the Late Triassic tuatara relative Diphydontosaurus
Living Diploastrea heliopora coral
Fossilized skeleton of the Late Cretaceous plesiosaur Dolichorhynchops
Shell of a Dreissena freshwater mussel
Fossilized shells of the Early Cretaceous ammonoid cephalopod Dufrenoyia
Restoration of the Permian amphibian Dasyceps
Fossilized skeleton of the Permian reptile relative Diadectes
Fossilized skull of the Permian reptile relative Diadectes
Fossilized partial skeleton of the Carboniferous amphibian Dissorophus
Fossilized skull of the Carboniferous amphibian Dissorophus
Fossilized skull of the Carboniferous amphibian Dissorophus
Restoration of the Late Cretaceous horned dinosaur Diabloceratops
A living Dendropanax
Illustration of a living Dicrostonyx, or collared lemming
Fossilized skeleton of the Early Cretaceous-Eocene bony fish Diplomystus preserved in the act of swallowing another fish
A living Distylium, or winter-hazel
A living Dolichopus fly
Flower of a living Drimys
Restoration of the Late Cretaceous tyrannosaur Daspletosaurus
Illustration of a fossil of the feeding burrow ichnogenus Diplocraterion. Rudolph Richter (1926)
Restoration of the Late Cretaceous "raptor" Dromaeosaurus
Restoration of the Silurian-Early Devonian primitive vascular plant Distichophytum
Fossilized skeleton of the Eocene brontothere mammal Diplacodon
A living Discus catskillensis land snail, or angular disc
A living Dryocopus pileatus, or pileated woodpecker
Divider

e==E==

  • Fossilized skeleton of the Pliocene-Pleistocene horse Equus simplicidens, also known as the Hagerman horse or American zebra
  • Fossilized shells and restored appearances of the Middle-Late Ordovician nautiloid cephalopod Endoceras
Fossilized shell of the Middle-Late Ordovician nautiloid cephalopod Endoceras
  • Fossil of the Silurian-Early Devonian eurypterid ("sea scorpion") Erettopterus
  • Restoration of the Silurian-Early Devonian eurypterid ("sea scorpion") Erettopterus
  • Illustration of fossils of various organs and stages of development of the Silurian-Early Devonian eurypterid ("sea scorpion") Erettopterus
  • Fossilized calyx of the Silurian-Middle Devonian crinoid ("sea lily") Eucalyptocrinites
  • Fossilized shell of the Silurian-Permian sea snail Euomphalus
  • Restoration of Silurian eurypterid ("sea scorpion") Eurypterus
  • Anatomy of the Silurian eurypterid ("sea scorpion") Eurypterus
  • Fossil of the Silurian eurypterid ("sea scorpion") Eurypterus
  • Fossil of the Middle-Late Devonian trilobite Eldredgeops
  • Fossilized holdfast of the Silurian-Middle Devonian crinoid ("sea lily") Eucalyptocrinites
  • Restoration of the Late Cretaceous armored dinosaur Edmontonia
  • Skeletal reconstruction and restored soft tissue of the Late Cretaceous duck-billed dinosaur Edmontosaurus regalis with an anachronistic human to scale
  • Restoration of the Early Cretaceous-Eocene bony fish Enchodus, or the "saber-toothed herring"
  • A living Equisetum, or horsetail
  • Restoration of the Late Cretaceous duck-billed dinosaur Eotrachodon
  • Illustration in multiple views of a fossilized shell of the Late Jurassic-Miocene nautiloid cephalopod Eutrephoceras
  • Interior of a fossilized shell of the Jurassic-Cretaceous foam oyster Exogyra
Fossil of the Middle Ordovician-Early Devonian trilobite Encrinurus
Cast fossils of the Devonian-modern sponge boring ichnogenus Entobia
Fossilized skull of the sea turtle Euclastes
Fossilized shell of the Late Cretaceous ammonoid cephalopod Eupachydiscus
Fossilized shell of the Late Cretaceous ammonoid cephalopod Exiteloceras
Illustration of a living Echinorhinus shark
A living Eleodes osculans, or wooly darkling beetle
A living Elgaria multicarinata, or southern alligator lizard
Restoration of two of the Eocene-Oligocene anthracothere mammal Elomeryx being menaced by fellow-anthracothere Anthracotherium
Restoration of the Oligocene-Miocene Enaliarctos and the toothed whale Macrodelphinus (background)
Interior of the shell of an Ensis, or razor clam
Fossilized skeleton of the Eocene-Pliocene frog Eopelobates
Underside of the fossilized cranium of the Eocene horse Epihippus
A living Epinephelus, a member of the family including sea basses and groupers
Shell in multiple views of an Epiphragmophora land snail
Restoration of the Pleistocene-Holocene Equus conversidens, or Mexican horse
Restoration of the Pleistocene bovid Euceratherium, or the shrub ox. Robert Bruce Horsfall (1913).
Living Eumetopias jubatus, or Steller's sea lions
A living Neverita lewisii, or Lewis's moon sea snail
A living Eutamias chipmunk
Restoration of the Late Devonian-Carboniferous Chimaera relative Edestus
Life restoration of the Carboniferous-Permian amphibian Eryops
Fossilized shell of the Eocene turtle Echmatemys
A living Ectobius wood cockroach
Fossilized skull of the Paleocene-Eocene mammal Ectocion


Restoration of the Paleocene mammal Ectoconus
Fossilized skeleton of the Paleocene mammal Ectoconus
Illustration of a living Eleodes, or Pinacate beetle
A living Empis daggerfly
A living Enochrus water scavenger beetle
Restoration of a pair of the Eocene uintathere mammal Eobasileus. Charles R. Knight (1890s).
Fossilized skeleton of the Eocene horse Eohippus
Restoration of the Eocene horse Eohippus. Heinrich Harder (1920).
Restoration of the Eocene brontothere mammal Eotitanops
Living member of the shrub genus Ephedra, which includes the joint-pines and Mormon tea
A living Epicauta blister beetle
Galls on a leaf caused by Eriophyes mites
A living Ethmia moth
Foliage and flowers of a living Eucommia tree
Branches and fruits of a living Eugenia
Fossil of the Eocene ant Eulithomyrmex
A living Euphorbia, or spurge
A living Tamias minimus (formerly Eutamias minimus), or least chipmunk
Restoration of the Late Triassic crocodile relative Erpetosuchus
Shell of an Echinocardium, or heart urchin
A living Echinometra lucunter, or rock boring urchin
A living Egretta thula, or snowy egret
Shell of an Engina sea snail
Illustration in multiple views of the shell of a Epitonium novangliae, or New England wentletrap
A living Equetus punctatus, or spotted drum
Fossilized skeleton of the Pliocene-Pleistocene ground sloth Eremotherium
A living Erethizon dorsatum, or North American porcupine
Photo of turtle swimming with extended flippers
A living Eretmochelys imbricata, or hawksbill sea turtle
A living Eubalaena, or Right whale
A living Eucidaris tribuloides, or slate pencil urchin
A living Eudocimus albus, or American white ibis
A living Euglandina rosea, also known as the rosy wolfsnail or the cannibal land snail
A living Plestiodon fasciatus, or American five-lined skink
A living Eumops glaucinus, or Wagner's bonneted bat
A living Euphagus cyanocephalus, or Brewer's blackbird
Shell of a Euvola raveneli, or Ravenel's scallop
Fossil of the Late Devonian-Carboniferous Chimaera relative Edestus
Fossilized skeleton of the Carboniferous-Permian bony fish Elonichthys
Fossilized skeleton of the Carboniferous-Permian bony fish Elonichthys
Illustration of fossil of the Carboniferous millipede Euphoberia
Fossilized calyx and partial stem of the Carboniferous crinoid ("sea lily") Eretmocrinus
Fossils (figures 2-10) of the Silurian-Devonian eurypterid ("sea scorpion") Erieopterus
Fossilized skeleton and interpretive diagram of the Carboniferous synapsid (mammal precursor) Eocasea
Restoration of the Carboniferous synapsid (mammal precursor) Eocasea
Fossilized skull and interpretive diagram of the Carboniferous synapsid (mammal precursor) Eocasea
Fossilized skeleton of the Carboniferous amphibian Eoscopus
Fossilized partial skeleton of the Late Cretaceous mosasaur Ectenosaurus
Restoration of the Late Cretaceous plesiosaur Elasmosaurus with an anachronistic human to scale
A living Eumeces skink
Illustration of a shell in multiple views of the Late Jurassic-Miocene nautiloid cephalopod Eutrephoceras
Fossils of the Devonian-modern borehold ichnogenus Entobia in a quahog shell
Fossilized cranium in multiple views of the Paleocene-Eocene gavial relative Eosuchus
Life restoration of the Miocene whale Eurhinodelphis (above)
Fossils of the large theropod dinosaur footprint ichnogenus Eubrontes
Fossil of the Early-Middle Ordovician cystoid echinoderm Echinosphaerites
Fossil of the crustacean Eryma
Fossilized shell of the Jurassic-Cretaceous foam oyster Exogyra
Illustration of a living Esox lucius, or northern pike
Interior of the shell of an Ensis leei, or Atlantic jackknife clam
Life restoration of the Late Cretaceous plesiosaur Edgarosaurus
Restoration of the Late Cretaceous duck-billed dinosaur Edmontosaurus annectens
Restoration of the Late Cretaceous horned dinosaur Einiosaurus
Restoration of the Late Cretaceous armored dinosaur Euoplocephalus
Restoration of the Eocene-Oligocene anthracothere mammal Elomeryx
Fossilized fruit of the Eocene Eucommia montana plant
Foliage and fruit of a modern Euonymus
A living Emys blandingii, or Blanding's turtle
Restoration of the Miocene elephant relative Eubelodon
Illustration with inset cross-section diagrams of the Cambrian sponge Ethmophyllum
Fossils of the Middle Triassic crinoid ("sea lily") Encrinus
Diagram of the anatomy of the Middle Triassic crinoid ("sea lily") Encrinus
Restoration of the Late Cretaceous plesiosaur Elasmosaurus
Fossilized shell in multiple views of the Late Cretaceous-Paleocene sea urchin Echinocorys
Illustration of a fossilized shell of the Eocene-Pliocene murex sea snail Ecphora
Fossilized skull of the Eocene sea turtle Eosphargis
Fossilized skeleton of the Carboniferous-Permian synapsid (mammal precursor) Edaphosaurus
Diagram illustrating the size of the Carboniferous-Permian synapsid (mammal precursor) Edaphosaurussize, compared to a human.
Illustration in multiple views of a fossilized skull of the Carboniferous-Permian synapsid (mammal precursor) Edaphosaurus
Restoration of the Carboniferous-Permian synapsid (mammal precursor) Edaphosaurus
Fossilized skeleton of the Carboniferous-Permian amphibian Eryops
Restoration of the Late Triassic distant crocodilian relative Effigia
Fossilized mandible in multiple views of the Late Cretaceous mammal Eodelphis
Diagram illustrating the size of average (orange) and record-setting (green) specimens of the Silurian eurypterid ("sea scorpion") Eurypterus, with an anachronistic human to scale
Fossil of the Silurian eurypterid ("sea scorpion") Eurypterus
A living Eudocimus ibis
Life restoration of the Permian lobe-finned fish Ectosteorhachis
Fossilized skeleton of the Permian lobe-finned fish Ectosteorhachis
Restoration of the Carboniferous-Permian synapsid (mammal precursor) Edaphosaurus
Replica fossilized skull of the Carboniferous-Permian amphibian Eryops
Restoration of the Permian synapsid (mammal precursor) Edaphosaurus
Fossils at different stages of development of the Cambrian trilobite Elrathia
Shell of a Eucrassatella speciosa, or Gibbs' clam
Fossilized mandible of the Eocene-Oligocene false saber-toothed cat Eusmilus
A living Eremophila alpestris, or horned lark
A living Eleutherodactylus, or rain frog
Living Ellisella coral, or sea whips
Fossilized skeleton of the Carboniferous-Permian synapsid (mammal precursor) Edaphosaurus
Restoration of the Carboniferous-Permian synapsid (mammal precursor) Edaphosaurus
Restoration of the Carboniferous-Permian synapsid (mammal precursor) Edaphosaurus
Fossilized skeleton of the Carboniferous-Permian synapsid (mammal precursor) Edaphosaurus
Restoration of the Permian amphibian Edops
Fossilized skull in multiple views of the Permian reptile Eothyris
Life restoration of the Permian reptile Eothyris
Shell of an Epitonium sea snail, or wentletrap
Fossils of the Cambrian-Middle Ordovician echinoderm relative Eldonia
Fossil of the Cambrian arthropod Emeraldella
Illustration of a reconstructed skull and restorative portrait of the Late Cretaceous primitive duck-billed dinosaur Eolambia
Fossil of the Eocene bee Euglossopteryx
Fossil of the Cambrian trilobite Ellipsocephalus
Restoration of the Cambrian-Early Ordovician trilobite Entomaspis
Restoration of the Cambrian echinoderm relative Eocystites
Diagram illustrating the size of the Late Jurassic ceratosaur Elaphrosaurus with an anachronistic human to scale
Fruit and foliage of a living Elaeodendron
Illustration of a living Esox, the genus including pikes and pickerels
Illustration of a fossilized shell of the Miocene murex sea snail Ecphora gardnerae
Restoration of two of the Miocene baleen whale Eobalaenoptera pursued by the giant shark Carcharocles megalodon
A living Esox americanus, or American pickerel
Divider
  • A living Ficus, or fig tree
  • Fossil of the Late Ordovician-Permian tabulate coral Favosites
  • Front (left) and right side (right) views of an enrolled fossil of the Middle Ordovician-Silurian trilobite Flexicalymene
  • Assemblage of fossils of Silurian-Permian fusulinid foraminiferans
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Fagesia
  • Fossilized shell of the Cretaceous-modern spindle sea snail Fusinus
  • A living Falco sparverius, or American kestrel
  • Shell of a Fissurella keyhole limpet
  • Fossil in multiple views of the Late Devonian-Permian tabulate coral Favosites
  • Fossilized foliage of the Cretaceous-Oligocene flowering plant Flabellaria
Illustration of a fossil of the Cambrian trilobite Fallotaspis
Modern shell of a Fissurella keyhole limpet
A living Falco peregrinus, or peregrine falcon
Fossilized shell of the Oligocen-modern scallop Flabellipecten
Flower of a Forestiera, or swampprivets
A living Fragilaria diatom
A living Fratercula cirrhata, or tufted puffin
A living Fulica americana, or American coot
A living Falcipennis grouse
Fossilized flower of the Eocene-Oligocene rose relative Florissantia
A living Formica, or wood ant
A living Fulgora planthopper
A living Falco columbarius, or merlin
A living Farancia abacura, or mud snake
A living Fasciolaria tulipa, or true tulip sea snail
A living Felis, or cat
Fruit and foliage of a living Ficus carica, or Common fig
A living Egretta caerulea, or little blue heron
Shell of a Fragum cockle
Shell in multiple views of a Fulguropsis whelk
A living Fundulus
Illustrations of the flowers and foliage of a living Fraxinus, or ash tree, with insets further detailing its anatomy
Fossil of the Middle Ordovician-Late Triassic bryozoan ("moss animal") Fenestella
Collection of fossils of Silurian-Permian fusulinid foraminiferans
Electron micrograph of a fossil of a Silurian-Permian fusulinid foraminiferan
Fossilized calyx of the Devonian-Carboniferous crinoid ("sea lily") Forbesiocrinus
Living Fistulobalanus barnacles
Restoration of the Permian Chimaera relative Fadenia
Fossil of the Middle Ordovician-Silurian trilobite Flexicalymene
Life restorations of a female (top) and male (bottom) of the Carboniferous Chimaera relative Falcatus
A living Fokienia cypress tree
Shell of a Fasciolaria, or tulip sea snail
Fossilized shell of the Late Cretaceous ammonoid cephalopod Fagesia superstes
A living Falco mexicanus, or prairie falcon
Illustrations of fossilized shells of the Cambrian marine bivalve Fordilla
A living Fratercula arctica, or Atlantic puffin
Restoration of the Permian amphibian Fayella preying upon a Varanodon
Fossilized skull in multiple views of the Permian primitive reptile Feeserpeton
Fossil in an enrolled posture of the Late Ordovician trilobite Frencrinuroides
A living Fothergilla, or witch alder
A living Fusconaia freshwater mussel
Living Favia stony coral
Living Favia coral
Fossilized skeleton of the Early Cretaceous therizinossaur Falcarius
A living Falco rusticolus, or gyrfalcon
Fossilized skeleton of the Eocene bird Fluvioviridavis
Known material diagram of the Late Jurassic ceratosaur Fosterovenator
Divider
  • Fossilized shell of a Glycymeris, or bittersweet clam
  • Fossilized calyx and partial stem of the Devonian-Carboniferous crinoid ("sea lily") Gilbertsocrinus
  • Assemblage of fossils of the Middle Ordovician-Silurian crinoid ("sea lily") Glyptocrinus
  • Multiple views of a fossil of the Ordovician horn coral Grewingkia
  • Fossilized shell of the Cretaceous ammonoid cephalopod Gaudryceras
  • Fossilized skull of the Late Jurassic sauropod dinosaur Galeamopus
  • Fossilized skull and shell of the Late Jurassic-Early Cretaceous turtle Glyptops
  • Restoration of the Late Jurassic-Early Cretaceous crocodile relative Goniopholis
  • Fossilized shell of the Carboniferous-Eocene bivalve Gervillia
  • Life restoration of the Late Cretaceous mosasaur Globidens
  • Illustration of a reconstructed skull of the Late Cretaceous mosasaur Globidens
  • Fossilized shells of Glycymeris, or bittersweet clams
  • Life restoration of the Carboniferous shark Glikmanius
  • Fossilized tooth of the Carboniferous shark Glikmanius
  • Life restoration of the Permian lungfish Gnathorhiza
  • Fossilized leaves of the Jurassic Ginkgo huttonii tree
  • Restoration of a herd of the Pliocene-Holocene ground sloth Glossotherium
  • Fossilized skeleton of the Pleistocene armadillo relative Glyptotherium
Fossil of the bore-hole ichnogenus Gastrochaenolites (G)
Fossil of the Silurian trilobite Glyptambon
Fossil of the Carboniferous ammonoid cephalopod Goniatites crenistria
Restoration of the Cambrian echinoderm Gogia
Fossil of the theropod dinosaur footprint ichnogenus Grallator
Fossil negative with skin impressions of the theropod dinosaur footprint ichnogenus Grallator
Fossil of the theropod dinosaur footprint ichnogenus Grallator
A living Galeocerdo cuvier, or tiger shark
A school of living Gasterosteus aculeatus, or three-spined stickleback
Living adult and young Gavia stellata, or red-throated loon
A living Geococcyx californianus, or greater roadrunner
A living Gerrhonotus, or alligator lizard
A living Glaucidium gnoma, or mountain pygmy owl
Living Globularia, or globe daisies
Restoration of the Miocene walrus Gomphotaria
Fossilized skeleton of the Miocene-Pleistocene elephant relative Gomphotherium
A living Gopherus, or desert tortoise
A living Gymnogyps californianus, or California condor
A living Gaurotes longhorn beetle
A living Geomys bursarius, or Plains pocket gopher
Illustration of a living Glossina, or tsetse fly
Fossilized foliage of the cypress relative Glyptostrobus
A living Gorytes sand wasp
Fossil of the Eocene lace bug Gyaclavator
A living Gallinago gallinago, or common snipe
A living Gambusia affinis, or mosquitofish
A living Gastrophryne carolinensis, or the eastern narrow-mouthed toad
Fossilized skull of the Miocene crocodile relative Gavialosuchus
A living Geochelone tortoise
A living Geranoaetus bird of prey
Shell of a Gibberula sea snail
Fossilized shells of the Oligocene-Pliocene scallop Gigantopecten
A living Glaucomys, or New World flying squirrel
A living Glaucomys sabrinus, or northern flying squirrel
Illustration of a living Globicephala macrorhynchus, or short-finned pilot whale
Shell of a Glyphostoma sea snail
A living Gopherus polyphemus, or gopher tortoise
A living Graptemys barbouri, or Barbour's map turtle
A living Grus americana, or whooping crane
Fossil of the Cambrian echinoderm Gogia
Fossil of the Cambrian echinoderm Gogia
Fossil of the Middle-Late Devonian trilobite Greenops
Fossilized skeleton of the Carboniferous four-limbed animal precursor Greererpeton
Restoration of the Carboniferous four-limbed animal precursor Greererpeton
Fossils of the Middle Ordovician-Early Devonian trilobite Gravicalymene
Restoration of the Late Cretaceous bony fish Gillicus
A living Gopherus, or gopher tortoise
Illustration of shells of deceased Globigerina and related foraminiferans as seafloor "Globigerina ooze"
This shaded bog turtle specimen is resting in the palm of a person's hand, highlighting its petite size.
A living Glyptemys muhlenbergii, or bog turtle
A living Gulo gulo, or wolverine
Fossilized leaf of the Permian-modern tree Ginkgo
Fossilized skeleton of the Middle Jurassic-Late Cretaceous mammal Gobiconodon
Life restoration of the Late Cretaceous tyrannosaur Gorgosaurus
Restoration of the Late Cretaceous duck-billed dinosaur Gryposaurus
A living Gaillardia, or blanket flower
Fossilized head of the Cambrian trilobite Glyptagnostus
Fossil of the Cambrian trilobite Glyptagnostus
Fossilized shell of the Triassic ammonoid cephalopod Gymnites
Life restoration with inset scale diagram of the bird Gastornis
Fossil tube of the Jurassic-modern polychaete worm Glomerula
Restoration of the Late Triassic theropod dinosaur Gojirasaurus
Fossilized shell of the Middle Ordovician-Middle Devonian nautiloid cephalopod Geisonoceras
Fossilized shell of the Middle Devonian nautiloid cephalopod Goldringia
Illustration of a living Gadus morhua, or Atlantic cod
A living Globicephala, or pilot whale
Fossilized foliage of the Early Cretaceous-Pleistocene conifer Glyptostrobus europaeus
Various conodont elements, including those of Gnathodus (specimens 9 and 12)
Fossilized teeth of the conodont Gnathodus
Fossils of the Carboniferous coral Gymnophyllum, also known as button coral
Fossil of the Cambrian trilobite Genevievella
A living Graptemys, or map turtle
Shell of a Gastrocopta armifera land snail, or armed snaggletooth
Restoration of the Pleistocene armadillo relative Glyptodon
Restorative portrait of the Eocene-Oligocene bear dog Gustafsonia
Restorative portrait of the Late Cretaceous duck-billed dinosaur Gryposaurus.
Restoration of the Permian frog precursor Gerobatrachus
Fossilized shell of the Carboniferous-Permian brachiopod Gypospirifer condor
Illustration of a living Galerita ground beetle
Fossilized skeleton of the Eocene bird Gallinuloides
Fossilized skull of the Late Jurassic long-necked dinosaur Galeamopus
Fossilized skeleton of the Late Jurassic armored dinosaur Gargoyleosaurus
A living Gyrinophilus porphyriticus, or Spring salamander
Restoration of the Middle Devonian-Carboniferous acanthodian ("spiny shark") Gyracanthus
Fossilized skeletons of the Early Cretaceous armored dinosaur Gastonia
Fossilized skeleton of the Late Cretaceous duck-billed dinosaur Gryposaurus
Illustration of a living Gadus, or cod
Illustration of a living Geomys, or eastern pocket gopher
Divider
  • Two modern shells, closed (left) and open (right), of Hiatella arctica, also known as the wrinkled rock-borer
Life restoration of a herd of the Miocene-Pleistocene horse Hipparion. Heinrich Harder (1920).
  • Fossil of the Ordovician bryozoan ("moss animal") Hallopora
Close-up photograph of a fossil of the Ordovician bryozoan ("moss animal") Hallopora
  • Fossil of the Ordovician-Silurian tabulate coral Halysites
Thin-section view of a fossil of the Ordovician-Silurian tabulate coral Halysites
  • Fossilized shell of the Silurian mollusc Helcionopsis
  • Fossil of the Middle Devonian horn coral Heliophyllum
  • Fossil of the Devonian colonial rugose coral Hexagonaria, also known as a Petoskey stone
  • Fossilized shells of the Ordovician-Carboniferous sea snail Holopea
  • Fossilized shells of the Cambrian-Permian brachiopod relative Hyolitha
Fossilized shells of the Cambrian-Permian brachiopod relative Hyolitha
  • Restoration of the Late Jurassic crocodile relative Hallopus
  • Life restoration of the Late Jurassic sauropod dinosaur Haplocanthosaurus
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Herrickiceras
  • Restoration of the Late Cretaceous mosasaur Halisaurus
  • Restoration of two of the Late Cretaceous mosasaur Eonatator
  • Fossilized skeleton of the Cretaceous bony fish Hoplopteryx
  • Restoration of two of the Permian-Late Cretaceous cartilaginous fish Hybodus
  • Fossilized skeleton of the Late Cretaceous toothed bird Hesperornis
  • Restoration of the Late Cretaceous toothed bird Hesperornis
  • Illustrations of fossils of the Late Triassic hydrozoan Heterastridium
  • Fossilized skull of the Middle Triassic amphibian Hadrokkosaurus
  • Life restoration of the Late Triassic crocodile relative Hesperosuchus
  • Restoration of Pliocene-Pleistocene Homotherium, or scimitar cat
Fossilized shell of the Late Cretaceous ammonoid cephalopod Hoploscaphites
Restoration of the Permian Chimaera relative Helicoprion
A living Haliotis, or abalone
The iridescent interior of a shell of a Haliotis, or abalone
Fossilized shell of the Late Cretaceous ammonoid cephalopod Hauericeras
Fossilized shell of the Triassic ammonoid cephalopod Hedenstroemia
Fossilized shell of the Middle Jurassic-Early Cretaceous sea urchin Hemicidaris
Fossilized teeth of the Cretaceous-modern cow shark genus Heptranchias
Fossilized skeleton of the Permian-Late Cretaceous shark Hybodus
Fossilized skeleton of the Permian-Late Cretaceous shark Hybodus
A living Haminoea bubble sea snail
Fossilized skull of the mesonychian mammal Harpagolestes
A living Heloderma, the genus including the Gila monster and beaded lizards
Fossilized skeleton of the Eocene-Miocene mammal Herpetotherium
Life restoration of the Eocene-Miocene mammal Herpetotherium
A living Calomys (formerly Hesperomys), or vesper mouse
A living Hexagrammos greenling
Illustration of a living Hexanchus, or sixgill shark
Restoration of a herd of the Pliocene-Holocene horse Hippidion. Robert Bruce Horsfall (1913).
Restoration of the Eocene-Miocene creodont mammal Hyaenodon
Life restoration of the Miocene horse Hypohippus. Heinrich Harder (1920).
Flowers of a living Halesia, or silverbell
Restoration of the Paleocene-Eocene mesonychian mammal Hapalodectes (below)
Restoration of the Paleocene-Eocene mesonychian mammal Hapalodectes
Illustration of a living Hellwigia wasp (upper left)
Two living Helophorus beetles
Restoration of the Eocene tapir relative Heptodon
A living Heriades mason bee
Life restoration of Hesperocyon
A living Heterodon nasicus, or Western hognose snake
Heyderia fungus growing among moss
Fossilized skull of the Eocene tapir-like mammal Homogalax
Diagram illustrating the life cycle of a Hoplocampa sawfly
Living Hydrangea flowers
A living Hydrobius fuscipes water scavenger beetle
A living Hygrotus predaceous diving beetle
A living Hylobius weevil
Life restoration of the Eocene odd-toed ungulate Hyopsodus
Fossilized skeleton of the Eocene odd-toed ungulate Hyrachyus
Restoration of the Eocene-Oligocene odd-toed ungulate Hyracodon. Charles R. Knight (1896).
Restoration of the Late Triassic reptile Hypsognathus.
Fossilized teeth of the Miocene weasel shark Hemipristis serra
A living Halichoeres wrasse
Living Halimeda green algae
A preserved Heliaster microbrachius sea star
A living Heterodon simus, or southern hognose snake
A living Himantopus, or stilt
Fossilized skeleton of the Miocene-Pliocene horse Hippotherium
Restoration of the Pleistocene armadillo relative Holmesina with a human to scale
Shell of a Hyalina margin sea snail
A living Hydrochoerus, or capybara
Life restoration of the Cambrian brachiopod relative Haplophrentis
Fossilized shells of the Cambrian brachiopod relative Haplophrentis
Fossils of the burrow ichnogenus Helminthopsis
Fossils of the burrow ichnogenus Helminthopsis
Living Hypoxylon fungus
Fossil of the Jurassic-Paleogene lobster Hoploparia
A living Pseudacris crucifer (formerly Hyla crucifer), or spring peeper
Fossil of the Cambrian mollusc Halkieria.
Illustration of a fossilized partial cranium of the Eocene odd-toed ungulates Hyracotherium
Shells of Helisoma anceps, or two-ridge rams-horn freshwater snails
Restoration (bottom) of the Carboniferous "antlered" Chimaera relative Harpagofututor
Fossilized tooth-whorl of the Carboniferous Chimaera relative Helicoprion
Fossilized skeleton of the Late Cretaceous duck-billed dinosaur Hypacrosaurus
Life restoration of the Late Cretaceous duck-billed dinosaur Hypacrosaurus
Fossilized skull of the Oligocene lizard Helodermoides
Illustration of a living Hiodon, or mooneye
Foliage and flowers of a living Holmskioldia or Chinese hat plant
Fossilized skeleton of the Eocene-Miocene even-toed ungulate Hypertragulus
Life restoration of the Eocene-Oligocene false saber-toothed cat Hoplophoneus. Robert Bruce Horsfall (1913).
Restoration of the Carboniferous Chimaera relative Helicoprion
Replica of the fossilized tooth whorl of the Carboniferous Chimaera relative Helicoprion
Fossilized tooth whorl of the Carboniferous Chimaera relative Helicoprion
Restoration of the Middle Ordovician trilobite Hypodicranotus
Fossil of the Cambrian trilobite Holmia. Kiaer (1916).
Life restoration of the Late Cretaceous duck-billed dinosaur Hadrosaurus
Life restoration of the Late Triassic primitive reptile Hypsognathus
Life restoration of the Late Triassic drepanosaur Hypuronector
Restoration of the Late Devonian eurypterid ("sea scorpion") Hallipterus
Life restoration of the Late Devonian eurypterid ("sea scorpion") Hallipterus
Fossil of the Silurian eurypterid ("sea scorpion") Hardieopterus
Fossil of the Late Ordovician-Middle Devonian Homalonotus
Restoration in multiple views of the Silurian eurypterid ("sea scorpion") Hughmilleria
Restoration of the Silurian eurypterid ("sea scorpion") Hughmilleria
Fossils of the Silurian eurypterid ("sea scorpion") Hughmilleria
Texas City Dike, Texas
A living Haematopus palliatus, or American oystercatcher
A living Heliornis fulica, or Sungrebe
A living Histrionicus histrionicus, or harlequin duck
Fossilized vertebra of the Late Cretaceous duck-billed dinosaur Hypsibema
A living Humulus, or hop plant
Life restoration of the Eocene-Oligocene dog Hesperocyon. Robert Bruce Horsfall (1913).
Fossil of the Early Devonian trilobite Huntoniatonia
Fossilized mandible of the Eocene horse Haplohippus
Fossil of the Cambrian sponge Hazelia
Restoration of the Middle-Late Devonian placoderm fish Holonema
Fossil of the Late Devonian-Carboniferous lobe-finned fish Holoptychius
Restoration of the Late Devonian four-limbed animal precursor Hynerpeton
A living Halichoerus grypus, or grey seal
Restoration of the Eocene-Oligocene manatee relative Halitherium
Life restoration of the Late Cretaceous mosasaur Hainosaurus
Fossilized skeleton of the Early Jurassic bony fish Hulettia
Illustration in multiple views of a fossilized shell of the Silurian mollsuc Helcionopsis striata
Fossil of the Cretaceous-Miocene crab Harpactocarcinus
Life restoration of the Pleistocene pronghorn Hayoceros
Shell of Haminoea bubble shell sea snail
Illustration in multiple views of fossilized shells of the Late Cretaceous ammonoid cephalopod Didymoceras navarroensis
A living Homarus lobster
Fossil of the Late Cretaceous lobster Hoploparia bearpawensis
Living Hydnophora coral
Fossil of the Permian worm-like possible mollusc Helicoconchus
Assemblage of fossils of the Permian worm-like possible mollusc Helicoconchus
Fossilized shells of the Cambrian brachiopod relative Haplophrentis
Life restoration of the Late Cretaceous oviraptorosaur Hagryphus
Restoration of the Early Cretaceous Iguanodon relative Hippodraco
Life restoration of the Late Jurassic crocodilian relative Hoplosuchus
Known material diagram of the Middle-Late Triassic distant crocodilian relative Heptasuchus
Restoration of the Late Jurassic stegosaur Hesperosaurus
Restoration of the Late Triassic rhynchosaur Hyperodapedon
Fruit of a Hovenia tree
A living Hydrobius water scavenger beetle
Restoration of the Eocene odd-toed ungulate Hyrachyus
Life restoration of the Late Cretaceous ammonoid cephalopod Hamites
Divider
  • Branches of a living Ilex opaca, or American holly, full of ripe fruit
  • A modern Isurus, or mako shark
  • Restoration of the Permian amphibian Isodectes
  • Fossil of the Middle-Late Ordovician giant trilobite Isotelus.
  • Fossil of the Ordovician crinoid ("sea lily") Iocrinus
  • Fossilized shell of the Early Jurassic-Late Cretaceous marine bivalve Inoceramus with a human indicating its size
  • Restoration of the Late Cretaceous toothed bird Ichthyornis
  • Fossilized shell of the Permian-modern marine bivalve Isognomon
  • Illustrations at different scales of fossils of the Jurassic-Cretaceous coral Isastrea
  • Fossilized skull of the Miocene bear Indarctos
A living Iridomyrmex, or rainbow ant
Fossil of the Middle Ordovician trilobite Illaenus
Diagram illustrating two specimens of the Late Cretaceous toothed bird Ichthyornis with an anachronistic human to scale
Restoration of a pod of the Late Triassic-Early Jurassic ichthyosaur Ichthyosaurus
Living Isognomon marine bivalves
Restoration of the Miocene walrus Imagotaria
Fossilized skeleton of the Eocene-Oligocene rodent Ischyromys
A living Isurus oxyrinchus, or shortfin mako shark
Foliage and fruit of a living Ilex, or holly
Fossilized skull of the Eocene-Oligocene rodent Ischyromys
A living Isomira comb-clawed beetle
Illustration of a living Ameiurus catus (formerly Ictalurus catus), or white bullhead
A living Ixobrychus exilis, or least bittern
Life restoration of the Carboniferous Chimaera relative Iniopteryx
Fossil of the Middle-Late Ordovician trilobite Isotelus.
Restoration of the Carboniferous synapsid (mammal precursor) Ianthasaurus
Illustration of a living Ameiurus melas (formerly Ictalurus melas), or Black bullhead
Illustration of a living Ictiobus, or buffalo fish
Illustration of a living Ictalurus catfish
Fossilized skeleton of the Middle Jurassic-Miocene Chimaera relative Ischyodus
Shells of Ischadium recurvum, or hooked mussels
Diagram illustrating the anatomy of a living Isoetes, or quillwort
Restoration of the Late Triassic gliding reptile Icarosaurus
Fossilized teeth of the Late Cretaceous-modern Isurus, or mako shark
Shells of Tritia trivittata threeline mud sea snail
A modern Isistius dogfish
A living Istiophorus platypterus, or Indo-Pacific sailfish
Fossilized shell of the Late Jurassic ammonoid cephalopod Idoceras
Known material diagram of the Early Cretaceous Iguanodon relative Iguanacolossus
Restoration of the Early Cretaceous Iguanodon relative Iguanacolossus
Fruit of a living Illicium, or star anise
Fossilized skeleton of the Eocene bat Icaronycteris
Fossilized shells of the Silurian nautiloid cephalopod Inversoceras
A living Icterus spurius, or orchard oriole
A living Istiophorus , or sailfish
Divider
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Jeletzkytes
Living Juncus, or rushes
A living Juniperus, or juniper tree
A living Juglans, or walnut tree
A living Junco hyemalis, or dark-eyed junco
A living Jabiru mycteria stork
A living Jordanella floridae, or American flagfish
Restoration of the Carboniferous-Permian ray-like cartilaginous fish Janassa (top and left)
Life restoration of the Late Cretaceous horned dinosaur Judiceratops
A living Juglans regia also known as the Persian or English walnut
Restoration of the Late Cretaceous primitive duck-billed dinosaur Jeyawati
A living Juniperus virginiana, also known as red cedar or eastern juniper
Fossilized skeleton of the Eocene wading bird Juncitarsus
Divider
  • A living Koelreuteria tree
  • Illustration of a fossilized shell of the brachiopod Kutorgina
  • Fossilized shells of the Middle Ordovician-Permian nautiloid cephalopod Kionoceras
  • Fossil of the Late Jurassic horseshoe crab Mesolimulus at the end of the trackway that it produced of the ichnogenus Kouphichnium
  • Fossilized "worm" tube, possibly of the Oligocene-modern shipworm marine bivalve genus Kuphus
  • Fossil of the Cambrian trilobite Kootenia
  • Assemblage of partial fossils of the Cambrian trilobite Kootenia
  • Fossilized shell of the Middle Jurassic ammonoid cephalopod Kepplerites
  • Fossilized shell of the Middle Jurassic ammonoid cephalopod Kosmoceras
  • Fossilized shell of the Middle Jurassic ammonoid cephalopod Kosmoceras spinosum
  • Restoration of the Early Jurassic turtle Kayentachelys
  • Fossilized skull of the Early Jurassic synapsid (mammal precursor) Kayentatherium
  • Life restoration of the Early Jurassic theropod dinosaur Kayentavenator
Fossilized shells of the Jurassic brachiopod Kallirhynchia
Fossilized shell of the Early Cretaceous ammonoid cephalopod Kossmaticeras
Shell in multiple views of a Kelletia kelletii, or Kellet's whelk
Restoration of the Oligocene-Miocene dolphin Kentriodon
Close-up of the tip of a branch of a Keteleeria conifer tree
Flowers of a living Kalmia shrub
A living Kinosternon subrubrum, or eastern mud turtle
Shell of a Kurtziella cerina sea snail
Restoration of the Silurian eurypterid ("sea scorpion") Kokomopterus
Phosphate nodules containing fossils of the Carboniferous Chimaera relative Kawichthys
A living Kinosternon flavescens, or yellow mud turtle
Fossil of the Cambrian trilobite Kendallina
Restoration of the Late Cretaceous duck-billed dinosaur Kritosaurus
Restoration of the Oligocene-Miocene horse Kalobatippus
Restoration of the Late Triassic amphibian Koskinonodon
Illustration of a modernKogia breviceps, or pygmy sperm whale
A living Kajikia albida, or white marlin
Fossils of the Early Devonian trilobite Kainops
Fossilized heads of the Silurian eurypterid ("sea scorpion") Kiaeropterus (specimens 1-8)
Shells of Kurtziella sea snails
Fossilized skeleton of the Late Triassic amphibian Koskinonodon
Life restoration at various ages of the Late Triassic amphibian Koskinonodon with an anachronistic human to scale
Diagram illustrating the size of the Late Jurassic long-necked dinosaur Kaatedocus with an anachronistic human to scale
Fossilized skeleton of the Eocene bony fish Knightia
Restoration of the Late Cretaceous horned dinosaur Kosmoceratops
Divider
  • Two views of a shell of a Latirus sea snail
  • The autumn foliage of a living Liquidambar, or sweetgum tree
  • A living Lynx
  • Fossilized strobilus (cone-like reproductive structure) of the Carboniferous tree-sized club moss relative Lepidodendron
  • Life restoration of the Carboniferous tree-sized club moss relative Lepidodendron
  • Fossilized skull of the Carboniferous tetrapod Loxomma
Life restoration of the Carboniferous tetrapod Loxomma
  • External mold fossil of the Carboniferous tree-sized club moss relative Lepidodendron
  • Illustration of a living Lepisosteus, or gar
  • Restoration of a school of the Middle Triassic-Early Cretaceous bony fish Leptolepis
  • Restoration of a school of the Middle Triassic-Early Cretaceous bony fish Leptolepis
  • Restoration of the Carboniferous-Late Triassic club moss relative Lepidodendron. Eli Heimans (1911).
  • Illustration of a fossilized shell of the Cambrian-Late Ordovician brachiopod Lingulella
  • Shell of a Lithophaga, or date mussel
  • Fossilized shell of the Triassic-modern marine bivalve Lopha
  • Illustration of a fossilized skull of the Late Cretaceous duck-billed dinosaur Lophorhothon
  • Fossilized shell of the Early Jurassic-Late Cretaceous ammonoid cephalopod Lytoceras
  • Fossilized shell of the Middle Jurassic ammonoid cephalopod Lytoceras eudesianum
  • Fossilized shell of the Middle Jurassic ammonoid cephalopod Lytoceras fimbriatum
  • Fossilized skull of the Late Triassic phytosaur Leptosuchus
  • Electron micrograph of fossilized teeth from the Early Jurassic-Early Cretaceous freshwater shark Lissodus
A living Lepus alleni, or antelope jackrabbit
Fossil of the Ordovician trilobite Lonchodomas
Fossil of the Ordovician trilobite Lonchodomas
Fossilized shell of the Cretaceous ammonoid cephalopod Lytoceras batesi
Shell in multiple views of a Labyrinthus land snail
Shell of a Laevicardium elatum, or giant egg cockle
Living Lagenorhynchus dolphins
Restoration of the Miocene opah fish Lampris zatima
A living Larus californicus, or California gull
A living Atractosteus spatula (formerly Lepisosteus spatula), or alligator gar
Illustration of a fossilized skull of the Oligocene-Miocene dog Leptocyon
Restoration of the Eocene-Oligocene even-toed ungulate Leptomeryx
A living Leptopecten latiauratus, or kelp scallop
A living Lepus americanus, or snowshoe hare
Lepus californicus, or black-tailed jackrabbit
Top view of a fossilized skull of the Eocene creodont mammal Limnocyon
A living Limosa fedoa, or marbled godwit
A pod of living Lissodelphis borealis, or right whale dolphins
Life restoration of the Paleocene-Eocene bird Lithornis
A living Littorina scutulata periwinkle
Restoration of the Miocene marine drumfish Lompoquia
Restoration of the Miocene bluefish relative Lophar
Shell of a Lottia scabra, or rough limpet
Underside of a Luidia sea star
Fossilized skull of the Eocene carnivoran mammal Lycophocyon
Frond of a living Lygodium, or climbing fern
Restoration of the Permian reptile precursor Limnoscelis
A living Lagopus leucura, or white-tailed ptarmigan, in full summer plumage
A living Larus gull
A living Lasiopodomys vole
A living Lasius
A living Lebia, or colorful foliage ground beetle
Restoration of the Oligocene-Miocene oreodont mammal Leptauchenia
Restoration of the Oligocene-Miocene oreodont mammal Leptauchenia
Fossilized skeleton of the even-toed ungulate Leptomeryx
A living Leptostylus longhorn beetle
A living Lepus townsendii, or white-tailed jackrabbit
A living Limnephilus caddisfly
Berries and foliage of a living Lindera
Flowers of a living Linnaea
A living Linyphia sheet weaver spider
Preserved Liometopum ant
Restoration of the Eocene butterfly Lithodryas
Flowers of a living Lomatia
Illustration of various living flea beetles, including Longitarsus (first member of third row)
Pair of living Lontra canadensis, or North American river otter
A living Lycosa wolf spider
A living Lygaeus seed bug
A living Lytta blister beetle
A living Lachnolaimus maximus, or hogfish
A living Lagodon rhomboides, or pinfish
A living Lasiurus, or hairy-tailed bat
Illustration of a living Laterallus exilis, or grey-breasted crake
A living Leiostomus xanthurus, or spot
A living Leopardus pardalis, or ocelot
A living Leopardus wiedii, or margay
A living Lepidochelys, or ridley sea turtle
A living Limnodromus scolopaceus, or long-billed dowitcher
Shell of a Linatella triton sea snail
Shell of a Liotia sea snail
Shell of a Lithopoma americanum turban sea snail
A living Littoraria angulifera, or mangrove periwinkle
A living Lophodytes cucullatus, or hooded merganser
Shells of Lucapina sowerbii, or Sowerby's fleshy limpet
A living Lutjanus snapper
A living Lytechinus variegatus, also known as the green or variegated sea urchin
Fossil in cross section of the Carboniferous seed fern stem Lyginopteris
A living Lactophrys boxfish
A living Leopardus
Illustration of a fossil of the Carboniferous centipede Latzelia
Fossilized bark of the Carboniferous-Late Triassic club moss relative Lepidodendron, also known as the scale tree
Life restoration of the Permian snake-like amphibian Lysorophus showing speculative egg-coiling behavior
Restoration of the Carboniferous-Early Triassic cartilaginous fish Listracanthus
Illustration of a living Lepisosteus platostomus, or shortnose gar
A living Lepomis humilis, or orangespotted sunfish
Living Lactarius mushrooms
Shells in multiple views of Latiaxis coral sea snails
Fossilized skull and vertebrae of the Permian snake-like amphibian Lysorophus
Living Libinia crabs
Shell of a Limecola balthica, or Baltic clam
Fossilized skeleton of the Early Jurassic-Late Cretaceous bony fish Lepidotes
Restoration of the Late Cretaceous primitive horned dinosaur Leptoceratops
Fossilized foot bones of the Late Cretaceous oviraptorosaur Leptorhynchos
Fossilized skeleton of the Eocene-Oligocene Leptictis
A living Lepomis microlophus, or redear sunfish
Portrait living Lontra otters
Living Lycopodium, or ground pine clubmosses
Fossil of the Late Ordovician-Middle Devonian trilobite Leonaspis
Fossilized skull of the Late Cretaceous alligator relative Leidyosuchus
Partial fossilized jaws of the Late Cretaceous mosasaur Liodon
Illustration of a living Libinia emarginata, or portly spider crab
Living Lunularia, or crescent-cup liverwort
A living Loxia curvirostra, or red crossbill
Fossils of the Middle Devonian clubmoss Leclercqia
Restoration of the Early Ordovician nautiloid cephalopod Levisoceras
A living Leucophaeus atricilla, or laughing gull
Mounted skeleton of a Lophius americanus, or American anglerfish
A living Lopholatilus chamaeleonticeps, or great northern tilefish
Life restoration of the Permian reptile Labidosaurikos
Life restoration of the Permian reptile Labidosaurus
Fossilized skeleton of the Permian reptile Labidosaurus
Life restoration of the Permian amphibian Llistrofus
Fossilized shell of the Early Cretaceous ammonoid cephalopod Lyelliceras
Illustration of shells in multiple views of Lacuna vincta, or northern lacuna sea snails
A living Lepus, or hare
A living Limnodromus griseus, or short-billed dowitcher
A living Lytechinus sea urchin
A living Lithobates pipiens (sometimes Rana pipiens), or northern leopard frog
Illustration of a living Lepomis sunfish
Fossilized skull of the Early Jurassic-Late Cretaceous bony fish Lepidotes
Shells in differing orientation of a Littorina sea snail, or periwinkle
A living Lasionycteris noctivagans, or silver-haired bat
A living Lasiurus borealis, or eastern red bat
Shell of a Lovenia sea urchin
A living Lymnaea (larger) freshwater snail, or Melantho snail
File:Leptorhynchos elegans.jpg
Fossilized foot bones of the Late Cretaceous oviraptorosaur Leptorhynchos
Fossilized shell of the Late Cretaceous ammonoid cephalopod Lewesiceras
Fossilized skull of the Late Cretaceous plesiosaur Libonectes
Restoration of the Late Cretaceous plesiosaur Libonectes with an anachronistic scuba diver to scale
Fossilized skeleton of the Late Triassic aetosaur Longosuchus
Restoration of the Late Triassic aetosaur Longosuchus
Fossil of the Cambrian arthropod Leanchoilia
Restoration in multiple views of the Cambrian arthropod Leanchoilia
A living Lagopus, or ptarmigan
Fossilized skeleton of the Eocene freshwater frigatebird Limnofregata
A living Lynx lynx, or Eurasian lynx
Illustrative skeletal reconstruction of the Late Cretaceous primitive horned dinosaur Leptoceratops
Restoration of the Late Cretaceous tyrannosaur Lythronax
Restoration of the Cambrian possible sea snail Latouchella
Living Lagopus muta, or rock ptarmigan
A living Larus hyperboreus, or glaucous gull
Shell of a Leptoxis freshwater snail
A living Lithobates sylvaticus (formerly Rana sylvaticus), or wood frog
Illustration of two modern species of Laccophilus water beetles
Divider
  • Fossilized skull of the Eocene-Oligocene three-toed horse Miohippus
Life restoration of the Carboniferous amphibian Megalocephalus
  • Life restoration of the Late Ordovician eurypterid ("sea scorpion") Megalograptus
  • Fossilized shell of the Devonian brachiopod Mucrospirifer
  • Fossilized shell of the Devonian brachiopod Mucrospirifer
  • Fossilized shell of the Devonian brachiopod Mucrospirifer
  • Diagram illustrating the known fossil material of two specimens of the Late Jurassic crocodile relative Macelognathus
  • Restoration of the Late Jurassic megalosaur Marshosaurus
  • Fossilized cranium of the Late Jurassic megalosaur Marshosaurus
  • Fossilized skull of the Late Cretaceous multituberculate mammal Meniscoessus
  • Fossilized skeleton of the Late Jurassic armored dinosaur Mymoorapelta
  • Fossilized skeleton of the Late Jurassic armored dinosaur Mymoorapelta
  • Fossilized skull of the Late Cretceous coelacanth fish Megalocoelacanthus
  • A heap of modern Modiolus, or horsemussels
  • Fossilized shell of a Modiolus, or horsemussel
  • Interior and exterior of a shell of a Macoma tellin
  • Restoration of a Mammut americanum, or American mastodon
  • Painting of a family of mammoths walking
    Restoration of a herd of Mammuthus columbi, or Columbian mammoths. The extent of the fur depicted is hypothetical. Charles R. Knight (1909).
  • A living Marginella margin sea snail
  • Fossilized skeleton of the Miocene-Pleistocene ground sloth Megalonyx
  • Shells in differing orientations of the parasitic sea snail Melanella
  • A living Melanerpes carolinus or red-bellied woodpecker
  • A living Melanopsis freshwater snail
  • A wild male Meleagris gallopavo, or turkey, displaying his facial coloration and tail feathers to attract a female
  • A living Mergus typical merganser
  • Multiple views of a fossilized shell of Mesalia tower sea snail
  • Living Mesophyllum red algae
  • A living Microtus pennsylvanicus, or meadow vole
  • Multiple views of a shell of a Mitromorpha sea snail
  • Two living Myliobatis eagle rays
  • Fossilized skeleton of the Pliocene-Holocene peccary Mylohyus
  • A living Myotis lucifugus, or little brown bat
  • Illustration (lower right, entry 15) of a fossilized shell in front and side views of the Silurian-Late Devonian brachiopod Meristella
  • Illustration in front and side views of a fossilized shell of the Silurian-Late Devonian brachiopod Meristella
  • Shell in multiple views of a Margarites sea snail
  • Fossilized shells of the Late Cretaceous ammonoid cephalopod Muramotoceras
  • Fossilized shell of the Jurassic-Cretaceous marine bivalve Myophorella
  • Fossilized shell of the Late Cretaceous marine bivalve Myophoria
  • Collection of living Mytilus mussels
  • Shells washed ashore of Mytilus mussels
  • A living Mytilus mussel clinging to a rock with its byssus threads
  • Shell in multiple views of a Mitra stictica, or pontifical mitre shell sea snail
  • Shell in multiple views of a Mitra tabanula mitre shell sea snail
  • Fossilized shell of the Carboniferous-Permian nautiloid cephalopod Metacoceras
  • Fossilized skull of the Late Triassic phytosaur Machaeroprosopus
  • Restoration of the Late Triassic phytosaur Machaeroprosopus
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Mammites
  • Living Membranipora bryozoan
  • Fossilized skeleton of the Late Triassic amphibian Metoposaurus
  • Restoration of the Late Triassic amphibian Metoposaurus with an anachronistic human to scale
  • Life restoration of the Late Triassic-Middle Jurassic synapsid (mammal precursor) Morganucodon
  • Fossilized skeleton of a Mammuthus columbi or Columbian mammoth
Fossilized shell of the Permian ammonoid cephalopod Metalegoceras
Assemblage of fossilized shells of the Late Cretaceous ammonoid cephalopod Menuites
Fossilized shell of the Late Cretaceous-Paleogene sea urchin Micraster
Restoration of the Pliocene-Pleistocene Miracinonyx, or American cheetah
Fossilized shell of the Middle Jurassic ammonoid cephalopod Macrocephalites
Fossilized shell of the Late Cretaceous ammonoid cephalopod Mantelliceras
Collection of Margarella sea snails
Fossilized shell of the Early-Late Cretaceous ammonoid cephalopod Mariella
A living Mediaster sea star
Fossilized shell of the Early Cretaceous ammonoid cephalopod Mortoniceras
Fossilized shell of the Early Cretaceous ammonoid cephalopod Mortoniceras
Fossilized cranium of the Miocene-Pleistocene saber-toothed cat Machairodus
Restoration of the Oligocene toothed-whale Macrodelphinus (background)
Living Madrepore coral
Foliage and berries of a Mahonia shrub
A living Makaira or marlin
Two views of a shell of a Malea ringens, or grinning tun
Diagram illustrating various Mammuthus species with a human to scale
Reconstructed skeleton of a Mammuthus exilis, or pygmy mammoth
A living Martes, or marten
A taxidermied Megachasma pelagios, or megamouth shark
Fossilized skull and limb bones of the Miocene horse Megahippus
A living Megaptera novaeangliae, or humpback whale
Restoration of the Eocene mammal Meniscotherium. Robert Bruce Horsfall (1913).
Restoration of the Miocene rhinoceros Menoceras
A living Mergus serrator, or red-breasted merganser
Illustration of a living Merluccius productus, or north Pacific hake
Restoration of the Miocene pronghorn Merriamoceros with an anachronistic human to scale
Restoration of the Miocene three-toed horse Merychippus
Fossilized skeleton of the Miocene pronghorn Merycodus
Skull fossils of the Oligocene-Miocene dog Mesocyon
Life restoration of the Eocene-Oligocene horse Mesohippus. Heinrich Harder (c. 1920).
Fossilized skeleton of the Miocene-Pleistocene manatee relative Metaxytherium
Restoration of the Paleocene-Eocene mammal Miacis
A living Microdipodops, or kangaroo mouse
A modern Microgadus, or tomcod
A living Microtus californicus, or California vole
Fossils of the Eocene-Oligocene three-toed horse Miohippus
Restoration of Miohippus (middle) and other Oligocene animals
Fossilized skull (top) and interpretive line drawing (middle) of the Miocene auk relative Miomancalla compared with the skull of a Holocene Pinguinus impennis, or great auk
A living Mirounga angustirostris, or northern elephant seal
A living Mitra idae, or Ida's miter sea snail
Shells of Alia carinata, or carinate dove shell sea snails
Exterior (left) and interior of the shell of a Modiolus capax, or fat horsemussel
Shell in multiple views of a Monoplex triton sea snail
Fossilized skeleton of the Miocene chalicothere mammal Moropus
A living Mustela frenata, or long-tailed weasel
Illustration of a living Myctophum lanternfish
Living Mytilus californianus, or california mussels
Shell of a Myurella augur sea snail
Fossilized skeleton of the Eocene mammal Macrocranion
Restoration of the Eocene mammal Macrocranion
A living Malus, or wild apple, in bloom
Life restoration of the Eocene brontothere mammal Megacerops
Restorative portrait, reconstructed skull, and actual fossil of the Miocene weasel relative Megalictis
A living Mellinus wasp with prey
A living Melospiza lincolnii, or Lincoln's sparrow
Restoration of the Eocene mammal Mesonyx
Restoration of the Eocene pangolin relative Metacheiromys
A living Microtus longicaudus, or long-tailed vole
A living Microtus ochrogaster, or prairie vole
Restoration of the Eocene opossum relative Mimoperadectes
Life restoration of the Eocene-Oligocene oreodont mammal Miniochoerus
Fossil of the Oligocene ant Miomyrmex
A living Mordella tumbling flower beetle
A living Mordellistena tumbling flower beetle
A living Mustela nigripes, or black-footed ferret
A pair of living Myrmica ants
Collection of Mercenaria mercenaria, also known as hard clams or quahogs
Shell of a Macoma tenta, or narrowed macoma clam
Shell of a Macrocallista maculata, or calico clam
A living Macrochelys temminckii, or alligator snapping turtle
A living Macrocypraea cervus, or Atlantic deer cowry
A living Magnolia virginiana, or sweetbay magnolia
Living Manicina stony coral
A living Margaretta flower
Shell of a Marsupina bufo, or chestnut frog shell sea snail
Shell of a Massyla nutmeg sea snail
Fossilized skeleton of the Pliocene-Pleistocene saber-toothed cat Megantereon
A living Melanerpes erythrocephalus, or red-headed woodpecker
Shell in multiple views of a Melongena melongena, or Caribbean crown conch
A living Melospiza georgiana, or swamp sparrow
Restoration of the Eocene-Oligocene oreodont mammal Merycoidodon. Heinrich Harder (1920).
A living Microhyla, or rice frog
Illustration of a living Micropterus, or black bass
A living Micrurus fulvius, or eastern coral snake
Living Millepora alcicornis, or sea ginger
A living Mimus polyglottos, or northern mockingbird
Shell of a Modiolus americanus
A living Modulus modulus, or tulip mussel
A living Molothrus ater, or brown-headed cowbird
Shell in multiple views of a Monoplex parthenopeus, or giant triton
A living Mormoops megalophylla, or ghost-faced bat
Shell of a Morum oniscus harp sea snail
A living Mugil mullet
Shell in multiple views of a Muricanthus murex sea snail
Shell of a Muricopsis murex sea snail
Living Mussa angulosa, or spiny flower coral
Living Mussismilia stony coral
Restoration of the Pleistocene-Holocene ground sloth Mylodon with an inset depicting its excrement and a skin fragment
A living Myotis grisescens, or gray bat
A living Myrica cerifera, or southern wax myrtle
A heap of modern Modiolus, or horsemussels
Fossilized shell of the Devonian-modern marine bivalve Modiolus, or horsemussel
Restoration of the Pliocene-Holocene ground sloth Megatherium. Robert Bruce Horsfall (1913).
A living Mephitis mephitis, or striped skunk
A living Microtus pinetorum, or woodland vole
Restoration of the mysterious Cambrian life-form Margaretia
Restorative model of the Pliocene-Pleistocene saber-toothed cat Megantereon
Fossilized skull of the Late Cretaceous plesiosaur Megacephalosaurus
Fossilized skull of the Late Cretaceous plesiosaur Megacephalosaurus
Restoration of a herd of the Eocene-Miocene oreodont mammal Merychyus
Living Myripristis soldierfishes
Fossilized skeleton of the Pliocene-Holocene elephant relative Mammuthus, or mammoth
Restoration of two of the Late Cretaceous Mosasaurus
Shell of the marine bivalve Mya truncata, also known as the blunt gaper or truncate softshell
A living Marmota monax, or groundhog
Shells of Modiolus modiolus, or northern horsemussels
Restorative model of the Cambrian velvet worm Microdictyon.
Fossilized plates of the Cambrian-Early Ordovician chiton Matthevia
Restoration of the Eocene-Miocene swamp rhinoceros Metamynodon. Charles R. Knight (1896).
Fossil of the Cambrian-Silurian trilobite Megistaspis
Restoration of the Late Cretaceous duck-billed dinosaur Maiasaura
Restoration of the Late Cretaceous horned dinosaur Medusaceratops
Restoration of the Late Cretaceous horned dinosaur Mercuriceratops
Life restoration of the Early Cretaceous oviraptorosaur Microvenator
Fossilized skeletons of the Late Cretaceous pterosaur Montanazhdarcho
Restoration of the Late Cretaceous primitive horned dinosaur Montanoceratops
Restoration of battling males of the Eocene brontothere mammal Megacerops
Fossilized skeleton of the Eocene-Miocene oreodont mammal Merychyus
Restorative portrait of the Oligocene-Miocene oreodont mammal Merycochoerus
Fossilized skeleton of the Miocene-Pleistocene saber-toothed cat Metailurus
Fossil of the Early Ordovician trilobite Megalaspides
Fossils of the Cretaceous theropod dinosaur egg oogenus Macroelongatoolithus
Fossils of the Cretaceous theropod dinosaur egg oogenus Macroelongatoolithus
Diagram illustrating the Middle Triassic ichthyosaur Mixosaurus with an anachronistic human to scale
Restoration of the Middle Triassic ichthyosaur Mixosaurus
Fossilized shell of the Middle Triassic ammonoid cephalopod Monophyllites
A living Myotis velifer, or cave myotis
Restoration of the Silurian eurypterid ("sea scorpion") Mixopterus
Fossil of the Silurian eurypterid ("sea scorpion") Mixopterus
A living Makaira nigricans, or Atlantic blue marlin
Living Marchantia liverworts
A living Metasequoia, or dawn redwood
A living Istiompax indica, or black marlin
A living Maretia heart urchin
Illustration of a living Melanogrammus aeglefinus, or haddock
A modern Merluccius albidus, or offshore hake
Illustration on a stamp of a living Mesoplodon, or mesoplodont whale
Illustration of a living Microgadus tomcod
A living Mobula
A living Monodon monoceros, or narwhal
A living Mycteroperca group
A living Myriophyllum, or watermilfoil
Fossilized cranium and interpretive illustration of the Permian primitive reptile Macroleter (B)
Life restoration of the Permian primitive reptile Macroleter
Restoration of the Permian primitive reptile Macroleter
Life restoration of the Permian amphibian Micraroter
Life restoration of the Permian synapsid (mammal precursor) Mycterosaurus
Restoration of the Permian synapsid (mammal precursor) Mycterosaurus
Fossilized skeleton of the Middle Triassic amphibian Mastodonsaurus
A living Mustela, or weasel
Shell in multiple views of a Meiocardia marine bivalve
Shell in multiple views of a Microdrillia sea snail
Restoration of the Late Triassic reptile Malerisaurus
Illustration of a shell of the freshwater snail Madagasikara
Fossil of the Late Cretaceous-Eocene sea urchin Micraster
Shell of a Monodonta top sea snail
Fossil of the Cambrian cyanobacterium Marpolia
Restoration of the Eocene tree Macginitiea with insets detailing its anatomy
Restorative portrait of the Eocene saber-toothed creodont mammal Machaeroides
Shell in multiple views of a llving Microphysula land snail
Fossilized skeleton of the Eocene perch relative Mioplosus
Fossilized jaw of the Late Jurassic crocodilian relative Macelognathus
Shell of a Mactra marine bivalve, also known as trough shells or duck clams
Fossil of the Late Jurassic-Early Cretaceous crustaceans Mecochirus
Restoration of the Late Jurassic plesiosaur Megalneusaurus
Life restoration of the Late Cretaceous horned dinosaur Machairoceratops
Fossilized skeletons of the Early Cretaceous long-necked dinosaur Moabosaurus
Fossil of the Cambrian trilobite Mesonacis
Restoration of the Silurian trilobite Miraspis
A living Morus bassanus, or northern gannet
Illustration of a living Moxostoma sucker
A living Mustela nivalis, or least weasel
Divider
  • Fossil of the Cambrian trilobite Nevadia
  • Shell of a Nucella lamellosa murex snail
  • Fossilized shell of the Early Devonian – Triassic sea snail Naticopsis
  • Fossilized shell of the Carboniferous-Permian brachiopod Neospirifer
  • Fronds of the Carboniferous seed fern Neuropteris
  • Exterior of the shell of a modern specimen of the Early Ordovician-modern marine bivalve Nucula
  • Interior of a fossilized shell of the Early Ordovician-modern marine bivalve Nucula
  • Restoration of several species of the Late Cretaceous ammonoid cephalopod Nostoceras
  • Known material diagram and fossils of the skull found in Alaska of the Late Cretaceous tyrannosaur Nanuqsaurus
  • Restoration of the Late Cretaceous tyrannosaur Nanuqsaurus
Illustration of a fossil of the head of the Cambrian trilobite Nephrolenellus
Fossil of the Cambrian trilobite Nevadella
Life restoration of the Late Triassic thalattosaurs Nectosaurus (right) and Thalattosaurus
Known material diagram of the skull of the Late Triassic thalattosaur Nectosaurus
Opalized guard of the belemnoid cephalopod Neohibolites
Shell of a Narona clavatula nutmeg sea snail
A living Nassarius fossatus, or channeled basket snail
Fossilized skeleton of the Pleistocene Odocoileus lucasi, or American mountain deer
Fossilized skeleton of the Pleistocene Old World vulture Neogyps
Fossilized skeleton of the Miocene aquatic mammal Neoparadoxia
Fossilized skeleton of the Miocene Neophrontops
A living Nicrophorus marginatus burying beetle
Fossilized partial cranium of the Miocene saber-toothed cat Nimravides
Fossilized skull of the Oligocene false saber-toothed cat Nimravus
Fossilized skeleton of the Pleistocene ground sloth Nothrotheriops
Shell of Notoacmea limpet
A living Notorynchus cepedianus, or broadnose sevengill shark
A living Numenius phaeopus, or whimbrel
A living Nephila, or golden silk orb-weaver
Fossilized skeleton of the Eocene primate Notharctus
Fossilized skull of the Eocene primate Notharctus
A living Notonecta, or common backswimmer
A living Numenius madagascariensis, or far eastern curlew
A living young Bubo scandiacus (formerly Nyctea scandiaca), or snowy owl
Flower of a living Nymphaea
A living Nysius false chinch bug
Illustration of a living Notorynchus cow shark
Shell in multiple views of a Nannodiella sea snail
Shell of a Nassarina dove sea snail
Shells in differing orientations of a Phrontis antillara (formerly Nassarius antillarum), or the Antilles nassa sea snail
Shells of Phrontis vibex (formerly Nassa vibex), or bruised nassa sea snails
A living Nasua, or coati
Shell in multiple views of a Naticarius canrena moon sea snail
A living Nerodia cyclopion, or green water snake
A living Necturus, or mudpuppy
Illustration of the recently extinct Neomonachus tropicalis, or Caribbean monk seal
A living Nerodia fasciata, or banded water snake
Preserved Neverita moon sea snail
Shell of a Niveria suffusa false cowrie
Shells of a Nodipecten nodosus, or lion's paw scallop
A living Notophthalmus viridescens, or eastern newt
A living Numenius americanus, or long-billed curlew
Exterior and interior of a Nummulite viewed from above
A living Nyctanassa violacea, or yellow-crowned night heron
Shell in multiple views of a Nerita polita sea snail
A living Negaprion brevirostris, or lemon shark
Fossilized shell of the Middle Jurassic ammonoid cephalopod Normannites
Fossilized frond of the Carboniferous seed fern Neuropteris
Illustrations of fossilized foliage of the Carboniferous-Permian plant Noeggerathia
Restoration of the Late Cretaceous pterosaur Nyctosaurus
Living Nassella, or needlegrass
A living Notropis, or eastern shiner
Shell of a Niso sea snail
Shell in multiple views of a Neptunea despecta whelk sea snail
A living Neovison vison, or American mink
A living Napaeozapus insignis, or woodland jumping mouse
A living Neofiber, or round-tailed muskrat
A living Nerodia sipedon, or northern water snake
Illustration of a Navicula diatom alga
Fossilized skeleton of the Late Cretaceous-Eocene bony fish Notogoneus
A living Nelumbo lotus
A living Nuphar water lily
A living Nerodia rhombifer, or diamondback water snake
Fossil of the Cambrian trilobite Nephrolenellus
Fossilized head of the Cambrian trilobite Nephrolenellus
Fossil of the Cambrian trilobite Nevadia
Fossilized shell of the Triassic bivalve Neomegalodon
Fossilized foliage of the Triassic-Middle Jurassic horsetail relative Neocalamites
Fossilized shell of the Late Cretaceous-Quaternary oyster Nicaisolopha
Restoration of the Late Cretaceous therizinosaur Nothronychus
A living Neotoma micropus, or southern Plains woodrat
A living Nitzschia diatom
Illustration of a living Numenius borealis, or Eskimo curlew. Archibald Thorburn.
Anatomy of a de-shelled Nototeredo shipworm
A living Nautilus
Shell of a Nodipecten marine scallop
A living Nelumbo lotus
A living Nectandra tree, or sweetwood
A living Neotamias cinereicollis, or gray-collared chipmunk
A living Notophthalmus, or North American newt
Restoration of the Cambrian-Silurian arthropod Naraoia
Fossilized skeleton of the Late Cretaceous-Eocene beaked salmon relative Notogoneus
A living Nucifraga columbiana, or Clark's nutcracker
A taxidermied Numenius borealis, or Eskimo curlew
Fossilized jaw and ilium of the Late Jurassic herbivorous dinosaur Nanosaurus
Fossilized skull of the Late Cretaceous tyrannosaur Nanotyrannus, possibly a juvenile Tyrannosaurus rather than a distinct genus
Known material diagram of the Late Cretaceous horned dinosaur Nasutoceratops
Fossilized skeleton of the Late Cretaceous Nothronychus
Fossilized skeleton of the Eocene primate Notharctus tenebrosus
A living Nocomis raneyi, or bull chub
Divider
  • Fossilized valves of the Permian-modern oyster Ostrea
  • Fossilized shell in multiple views of the Middle Jurassic ammonoid cephalopod Oxycerites
  • Restoration of the Cambrian trilobite Olenellus
  • Restoration of the Carboniferous-Permian amphibian Ophiderpeton
  • Restoration of the Carboniferous-Permian cartilaginous fish Orodus
  • Restoration of the Carboniferous-Permian freshwater shark Orthacanthus
  • Restoration of the Late Triassic–Early Jurassic synapsid (mammal precursor) Oligokyphus
Illustration of fossils of the Cambrian brachiopod Obolella
Fossil of the Cambrian trilobite Olenellus
Illustration of a fossil of the Cambrian trilobite Olenellus
Fossil of the Cambrian trilobite Olenellus
Restoration of the Early Triassic ammonoid cephalopod Owenites
A living Oceanodroma furcata, or fork-tailed storm petrel
Shell of an Ocenebra murex sea snail
Shell of an Odostomia donilla pyram shell sea snail
Shell of an Oenopota tabulata sea snail
Three living Olivella biplicata, or purple dwarf olive sea snail
Restoration of a school of the Miocene-Pleistocene Oncorhynchus rastrosus, or saber-toothed salmon
Illustration of a living Oneirodes dreamer with a close-up of its lure (upper right)
A living Oreamnos americanus, or mountain goat
Restoration of the Miocene pseudo-toothed bird Osteodontornis
A living Oxyura jamaicensis, or ruddy duck
A living Ochotona princeps, or American pika
A living Odynerus potter wasp
Illustration of a living Oligomerus death-watch beetle
A living oligotrich ciliate
A living Ophisaurus, or glass lizard
A living Hydrotaea house fly
A living Orchelimum katydid
A living Oreamnos harringtoni, or Harrington's mountain goat
Fossilized skeleton of the Eocene horse Orohippus
A living Orontium, or golden-club
Flowers and foliage of a living Osmanthus
Restoration of the Paleocene-Eocene creodont mammal Oxyaena
A living Oxycera soldier fly
Fossil from Dinosaur State Park and Arboretum of the Late Triassic-Middle Jurassic sauropodomorph dinosaur footprint ichnogenus Otozoum
Shell of a Odostomia laevigata, or ovoid odostome sea snail
Shell of a Oliva reticularis, or netted olive sea snail
Shell in multiple views of a Oliva sayana, or lettered olive sea snail
Interior and exterior of the shell of an Onustus carrier shell sea snail
Fossil of the Permian-modern crustacean burrow ichnogenus Ophiomorpha
A living Ophisaurus compressus, or Island glass lizard
A living Opsanus toadfish
Living Orbicella annularis, or boulder star coral
A living Oryzomys palustris, or marsh rice rat
At the top of the picture is a line representing twenty meters. Below this is a gray megalodon silhouette that measures twenty meters, below is a red megalodon silhouette that measures fifteen meters, below is a violet whale shark silhouette that measures ten meters, below is a green great white shark that measures five meters. Standing next to this shark is a black human silhouette that stands two meters.
Diagram illustrating the largest (grey) and most conservative (red) size estimates of the Miocene-Pliocene shark Carcharocles megalodon (sometimes Carcharodon or Otodus megalodon) with a whale shark (violet), great white shark (green), and anachronistic human (black) to scale
Restoration of a pair of the Oligocene-Miocene camel Oxydactylus. Robert Bruce Horsfall (1913).
Fossil of the Cambrian trilobite Ogygopsis
Assemblage of fossils of the Cambrian trilobite Ogygopsis
Fossilized skeleton of the Oligocene-Miocene camel Oxydactylus
Fossil of the Carboniferous crinoid ("sea lily") Onychocrinus
Close-up of a fossilized skeleton of the Carboniferous-Permian cartilaginous fish Orodus
Life restoration of the Middle-Late Devonian lobe-finned fish Onychodus
Illustration of a fossilized lower jaw and teeth of the Middle-Late Devonian lobe-finned fish Onychodus
Fossilized tooth whorl of the Middle-Late Devonian lobe-finned fish Onychodus
Fossilized skeleton of the Carboniferous-Permian freshwater shark Orthacanthus
A living Ortalis, or chachalaca
Flower, buds, and foliage of a living Operculina
A living Ostracion boxfish
Life restoration of the Miocene sperm whale Orycterocetus
Fossil of the Cambrian trilobite Orygmaspis
Fossilized tooth of the Late Cretaceous giant sawfish Onchopristis
Fossil of the Ordovician trilobite Ogygites
Fossil of the Ordovician trilobite Ogyginus
Fossilized partial cranium of the Late Cretaceous armored dinosaur Oohkotokia
Restoration of the Late Cretaceous herbivorous dinosaur Orodromeus
Life restoration of the Late Cretaceous herbivorous dinosaur Oryctodromeus in a burrow
Living Onoclea ferns
Shell in multiple views of an Oreohelix land snail
Portrait of a living Ophisaurus ventralis, or eastern glass lizard
Illustration of a fossil of the Cambrian trilobite Olenellus
Fossil preserving carbon films left by the legs and antennae of the Cambrian trilobite Olenoides
Restoration of the Cambrian priapulid worm relative Ottoia
Fossil of the Cambrian priapulid worm relative Ottoia
Fossilized teeth of the Cambrian priapulid worm relative Ottoia
Life restoration of the Middle-Late Triassic ichthyosaur Omphalosaurus
Fossil of the Permian-modern crustacean burrow ichnogenus Ophiomorpha
Life restoration of the Permian synapsid (mammal precursor) Oedaleops
Life restoration of the Permian amphibian Onchiodon
Fossilized skeleton of the Permian amphibian Onchiodon
Fossilized skeleton of the Carboniferous-Permian synapsid (mammal precursor) Ophiacodon
Restoration of the Late Cretaceous horned dinosaur Ojoceratops
Known material diagram of the Late Cretaceous oviraptorosaur Ojoraptorsaurus
Restoration of the Late Cretaceous ostrich dinosaur Ornithomimus
Restoration of the Miocene pronghorn Osbornoceros
Fossil of the Silurian-Devonian trilobite Odontochile
Fossil of the Silurian-Devonian trilobite Odontochile
Illustration of a fossil of the Cambrian trilobite Olenellus
Fossil teeth of Odontaspis winkleri from Khouribga (Morocco), 55-45 mya
A living Odontaspis ferox, or smalltooth sand tiger
A living Opsanus tau, or oyster toadfish
Living Osmunda regalis, or royal ferns
Restoration of the Carboniferous-Permian synapsid (mammal precursor) Ophiacodon
Fossilized skeleton of the Carboniferous-Permian synapsid (mammal precursor) Ophiacodon
Fossilized tooth of the Carboniferous-Permian freshwater shark Orthacanthus
A living Ochotona, or pika
A living Ocotea tree
Shell of an Odostomia fusulus pyram sea snail
A living Onychomys torridus, or southern grasshopper mouse
Fossilized vertebrae of the Cretaceous sawfish Onchosaurus
Partial fossilized skeleton of the Late Jurassic bony fish Ophiopsis
Fossilized shell of the Late Cretaceous ammonoid cephalopod Ostlingoceras
Restoration of the Eocene bat Onychonycteris
A living Oreamnos, or mountain goat
Fossilized skeleton of the Late Jurassic theropod dinosaur Ornitholestes
Restoration of the Late Jurassic ichthyosaur Ophthalmosaurus
Fossilized skeleton of the Late Jurassic herbivorous dinosaur Othnielosaurus
Fossil of the Permian-Late Cretaceous fern Osmundites
Illustration of a fossilized partial skull of the Paleocene-Eocene pseudo-toothed bird Odontopteryx
A living Ovis dalli, or Dall sheep
Divider
  • Foliage (left) and fruit (right) of a living Persea tree
  • Several living Picea, or spruce trees
  • Montage of photographs in spring (top left), summer (top right), autumn (bottom left), and winter (bottom right) of Populus, or poplar tree
Fossilized skeleton of the Eocene perch Priscacara
  • A living Puma
  • Fossils of the Late Devonian-Permian fern-like fronds Pecopteris
  • Fossilized shell of the Silurian-Middle Devonian brachiopod Pentamerus
  • Life restoration of the Carboniferous-Permian amphibian Phlegethontia.
  • Historical skeletal reconstruction of the Carboniferous-Permian amphibian Phlegethontia. Fritsch (1910).
  • Restoration of the Carboniferous-Permian amphibian Phlegethontia.
  • Fossilized shell of the Ordovician brachiopod Plaesiomys
  • Fossilized shells of the Silurian-Early Triassic sea snail Platyceras
  • Fossilized skeleton of the Carboniferous amphibian Platyrhinops
  • Fossilized shell of the Middle Ordovician-Silurian brachiopod Platystrophia
  • Fossil of the Silurian-Carboniferous tabulate coral Pleurodictyum
  • Various conodont elements, including those of Polygnathus (specimens 8, 10, and 11)
  • Various conodont elements of Polygnathus
  • Internal structure of the Silurian-Late Devonian tree-like probable fungus Prototaxites
"Schunnemunk tree" specimen of the Silurian-Late Devonian tree-like probable fungus Prototaxites
Thin section under a light microscope showing the internal structure of the Silurian-Late Devonian tree-like probable fungus Prototaxites
Restoration with a conifer-like body plan of the Silurian-Late Devonian tree-like probable fungus Prototaxites. John William Dawson (1888).
  • Restoration based on the "Schunnemunk tree" fossil of the Silurian-Late Devonian tree-like probable fungus Prototaxites
  • Fossil of the Silurian-Middle Devonian eurypterid ("sea scorpion") Pterygotus
  • Restoration of the underside of the Silurian-Middle Devonian eurypterid ("sea scorpion") Pterygotus
  • Restoration of the Silurian-Middle Devonian eurypterid ("sea scorpion") Pterygotus
  • Assemblage of the Early-Middle Devonian brachiopod Paraspirifer
  • Fossilized tooth of the Carboniferous-Permian shark Petalodus
  • Fossilized shell of the Silurian-Early Triassic sea snail Platyceras
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Pachydiscus
  • Fossilized theca of the Carboniferous blastoid echinoderm ("sea bud") Pentremites
  • Three fossilized calyces of the Devonian-Permian crinoid ("sea lily") Platycrinites
  • Fossilized skeletons of the Late Cretaceous bony fish Pachyrhizodus
  • Fossilized skeleton of the Late Cretaceous mosasaur Platecarpus
  • Restoration of the Late Cretaceous mosasaur Platecarpus
  • Restoration of the Late Cretaceous polycotylid plesiosaur Polycotylus giving birth
  • Close-up view of a fossilized skull and skeletal remains of the Late Cretaceous mosasaur Prognathodon
  • Life restoration of the Late Cretaceous mosasaur Prognathodon
  • Life restorations of two species of the Late Cretaceous bony fish Protosphyraena; P. perniciosa (top) and P. nitida (bottom)
  • Fossilized snout of the Late Cretaceous bony fish Protosphyraena
  • Fossilized dentary, splenial, and pectoral fin spine of the Late Cretaceous bony fish Protosphyraena
  • Fossilized skeleton of the Late Cretaceous sea turtle Protostega
  • Fossilized teeth of the Cretaceous shark Pseudocorax
  • Fossil of the Cambrian trilobite Pagetia
  • Fossil of the Cambrian trilobite Paradoxides
  • Damaged fossil lacking the free cheeks of the Cambrian trilobite Paradoxides
  • Fossil of the Cambrian trilobite Pagetia. This specimen was described by Linnaeus, the founder of modern biological nomenclature
  • Assemblage of fossils of the Cambrian trilobite Itagnostus interstrictus, until recently known as Peronopsis interstricta
  • Fossil of the Cambrian trilobite Phalagnostus
  • Fossil of the Early Ordovician graptolite Phyllograptus
  • Shell and byssus of a modern specimen of the marine bivalve Pinna
  • Fossil of the Silurian-Devonian horn coral Pseudoamplexus
  • Fossilized shell of a Pseudomelania sea snail
  • Fossil of the primitive Devonian vascular plant Psilophyton
  • Pearls and shell interior of a Pteria, or winged oyster
  • Interiors and exteriors of multiple shells of Pteria, or winged oysters
  • Interior and exterior of a shell of a Pteria, or winged oyster
  • Fossil of the Cambrian trilobite Ptychagnostus
  • Fossilized skeleton found in Alaska of the Late Cretaceous horned dinosaur Pachyrhinosaurus
  • Restoration of two of the Late Cretaceous horned dinosaur Pachyrhinosaurus perotorum
  • Fossilized partial skull and holotype specimen in multiple views of the Late Cretaceous horned dinosaur Pachyrhinosaurus perotorum
  • Restored and illustrated skull changes over development of the Late Cretaceous horned dinosaur Pachyrhinosaurus
  • Fossilized foliage of the Carboniferous-Late Cretaceous plant Pagiophyllum
  • Shells of Pecten scallops
  • Fossilized shells of the Cretaceous-modern scallop Pecten
  • Fossilized shell of the Cretaceous brachiopod Peregrinella
  • Fossilized shell of the Early Triassic-Pliocene marine bivalve Pholadomya
  • Restoration of the Early Jurassic-Late Cretaceous ammonoid cephalopod Phylloceras
  • Fossilized shell of the Early-Late Cretaceous ammonoid cephalopod Phyllopachyceras
  • Fossils of the burrow ichnogenus Planolites
  • Leaves and fruit of a living Platanus, or plane tree
  • Trunk and roots of a living Platanus, or plane tree
  • Fossilized shell of the Carboniferous-Triassic nautiloid cephalopod Pleuronautilus
  • Fossilized shell of the Triassic ammonoid cephalopod Protrachyceras
  • Fossilized shell of the Early-Late Cretaceous ammonoid cephalopod Puzosia
  • Life restoration of the Late Triassic phytosaur Parasuchus
  • Fossilized skeleton of the Late Triassic aetosaur Paratypothorax
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Placenticeras
  • Fossilized skeleton of the Late Triassic synapsid (mammal precursor) Placerias
  • Restoration of the Late Triassic synapsid (mammal precursor) Placerias with an anachronistic human to scale
  • Diagram illustrating the Late Triassic crocodile relative Poposaurus with an anachronistic human to scale
  • Restoration of the Late Triassic crocodile relative Poposaurus with an anachronistic human to scale
  • Fossilized skeleton of the Late Triassic crocodile relative Postosuchus
  • Restoration of the Late Triassic crocodile relative Postosuchus with an anachronistic human to scale
  • Restoration of the Early Jurassic frog Prosalirus
  • Restoration of the Late Triassic phytosaur Protome
  • Fossilized skeleton of the Early Jurassic crocodile relative Protosuchus
  • Restoration of the Early Jurassic crocodile relative Protosuchus
A living Procyon lotor, or raccoon
Restoration of the Cambrian trilobite Peachella
Fossil of the mysterious Ediacaran animal Pteridinium
Fossilized shell of the Early-Late Cretaceous ammonoid cephalopod Pachydesmoceras
Fossilized shell of the Late Cretaceous ammonoid cephalopod Parapuzosia with a human indicating its size
Fossilized shell of the Late Cretaceous ammonoid cephalopod Peroniceras
Restoration of the Late Cretaceous mosasaur Plesiotylosaurus with an anachronistic scuba diver to scale
Fossilized skeleton of the Late Cretaceous mosasaur Plotosaurus
Restoration of the Late Cretaceous mosasaur Plotosaurus
Restoration of the Late Cretaceous mosasaur Plotosaurus
Shell in multiple views of a Polinices moon sea snail
Fossilized shell of the Paleocene-modern moon snail Polinices
Fossilized shell of the Late Cretaceous ammonoid cephalopod Polyptychoceras
Fossilized shell of the Late Cretaceous ammonoid cephalopod Polyptychoceras
Shells of Potamides horn sea snails
Fossilized partial skull of the Late Cretaceous mosasaur Prognathodon
A close-up view of the teeth of the Late Cretaceous mosasaur Prognathodon
Microscopic views of the fibrous tissues and microstructures recovered from a humerus of the Late Cretaceous mosasaur Prognathodon
Skull of Prognathodon solvayi, the type species of the genus.
Fossilized skull of the Late Cretaceous mosasaur Prognathodon
A side-by-side comparison of a typical "crushing" mosasaur tooth (left, Igdamanosaurus) and a typical "cutting" mosasaur tooth (right, Mosasaurus). Teeth of Prognathodon seem to contain characteristics of both.
Life restoration of the Late Cretaceous mosasaur Prognathodon preying upon an ammonoid cephalopod
Restoration of the Late Cretaceous mosasaur Prognathodon
Fossilized shell of the Early Cretaceous ammonoid cephalopod Pseudothurmannia
Fossilized shell of the Jurassic-Cretaceous marine bivalve Pterotrigonia
Fossilized skeleton of the Paleoparadoxia
Restoration of the Miocene aquatic mammal Paleoparadoxia
Fossilized skull of the Miocene horse Parahippus
A modern Paralichthys large-toothed flounders
Restoration of the Miocene-Pliocene dolphin Parapontoporia (top)
Fossilized skull of the Miocene-Pliocene dolphin Parapontoporia (left)
Restoration of the Miocene baleen whale Parietobalaena and calf
Close-up portrait of a living Parribacus slipper lobster
Shell of a Patelloida limpet
Reconstruction of a fossilized skull of the Oligocene-Pleistocene pseudo-toothed bird Pelagornis, with close-up insets of its pseudo-teeth
A living Pelecanus occidentalis, or brown pelican
Fossilized skull of the Eocene-Oligocene lizard Peltosaurus
Interior of the shell of a Periglypta venus clam
A living Perognathus pocket mouse
A living Peromyscus truei, or pinyon mouse
Fossilized shell of the Oligocene-modern conch sea snail Persististrombus
Shells of Petricola venus clams
A living Phalacrocorax auritus, or double-crested cormorant
A living Phalaropus lobatus, or red-necked phalarope
Illustration of a fossilized cranium of the Oligocene-Miocene bone-crushing dog Phlaocyon
Illustration of a fossilized mandible of the Oligocene-Miocene bone-crushing dog Phlaocyon
A living Phoebastria albatrus, or short-tailed albatross
Two Phoenicopterus, or flamingos
A living Phrynosoma, or horned lizard
Shell of a Phyllonotus murex sea snail
Foliage and cones of a Pinus muricata, or bishop pine
A living Piranga ludoviciana, or western tanager
A living Pitymys vole
A living Plegadis chihi, or white-faced ibis
Restoration of the Paleocene-Eocene primate Plesiadapis
A highly camouflaged Pleuronichthys righteye flounder
Fossilized skull of the Miocene horse Pliohippus
Restoration of the Miocene walrus Pliopedia
Fossilized partial skull of the Miocene dog-like bear relative Plithocyon
A living Pluvialis squatarola, or grey plover
Living Pocillopora, or cauliflower coral
Illustration of a fossilized skull of the Oligocene false faber-toothed cat Pogonodon
Exterior of the shell of a Polymesoda basket clam
A modern Porichthys notatus, or plainfin midshipman
Living Porites stony coral
A living Prionace glauca, or blue shark
Illustration of a living Pristiophorus sawshark
Fossilized tooth of the Eocene brontothere mammal Protitanops
Restoration of the Eocene brontothere mammal Protitanops
Protylopus petersoni skull
Illustration of a fossilized skull of the Eocene camel Protylopus
Close-up view of a fossilized shell of the Oligocene-Pliocene sea turtle Psephophorus
Hypothetical restoration of the Oligocene-Pliocene sea turtle Psephophorus
Fossilized mandible of the Miocene cat Pseudaelurus
Fossilized shell of the Eocene-modern jewelbox marine bivalve Pseudochama
A living Pseudomelatoma sea snail
Living Pseudotsuga, or Douglas firs
A living Gymnura, or butterfly ray
Shell in multiple views of a Pteropurpura festiva, or festive murex sea snail
Illustration of a fossilized skull of the Paleocene multituberculate mammal Ptilodus
A living Sooty shearwater (formerly Puffinus griseus), or sooty shearwater
A living Ardenna tenuirostris (formerly Puffinus tenuirostris), or short-tailed shearwater
Shell of a Pusula false cowrie sea snail
Shell of a Pyramidella adamsi, or Adams' pyram shell sea snail
Restoration of the Carboniferous-Permian sail-backed amphibian Platyhystrix
Life restoration of the Carboniferous-Permian sail-backed amphibian Platyhystrix (small, foreground) and the likewise sail-backed synapsid (mammal precursor) Edaphosaurus
Fossilized mandibles of the Paleocene-Eocene mesonychian mammal Pachyaena
A living Paederus rove beetle
Illustration of a fossilized cranium of the Eocene-Miocene carnivoran mammal Palaeogale
Fossilized skull of the Oligocene rabbit relative Palaeolagus
Fossilized partial skull of the Paleocene-Eocene creodont mammal Palaeonictis
Fossilized skeleton of the Eocene mammal Palaeosinopa
Fossilized skeleton of the Eocene brontothere mammal Palaeosyops
Restorative model and fossilized skull of the Eocene brontothere mammal Palaeosyops
Fossil of the Eocene wasp Palaeovespa
Foliage and berries of a living Panax
A living Panorpa scorpionfly
A living Parandra longhorn beetles
Fossilized partial skull and limb bone of the Eocene-Oligocene camel Paratylopus
Restoration the Eocene-Oligocene camel Paratylopus (upper right)
Fruit of a living Parthenocissus
Illustration of a living Passaloecus wasp
Fossilized skeleton of the Eocene creodont mammal Patriofelis
Restoration of the Eocene creodont mammal Patriofelis. Charles R. Knight (1896).
A living Penthetria march fly
A living Pepsis spider wasp
Fossilized mandible of the Eocene-Miocene mammal Peratherium
Modern fruit of Persea americana, or avocados
Fossil of the Oligocene ant Petraeomyrmex
A living Phalacrocorax, or cormorant
Restoration of the Paleocene-Eocene ungulate Phenacodus. Charles R. Knight (1898).
Flowers of a living Philadelphus, or mock-orange
A living Philanthus, or beewolf
A living Phrynosoma douglasii, or pygmy short-horned lizard
A living Phyllobius weevil
A living Phyllophaga New World scarab
A living Phymatodes longhorn beetle
A living Pica hudsonia, or black-billed magpie
A living Pimpla wasp
A living Platycheirus hoverfly
A pair of living Plecia march flies
Fossilized skeleton of the Paleocene-Eocene primate relative Plesiadapis
A living Podiceps grebe
Fossilized skeleton of the Eocene-Oligocene camel Poebrotherium
Life restoration of the Eocene-Oligocene camel Poebrotherium
A preserved Pogonomyrmex harvester ant
A living Porzana carolina, or sora
Living Potamogeton pondweed
Illustration of a fossil of the Eocene butterfly Prodryas
Fossil of the Eocene ant Proiridomyrmex
A living Prosopis tree
Fossil of the Oligocene ant Protazteca
Fossilized skeleton of the Eocene horse Protorohippus
Protorohippus
Fossilized mandible of the Late Cretaceous-Paleocene mammal Protungulatum
Illustration of a branch, fruits, and flowers of a living Prunus gracilis, or Oklahoma plum
A living Pseudacris, or chorus frog
A living Pseudacris triseriata, or western chorus frog
Replica of a fossilized cranium of the Miocene horse Pseudhipparion
Preserved Pseudomyrmex ant
Fossilized skeleton of the Eocene protoceratid mammal Pseudoprotoceras
Restoration of the Paleocene taeniodont mammal Psittacotherium
Fruits of a living Ptelea, or hoptree
A living Pterostichus ground beetle
Fossilized skeleton of the Paleocene multituberculate mammal Ptilodus
A living Ptosima jewel beetle
Restoration of the Late Cretaceous pterosaur Pteranodon
A living Pandion haliaetus, or osprey
Shell of a Parametaria dove sea snail
Fossilized teeth of the Eocene-Pleistocene shark Parotodus, or the false-toothed mako
Shell of a Parviturbo
A living Passerculus sandwichensis, or savannah sparrow
A living Passerella iliaca, or fox sparrow
Close-up portrait of a Passerina, or North American bunting
A living Pecari
A living Pelecanus erythrorhynchos, or American white pelican
Shell in multiple views of a Peristernia tulip sea snail
The appearance of a Podomys floridanus, or Florida mouse, is similar to the Peromyscus shown in this illustration
Shell of a Persicula sea snail
Shell in multiple views of a Petaloconchus worm shell sea snail
A living Petrolisthes porcelain crab
A living Phoenicopterus ruber, or American flamingo
Shell in multiple views of a Phyllonotus pomum, or apple murex sea snail
Shells in differing orientations of Physa freshwater bladder snails
Living Pinus taeda, or loblolly pines
Fossilized skull of the Miocene baleen whale Piscobalaena
Shell in multiple views of a Planorbella duryi, or the Seminole rams-horn freshwater snail
Fossilized skeleton of the Miocene elephant relative Platybelodon
A living Plegadis ibis
Shell in multiple views of a Pleuroploca sea snail
A living Podiceps auritus, or horned grebe
A living Poecilia latipinna, or sailfin molly
Shell in multiple views of a Polinices lacteus, or milk moon sea snai
Shells in differing orientations of Polinices hepaticus moon sea snails
Shell in multiple views of a Polygyra septemvolva land snail
Shells in differing orientations of Polystira albida, or white giant turris sea snails
Illustration of a living Pomacea paludosa, or freshwater Florida applesnail
Living Porites porites, also known as hump or finger coral
Living Porites astreoides, or mustard hill coral
A living Porphyrio martinicus, or American purple gallinule
Restoration of the Miocene deer relative Procranioceras
Shell in multiple views of a Prunum guttatum margin sea snail
A living Psammechinus sea urchin
A living Pseudacris ornata, or ornate chorus frog
A living Pseudemys nelsoni, or Florida red-bellied cooter
A living Pseudobranchus, or dwarf siren
Living Pseudodiploria stony coral
Shell of a Psilaxis staircase shell sea snail
Shell of a Pterynotus alatus murex sea snail
A living Puffinus puffinus, or Manx shearwater
Fossilized shell in multiple views of a Pusula pediculus
Pyrazus
Shell in multiple views of a Pyrgospira tampaensis, or the Tampa turrid sea snail
Fossil of the Late Ordovician-Late Devonian trilobite Phacops
A living Peromyscus leucopus, or white-footed mouse
A living Physeter macrocephalus, or sperm whale
A living Placopecten magellanicus, or Atlantic deep-sea scallop
A living Pogonias cromis, or black drum
A living Pseudotriton ruber, or red salamander
A living Phoebe
Illustration of a fossilized shell in multiple views of the Paleozoic mollusc Pelagiella.
Illustration of a fossilized shell of the Paleozoic mollusc Pelagiella.
Fossil of the Middle Ordovician trilobite Pliomera
Pearls and interior of the shell of a Pteria, or winged oyster
Interiors and exteriors of multiple shells of Pteria, or winged oysters
Interior and exterior of the shell of a Pteria, or winged oyster
A living Pinus, or pine tree
Foliage of a living Pseudolarix, or golden larch tree
Fossil of the Silurian-Carboniferous crinoid ("sea lily") Periechocrinus
Fossil in an enrolled posture of the Late Ordovician-Late Devonian trilobite Phacops
Fossilized skeleton of the Carboniferous-Permian bony fish Platysomus
Restoration of the Carboniferous-Permian bony fish Platysomus
Fossilized skeleton of the Carboniferous-Permian bony fish Platysomus
Restoration of the Carboniferous Chimaera relative Polysentor
Fossil of the Carboniferous insect Protophasma
Restoration of the Carboniferous insects Protophasma and Titanophasma
Fossilized skeleton of the Carboniferous snake-like amphibian Pseudophlegethontia
Fossilized shell of the Early-Middle Devonian brachiopod Paraspirifer
Light micrograph of a Pinnularia alga
Light micrograph of a Pinnularia alga
Assemblage of fossils of the Late Devonian plant Protosalvinia
Light micrograph of a fossil of the Late Devonian plant Protosalvinia
Cross-section through a fossilized stem of the Devonian-Permian tree fern Psaronius
Restoration of the Devonian-Permian tree fern Psaronius. Auguste Faguet (1877).
Vascular anatomy of a stem of the Devonian-Permian tree fern Psaronius
Fossil of the Carboniferous crustacean Peachocaris
Fossil of the Late Ordovician cystoid echinoderm Pleurocystites
Restoration of the Late Devonian placoderm fish Ptyctodus
Fossilized skeleton of the Permian bony fish Palaeoniscum
Restoration of the Carboniferous reptile Petrolacosaurus
Fossilized skeleton of the Late Cretaceous sea turtle Protostega
A living Perca flavescens, or yellow perch
A living Phrynosoma cornutum, or Texas horned lizard
A living Pomoxis, or crappie
Petrified trunk segment of the Late Cretaceous-Miocene palm wood Palmoxylon
Upper branches of a living Podocarpus conifer tree
Fronds of living Polypodium ferns
Fossilized skeleton of the Eocene bony fish Pristigenys
A modern Pristipomoides snapper
Shell of a Pterynotus murex sea snail
A living Pagurus pollicaris hermit crab
Fossilized teeth of the Paleocene Palaeocarcharodon, or pygmy white shark
A living Perisoreus canadensis, or grey jay
Shell of a Petricolaria pholadiformis, or false angelwing
A living Plethodon, or woodland salamander
Restoration of the Paleocene-Eocene waterfowl Presbyornis
A taxidermied Prionodon, or Asiatic linsang
Illustration of a living Prionotus searobin
A living Puffinus shearwater
Illustration of a fossilized tooth in multiple views of the Early Cretaceous armored dinosaur Priconodon
Illustration of a fossilized tooth of the Early Cretaceous armored dinosaur Priconodon
Fossilized partial skeleton of the Early Jurassic theropod dinosaur Podokesaurus
Life restoration of the Early Jurassic theropod dinosaur Podokesaurus
A living Platyrhina ray
Fossilized skeleton of the Late Cretaceous-Eocene bony fish Pycnodus
Living Pinus strobus, or white pines
Taxidermied specimen of Pinguinus impennis, or the great auk
Fossilized shell of the Late Devonian ammonoid cephalopod Platyclymenia
Fossil of the Cambrian trilobite Ptychagnostus atavus
Fossils of the Cambrian trilobite Ptychoparia
Restoration of subadults of the Late Cretaceous dome-headed dinosaur Pachycephalosaurus butting heads
Restoration of the Cretaceous-Pleistocene frog Palaeobatrachus
Illustration of fossilized teeth of the Late Cretaceous armored dinosaur Palaeoscincus
Illustration of a fossilized skull of the Late Cretaceous armored dinosaur Panoplosaurus
Electron micrograph of the fossilized teeth in multiple views of the Late Cretaceous theropod dinosaur Paronychodon
Micrograph of a fossilized tooth of the Late Cretaceous troodontid Pectinodon
Fossilized skeleton of the Late Cretaceous primitive horned dinosaur Prenoceratops
Fossilized skeleton of the Late Cretaceous duck-billed dinosaur Prosaurolophus
Fossilized mandible of the Late Cretaceous-Paleocene mammal Protungulatum
Flowers and foliage of a living Paliurus
Restoration of the Paleocene pantodont mammal Pantolambda
Foliage of a living Paulownia plant
A living Peromyscus maniculatus, or North American deermouse
Stand of living Phragmites grasses
Restoration of the Miocene oreodont mammal Promerycochoerus
Restoration of the Late Cretaceous-Paleocene primate relative Purgatorius
Spiral-shaped fossilized burrow and associated skeleton of the Oligocene-Miocene beaver Palaeocastor
A living Pantherophis obsoletus, or black rat snake
A living Parascalops breweri, or hairy-tailed mole
A living Phasianus pheasant
Fossilized teeth of the Oligocene-Miocene oreodont mammal Phenacocoelus
Restoration of a female (left) and male of the Oligocene-Miocene even-toed ungulate Protoceras. Charles R. Knight (1896).
Fruit of a living Prunus maritima, or beach plum
A living Pylodictis olivaris, or flathead catfish
Fossilized skeleton of the Triassic bony fish Paralepidotus
Fossilized skeleton of the Triassic bony fish Paralepidotus
Life restoration of the Triassic ichthyosaur Phalarodon
Fossilized shell of the Early Jurassic ammonoid cephalopod Psiloceras
Fossilized shell of the Triassic ammonoid cephalopod Ptychites
Fossilized skeleton of the bony fish Ptycholepis
A living Pagurus hermit crab
Fossilized skull of the Late Cretaceous mosasaur Plioplatecarpus
Amber-entombed specimen of the Late Cretaceous wasp Plumalexius
Amber-entombed specimen of the Late Cretaceous wasp Plumalexius
Restoration of the Middle Triassic-Eocene crinoid ("sea lily") Pentacrinites
Fossil of the Devonian-Cretaceous sponge Peronidella
A living Phoca earless seal
A living Protula polychaete worm
Fossilized skull of the Eocene sea turtle Puppigerus. The shell belongs to another kind of turtle.
Fossilized skeleton of the Late Cretaceous duck-billed dinosaur Parasaurolophus
Fossilized crest from the skull of the Late Cretaceous duck-billed dinosaur Parasaurolophus
Life restoration of the Late Cretaceous duck-billed dinosaur Parasaurolophus being preyed upon by the tyrannosaur Teratophoneus
Restoration of the Late Cretaceous dome-headed dinosaur Prenocephale
Restoration of the Late Triassic turtle Proganochelys
A living Perognathus flavus, or silky pocket mouse
A living Peromyscus boylii, or brush mouse
A living Peromyscus eremicus, or cactus mouse
Fossil of the trilobite Paciphacops
Restoration of the Silurian-Devonian scorpion Palaeophonus
Fossil of the Silurian-Devonian scorpion Palaeophonus
Restoration of the Silurian-Devonian scorpion Palaeophonus
Fossil of the Silurian-Early Devonian eurypterid ("sea scorpion") Paracarcinosoma
Restoration of the Silurian-Early Devonian eurypterid ("sea scorpion")
Fossil of the Ordovician trilobite Paraceraurus
Fossils of the Silurian-Middle Devonian eurypterid ("sea scorpion") Parahughmilleria
Fossils of the Silurian-Middle Devonian eurypterid ("sea scorpion") Parahughmilleria
Fossilized body of the Silurian-Middle Devonian eurypterid ("sea scorpion") Parahughmilleria
Fossil of the Devonian trilobite Phacops rana
Fossils of the Devonian trilobite Phacops rana
Fossil in enrolled posture of the Devonian trilobite Phacops rana
Illustration of a fossil of the Cambrian arthropod Pseudoniscus
A living Pusa hispida, or ringed seal
A living Pagrus sea bream
A living Pagrus sea bream
A modern Pagrus sea bream
X-ray image of a modern Paragaleus weasel shark
Restoration of the Oligocene-Pleistocene false-toothed bird Pelagornis
A living Pelecanus, or pelican
Shell of a Perotrochus slit sea snail
Fossilized vertebra of the Miocene-Pleistocene baleen whale Plesiocetus
Illustration of a living Pomatomus saltatrix, or Bluefish
Living Pontederia pickerel weeds
A living Procellaria aequinoctialis, or white-chinned petrel
A living Pseudorca crassidens, or false killer whale
A living Ardenna gravis (formerly Puffinus gravis), or great shearwater
Fossilized skeleton of the Late Cretaceous dome-headed dinosaur Pachycephalosaurus
A living Philodendron
A living Platycarya tree
Fossil of the Devonian-Cretaceous sponge Peronidella
Illustration of a fossil of the Cambrian crustacean Protocaris
Restoration of the Oligocene-Miocene beaver Palaeocastor
A living Parrotia, or Persian ironwood
Restoration of the Oligocene false saber-toothed cat Pogonodon in a tree
Fruit of a living Pyrus, or pear tree
Fossilized cranium of the Oligocene-Miocene tapir Protapirus
Restorative portrait of the Oligocene-Miocene tapir Protapirus
Life restoration of the Late Cretaceous mosasaur Platecarpus
A living Pinicola enucleator, or pine grosbeak
Restoration of the Miocene-Pliocene red panda Pristinailurus, or Bristol's panda
A living Pleurostoma fungus
Shell of a Pleurotomella sea snail
Illustration in multiple views of the shell of a Polygyra land snail
Restorative models in multiple views of the Eocene brontothere Protitanotherium (figure 3)
A living Pseudacris ocularis, or little grass frog
A living Pseudacris streckeri, or Strecker's chorus frog
A living Plestiodon obsoletus (formerly Eumeces obsoletus), or Great Plains skink
Restorative portrait of the Early Jurassic synapsid (mammal precursor) Pachygenelus
Shell of a Pachymelania freshwater snail
Restoration of the Late Triassic phytosaur Paleorhinus
Fossilized skull in multiple views of the Early Cretaceous armored dinosaur Pawpawsaurus
Restoration of the Early-Late Cretaceous ichthyosaur Platypterygius
Life restoration of the Late Cretaceous mosasaur Plioplatecarpus
Illustration of a fossilized partial jaw of the Late Cretaceous plesiosaur Polyptychodon
Fossilized skull of the Permian amphibian Pantylus
Fossilized shell of the Permian ammonoid cephalopod Paraceltites
Life restoration of the Permian amphibian Pelodosotis
Restoration of the Cambrian shelled cephalopod Plectronoceras
A preserved Pachycondyla ant
A living Phalaenoptilus nuttallii, or common poorwill
Fossilized skeleton of the Paleocene-Eocene arowana relative Phareodus
A living Pipilo chlorurus, or green-tailed towhee
Restoration of the Eocene horse Protorohippus. F. John (1902).
Fossilized skeleton of the Paleocene-Eocene bird Pseudocrypturus
Illustration (figure 1) of a living Psilota hoverfly
A living Pupilla land snail
A living Petrochelidon pyrrhonota, or American cliff swallow
Life restoration of the Late Cretaceous plesiosaur Plesiopleurodon
Fossilized shells of the Late Ordovician-Early Devonian nautiloid cephalopod Plagiostomoceras
Restoration of the Carboniferous four-limbed animal Proterogyrinus
Life restoration of the Permian reptile Protorothyris
Restoration of the Early Triassic amphibian Parotosuchus
Illustration of a living Pistia, or water lettuce
Flowers of a living Polemonium, or Jacob's ladder
Fossilized skeleton of the Eocene creodont mammal Proviverra
A living Parus, or tit
Fruit of a living Phytolacca americana, or pokeberry


Restoration of the Silurian trilobite Proetus
Divider
A living Quercus virginiana, or southern live oak
A living Quiscalus major, or boat-tailed grackle
Shell of a Quinqueloculina foraminiferan
Restoration of a flock of the Late Cretaceous pterosaur Quetzalcoatlus feeding on the ground
A living Quadrula freshwater mussel
Fossilized skeleton of the Late Cretaceous pterosaur Quetzalcoatlus
A living Quiscalus, or grackle
Divider
  • A living Rana catesbeiana (sometimes Lithobates catesbeianus), or American bullfrog
  • Fossilized skull of the Late Triassic crocodile relative Revueltosaurus
  • Life restoration of the Late Triassic crocodile relative Revueltosaurus
  • Fossilized skeleton of the Late Triassic phytosaur Rutiodon
  • Illustration in multiple views of the fossilized skull of the Early Jurassic sauropodomorph dinosaur Sarahsaurus
  • Life restoration of the Early Jurassic primitive armored dinosaur Scutellosaurus
  • Life restoration of the Early Jurassic theropod dinosaur Segisaurus
  • Life restorations of two species of the Late Triassic phytosaur genus Smilosuchus with anachronistic humans to scale
  • Restoration of the Early-Late Cretaceous brachiosaur Sonorasaurus
  • Illustrations in multiple views of the skeleton of the Late Triassic aetosaur Stagonolepis
Fossil of the barnacle boring ichnogenus Rogerella
A living Rallus limicola, or Virginia rail
Restoration of the Miocene-Pliocene pronghorn Ramoceros and Cosoryx. Robert Bruce Horsfall (1913).
A living Rapana murex sea snail
A living Recurvirostra, or avocet
Living Reticulitermes termites
Fruit of a living Rhus, or sumac
A living Rissa tridactyla, or black-legged kittiwake
Flowers of a living Robinia
A living Raphidia snakefly
A living Rhagio snipefly
A living Rhagonycha soldier beetle
A living Rhamphomyia dance fly
A living Rhineura floridana, or North American worm lizard
A living Rhingia hoverfly
A living Rhyssa wasp
A living Rothschildia moth
A living member of Rubus, the genus including blackberries (pictured) and raspberries
Restoration of the Late Cretaceous-Paleocene ray Rhombodus
A living Rhincodon, or whale shark
A living Rallus elegans, or king rail
A living Lithobates grylio (formerly Rana grylio), or pig frog
A living Recurvirostra americana, or American avocet
A living Pine woods snake, or pine woods snake
A living Rhinoptera bonasus, or cownose ray
A living Rhizoprionodon terraenovae, or Atlantic sharpnose shark
Shell in multiple views of a Rissoa sea snail
Illustration of living Ruppia, or widgeonweeds
Living Regnellidium water ferns
Fossilized shell of the Triassic brachiopod Rhaetina
Shell of a Rhodea land snail
Restoration of the Middle Devonian placoderm fish Rhamphodopsis
A living Rhinocheilus lecontei, or long-nosed snake
A living Lithobates clamitans (sometimes Rana clamitans), or green frog
A living Rhynchobatus, or wedgefish
A living Morone saxatilis (formerly Roccus saxatilis), or striped bass
A living Rangifer, also known as a reindeer or Caribou
Micrograph with magnified inset of a fossilized tooth of the Late Cretaceous theropod dinosaur Richardoestesia
Restoration of the Late Cretaceous horned dinosaur Rubeosaurus
Living Ribes berries
Fossilized shell of the Late Triassic ammonoid cephalopod Rhacophyllites
Fossilized skeleton of the Late Triassic phytosaur Redondasaurus
Restoration of the Late Triassic phytosaur Rutiodon
Fossil of the Silurian eurypterid ("sea scorpion") Rhinocarcinosoma
Flower of a living Ranunculus, the genus including buttercups
Life restoration of the Permian amphibian Rhynchonkos
A living Regina, or crayfish snake
A living Raja texana also known as a roundel skate or Texas clearnose skate
Shell of a Raphitoma sea snail
A living Rhinocheilus lecontei, or long-nosed snake
Restoration of the Permian amphibian Rubeostratilia
Restoration of the Early Devonian primitive vascular plant Renalia
A living Rhinoclemmys, or Neotropical wood turtle
Divider
  • A living Salix, or willow
  • Several views of the shell of a Sinum moon snail
  • A living Sorex, or long-tailed shrew
  • Restoration of the Carboniferous amphibian Sauropleura
  • Fossilized stump of the Carboniferous-Permian club moss relative Sigillaria
  • Fossil of the Carboniferous-Permian club moss relative Sigillaria
  • Modern specimen of the marine bivalve Solemya
  • Fossilized leaves and branches of the Devonian-Triassic horsetail relative Sphenophyllum
  • Fossilized foliage of the Late-Devonian-Cretaceous seed fern Sphenopteris
  • Fossilized holdfast of the Cambrian-Carboniferous conulariid Sphenothallus
  • Fossilized shell of the Late Ordovician-Late Triassic brachiopod Spirifer
  • Restorations of two species of the Late Devonian-Carboniferous Chimaera relative Stethacanthus, S. altonensis (above) and S. productus (below)
  • Restorations of a male (foreground) and female (background) of the Late Devonian-Carboniferous Chimaera relative Stethacanthus
  • Fossilized shell of the Ordovician-Silurian brachiopod Strophomena
  • Fossilized shell of the Ordovician-Silurian brachiopod Strophomena
  • Fossil of the Devonian tabulate coral Syringopora
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Scaphites
  • A living Selaginella, or spikemoss
  • Fossilized skeleton of the Late Triassic-Early Jurassic bony fish Semionotus
  • Restoration of the Late Cretaceous shark Squalicorax
  • Restoration of the Late Jurassic stegosaur Stegosaurus
  • Restoration of the primitive tyrannosaur Stokesosaurus
  • Restoration in multiple views of the Late Jurassic sauropod dinosaur Supersaurus with an anachronistic human to scale
  • Restoration of the Late Jurassic sauropod dinosaur Supersaurus with an anachronistic human to scale
  • Assemblage of fossils of the Ordovician-Triassic blue-green alga Sphaerocodium
  • Fossilized shell and lophophore of the Silurian-Middle Jurassic brachiopod Spiriferina
  • Modern shells of the polychaete worm Spirorbis
  • Fossilized shell of the Middle Devonian brachiopod Stringocephalus
  • Fossilized leaf of the Triassic-Early Cretaceous seed fern Sagenopteris
  • Fossil of the Cretaceous dinosaur footprint ichnogenus Saurexallopus
  • Exterior and interior of the shell of a Scurria limpet
  • Fossilized shells of the marine bivalve Solecurtus
  • Fossilized leaf of the Late Cretaceous ginkgo relative Sphenobaiera
  • Fossil of the Carboniferous-Permian tree-like club moss relative rhizome Stigmaria
  • Fossil preserved in situ of a Carboniferous tree-like club moss relative with attached Stigmaria rhizome system
  • Fossil of the Carboniferous-Permian tree-like club moss relative rhizome Stigmaria
Fossil of the Middle Ordovician-Silurian trilobite Sphaerexochus
Life restoration of the mysterious Ediacaran animal Swartpuntia
Fossilized shell of the Late Cretaceous ammonoid cephalopod Scalarites
Base of the trunk of a living Sequoia tree with a human to scale
Diagram illustrating the sizes of the Late Triassic ichthyosaurs Shonisaurus popularis (green) and S. sikanniensis (red) with an anachronistic human to scale
Restoration of three species of the Middle-Late Triassic ichthyosaur genus Shastasaurus
Restorations of two species of the Early Cretaceous ammonoid cephalopod Shastoceras
Fossils of the Cambrian-modern worm burrow ichnogenus Skolithos
Life restoration of the Late Cretaceous shark Squalicorax
Living Sabal, or palmettos
Fossilized skeleton of the Eocene monitor lizard Saniwa
Fossilized teeth of the Neogene sperm whale Scaldicetus
A living Scapanus latimanus, or broad-footed mole
Fossilized jaw and teeth of the Miocene horse Scaphohippus
A living Sceloporus occidentalis, or western fence lizard
A living Sciurus squirrel
A living Scomberesox saury
Illustration of a living Scopelogadus ridgehead
A living Sebastes, the genus including the rockfishes and sea perches
A living Semicassis helmet sea snail
Fossilized skull of the Pliocene porpoise Semirostrum
A living Sequoiadendron
Restoration of two species of the Oligocene oreodont mammal genus Sespia
A living Sigmodon, or cotton rat
A living Siliqua patula, or Pacific razor clam
Shell in multiple views of a Skenea californica, or California skenea
Diagram illustrating at scale various species of the Pleistocene-Holocene saber-toothed cat genus Smilodon; S. populator (green), S. fatalis (purple), and S. gracilis (orange) with a human
A living Otospermophilus beecheyi (formerly Spermophilus beecheyi), or California ground squirrel
A living Callospermophilus lateralis (formerly Spermophilus lateralis), or golden-mantled ground squirrel
A living Squalus, or spurdog
A living Squatina californica, or Pacific angelshark
Fossilized skeleton of the Miocene weasel Sthenictis
Fossilized skeleton of the fossil pronghorn Stockoceros
Shell in two views of Lobatus galeatus (formerly Strombus galeatus), or Eastern Pacific giant conch. Louis Charles Kiener (1843).
Fossilized skeleton of the Eocene-Oligocene tortoise Stylemys
Restoration of the Eocene-Oligocene cow-sized rhinoceros Subhyracodon. Charles R. Knight (1890s).
A living Sylvilagus audubonii, or desert cottontail
A living Syngnathus pipefish
A living Synthliboramphus antiquus, or ancient murrelet
A living Synthliboramphus hypoleucus, or Guadalupe murrelet
Fossilized skeleton of the Permian primitive four-limbed animal Seymouria
A living Saperda flat-faced longhorn beetle
A living Sceloporus undulatus, or eastern fence lizard
Adult, larva, and pupa of a living Scolytus bark beetle
Fossilized branch fragment from a Sequoia affinis
Restorative model of the Eocene horse Sifrhippus
Restoration of the Paleocene mesonychid mammal Sinonyx (top)
A living Sitona weevil
Fossilized skeleton of the Eocene primate Smilodectes
A living Spea bombifrons, or plains spadefoot toad
A living Urocitellus richardsonii (Spermophilus richardsonii), or Richardson's ground squirrel
Restoration of the Eocene brontothere mammal Sphenocoelus
A living Spizella breweri, or Brewer's sparrow
A living Staphylea, or bladdernut
A living Stenolophus ground beetle
Ripe fruit capsule and seeds of a living Sterculia, or tropical chestnut
Living Stipa, or feather grass
Life restoration of the Eocene taeniodont mammal Stylinodon
A living Sylvilagus, or cottontail rabbit
Fossilized skull of the Miocene toothed whale Schizodelphis
Restoration of the Oligocene-Miocene shark-toothed dolphin Squalodon
Living Sabal palmetto
A living Sardinella
Developmental series of shells of Scaphella junonia, or the Juno's volute sea snail
A living Scaphiopus holbrookii, or eastern spadefoot toad
A living Sciurus carolinensis, or eastern gray squirrel
Shell in multiple views of a Semicassis granulata, or Scotch bonnet sea snail
Living Serenoa, or saw palmetto
Living Siderastrea siderea, or massive starlet coral
A living Sigmodon hispidus, or hispid cotton rat
A living Simnia false cowrie
A living Siren lacertina, or greater siren
A living Sistrurus miliarius rattlesnake
Shell of a Solariella top sea snail
A living Somateria spectabilis, or king eider
A living Sorex longirostris, or southeastern shrew
A living Sphyraena barracuda, or great barracuda
A living Spizaetus, or typical hawk-eagle
Shell of a Spondylus americanus, or Atlantic thorny oyster
A living Stellifer, or stardrum
A living Sternotherus, or musk turtle
Shell of a Stramonita murex sea snail
Shell of a Strioterebrum augur sea snail
Shell of a Strobilops land snail
Shell of a Strombina dove sea snail
A living Strombus alatus, or Florida fighting conch
Fossilized shell in multiple views of a Strombus alatus, or Florida fighting conch
A living Sturnella magna, or eastern meadowlark
Shell of a Subcancilla sea snail
A living Sylvilagus palustris, or marsh rabbit
Illustration of a living Synaptomys, or bog lemming
A living Synodus foetens, or inshore lizardfish
A living Squatina, or angel shark
Close-up portrait of a Siren intermedia, or lesser siren
A living Sphyrna tiburo, or bonnethead shark
A living Synodus lizardfish
Fossil of the Cambrian priapulid worm Selkirkia
Fossil of the Carboniferous colonial rugose coral Siphonodendron
Fossilized skeleton of the Early Triassic-Middle Jurassic bony fish Saurichthys
Fossilized skeleton of the Early Triassic-Middle Jurassic bony fish Saurichthys
Restoration of the Early Triassic-Middle Jurassic bony fish Saurichthys preying upon a pterosaur
Fossilized shell of the Middle Jurassic ammonoid cephalopod Stephanoceras
Reconstruction of a fossilized skull and restorative portrait of the Miocene-Pliocene red panda relative Simocyon
Restorative portrait of the Miocene-Pliocene red panda relative Simocyon
Fossilized leaves and branches of the Devonian-Triassic horsetail relative Sphenophyllum
Diagram illustrating the Late Devonian-Carboniferous Chimaera relative Stethacanthus with an anachronistic human to scale
Life restoration of the Late Devonian-Carboniferous Chimaera relative Stethacanthus
Life restoration of the Carboniferous Chimaera relative Symmorium
Fossil of the Carboniferous Chimaera relative Symmorium
Fossilized calyx of the Carboniferous crinoid ("sea lily") Scytalocrinus
Restoration of the Carboniferous reptile Spinoaequalis
Illustration of a fossilized cranium of the Late Cretaceous armored dinosaur Silvisaurus
Animated Restoration of the Late Cretaceous plesiosaur Styxosaurus
A living Scaphiopus, or North American spadefoot toad
Fossilized partial cranium of the Soergelia mayfieldi, or Soergel's ox
A living Sorex palustris, or American water shrew
A living Ictidomys tridecemlineatus (formerly Spermophilus tridecemlineatus), or thirteen-lined ground squirrel
Shells in differing orientations of Sphaerium freshwater clams
Illustration of a living Novisuccinea ovalis (formerly Succinea ovalis), or amber oval land snail
A living Sylvilagus floridanus, or eastern cottontail
Shell of a Scaphella volute sea snail
A living Sciaena umbra, or brown meagre
Fossils of the Ordovician-Silurian brittle star Stenaster
Fossilized teeth of the Cretaceous-Eocene shark Serratolamna
Illustration of living Schizoporella unicornis bryozoans ("moss animals")
A living Sorex cinereus, or cinereus shrew
A living Squatina, or angelshark
Illustration of a living Squilla empusa mantis shrimp
A living Synaptomys cooperi, or southern bog lemming
Fossils of the Cambrian mollusc Scenella
Restoration of the Early Cretaceous armored dinosaurs Sauropelta
Fossilized cranium in multiple views of the Late Cretaceous armored dinosaur Scolosaurus
Fossils of the dinosaur egg oogenus Spheroolithus
Restoration of the Late Cretaceous horned dinosaur Spiclypeus
Fossilized skull of the Late Cretaceous dome-headed dinosaur Stegoceras
Fossilized skeleton of the Late Jurassic long-necked dinosaur Suuwassea
Fossilized bones of the Paleocene-Eocene choristoderan reptile Simoedosaurus
Fossilized partial skulls of the rodent Oligocene-Miocene Steneofiber
Restoration of the Miocene deer relative Subdromomeryx. Robert Bruce Horsfall (1913).
A living Scalopus aquaticus, or eastern mole
Illustration of fossilized shells of the mysterious Cambrian organism Salterella
Fossilized shell of the Early Jurassic ammonoid cephalopod Schlotheimia
Fossilized skull of the Late Triassic giant ichthyosaur Shonisaurus
Diagram illustrating Shonisaurus (green) and Shastasaurus sikanniensis (red) with an anachronistic human to scale
Restoration of the Late Triassic giant ichthyosaur Shonisaurus
Closeup view of an amber-entombed specimen of the Late Cretaceous ant Sphecomyrma
Amber-entombed specimen of the Late Cretaceous ant Sphecomyrma
Flower of a living Stewartia
Restoration of the Late Cretaceous duck-billed dinosaur Saurolophus
Restoration of the Late Triassic distant crocodilian relative Shuvosaurus
Life restoration of the Late Triassic aetosaur Stagonolepis
Restoration of the Late Cretaceous dome-headed dinosaur Stegoceras
Restoration of the Late Cretaceous ostrich dinosaur Struthiomimus
Fossilized skeleton of the Eocene-Oligocene creodont mammal Sinopa
Fossilized shell of the Cambrian-Late Ordovician mollusc Scenella
Fossils of the Cambrian trilobite Serrodiscus
Fossil of the Silurian eurypterid ("sea scorpion") Slimonia
Restoration of the Silurian eurypterid ("sea scorpion") Slimonia
Restoration of the Silurian eurypterid ("sea scorpion") Slimonia
Fossil of the burrow ichnogenus Spirorhaphe
Restoration of the Devonian eurypterid ("sea scorpion") Stylonurus
Living Sanguisorba canadensis, or Canadian burnet
Illustration of a living Sarda sarda, or Atlantic bonito
A living Scoliodon, or spadenose shark
A living Seriola, or amberjack
A living Somateria mollissima, or common eider
A modern Sphoeroides pufferfish
A living Sphyrna lewini, or scalloped hammerhead
A living Stenella, or oceanic dolphin
Illustration of a living Stenotomus chrysops, or scup
Illustration of a living Stercorarius longicaudus, or long-tailed jaeger. Johann Friedrich Naumann
A living Thalasseus maximus, or royal tern
A living Symphurus tonguefish
Restoration of the Permian reptile relative Seymouria
Fossilized skeletons of the Permian reptile relative Seymouria
Restoration of a pair of the Permian reptile relative Seymouria
Restoration of the Late Jurassic theropod dinosaur Saurophaganax
Diagram illustrating the size of the Early Cretaceous long-necked dinosaur Sauroposeidon, with an anachronistic human to scale
Fossilized partial skull in multiple views of the Middle-Late Triassic ichthyosaur Shastasaurus
Fossilized shell of the Early Cretaceous ammonoid cephalopod Spitidiscus
Fossilized fin of the Devonian lobe-finned fish Sauripterus
Fossil of the Early Devonian primitive vascular land plant Sciadophyton
Restorative model of the Cambrian arthropod Sidneyia
Fossils of the Cambrian arthropod Sidneyia
Shell of a living Saxidomus gigantea, or butter clam
A living Somatochlora dragonfly
A living Stercorarius, or skua
Fossilized tooth of the Late Cretaceous shark Squalicorax
Fossil of the Cambrian-Ordovician trilobite Saukiella
Fossilized calyx and partial stem of the Silurian crinoid ("sea lily") Sagenocrinites
Fossils of the Cambrian-modern worm burrow ichnogenus Skolithos
Shell of a Siphonaria false limpet sea snail
A living Sylvilagus aquaticus, or swamp rabbit
Shell of a Sassia triton sea snail
A living Siren salamander
A living Xerospermophilus spilosoma, or spotted ground squirrel
Shells in differing orientations of Stagnicola freshwater snails
Diagram illustrating the Early Cretaceous long-necked dinosaur Sauroposeidon with anachronistic humans to scale
Fossilized snout of the Late Cretaceous ray relative Sclerorhynchus
A living Squalus, or spurdog
Restorative portrait of the Permian synapsid (mammal precursor) Secodontosaurus
Life restoration of the Late Devonian-Permian Sphenacanthus
Restorative portrait of the Permian synapsid (mammal precursor) Steppesaurus
Diagram illustrating the maxilla of the Permian synapsid (mammal precursor) Steppesaurus compared to a cranium of Sphenacodon
Fossils of the seafloor animal trail ichnogenus Scolicia
Life restoration of the Carboniferous-Permian synapsid (mammal precursor) Sphenacodon
Foliage of a living Sassafras tree
Foliage of a living Schoepfia
A living Sialia, or bluebird
A living Sloanea tree
Foliage and fruit of a living Smilax
A living Sturnella neglecta, or western meadowlark
Flowers and foliage of a living Styrax, also known as storax or snowbel
Restoration of the Miocene protoceratid mammal Syndyoceras
A living Seiurus aurocapilla, or ovenbird
A living Sialia sialis, or eastern bluebird
A living Squalus , or spurdog
A living Sturnella meadowlark
A living Sylvilagus transitionalis, or New England cottontail
A living Setophaga coronata, or yellow-rumped warbler
Known material diagram of the Early Jurassic primitive long-necked dinosaur Seitaad
Life restoration of the Late Cretaceous theropod dinosaur Siats
A living Spatula discors (formerly Anas discors), or blue-winged teal
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  • Restoration of the Miocene-Pliocene rhinoceros Teleoceras
  • Illustration of a living Trechus ground beetle
  • Fossilized shells of the Late Jurassic-modern tower snail Turritella
  • Fossil of the feeding trace ichnogenus Teichichnus
  • Assemblage of fossilized shells of the Early Ordovician-Late Devonian probable mollusc Tentaculites
  • Fossilized shell of the Early Ordovician-Late Devonian probable mollusc Tentaculites
  • Fossilized shell of the Ordovician nautiloid cephalopod Treptoceras
  • Fossil of the Late Ordovician trilobite Triarthrus
  • Restoration showing the top (left) and underside of the Late Ordovician trilobite Triarthrus
  • Fossil of the Late Ordovician trilobite Triarthrus
  • Life restoration of the Carboniferous amphibian Tuditanus
  • Fossilized skeleton of the Late Cretaceous plesiosaur Thalassomedon
  • Fossilized skulls of the Late Cretaceous horned dinosaurs Torosaurus (A) and Triceratops (B) to scale
  • Fossilized skeleton of the Late Cretaceous polycotylid plesiosaur Trinacromerum
  • Life restoration of the Late Cretaceous mosasaur Tylosaurus
  • Fossilized skeleton of the Late Cretaceous tyrannosaur Tyrannosaurus
  • Illustration in side view of several fossils of the Cambrian burrow ichnogenus Treptichnus
  • Fossil of the Cambrian burrow ichnogenus Treptichnus
  • Fossils of the burrow ichnogenus Thalassinoides
  • Fossilized skeleton of the Late Cretaceous sea turtle Toxochelys
  • Fossilized shell of a Trachycardium cockle
  • Fossilized skeleton of the Late Cretaceous mosasaur Tylosaurus
  • Restoration of the Late Cretaceous mosasaur Tylosaurus
  • Fossils of the Devonian plant stem morphogenus Taeniocrada
  • Fossils of the Devonian plant stem morphogenus Taeniocrada
  • Fossils of the Early-Late Ordovician graptolite Tetragraptus
  • Fossil preserving limbs and antennae as pyrite (fool's gold) of the underside of the Late Ordovician trilobite Triarthrus
  • Fossils of the ichnogenus Teredolites, produced by bivalves boring into wood.
  • Fossilized shell of the Permian-Paleocene marine bivalve Trigonia
  • Fossilized skeleton found in Alaska of the Late Cretaceous troodontid Troodon
  • Life restoration of the Carboniferous-Triassic freshwater shark Triodus
  • Fossilized skeleton of the Early Cretaceous Iguanodon relative Tenontosaurus
  • Restoration of the Early Cretaceous Iguanodon relative Tenontosaurus
  • Fossilized skeleton of the Late Triassic reptile Trilophosaurus.
  • Restoration of the Late Triassic reptile Trilophosaurus with an anachronistic human to scale
  • Restoration of a pair of the Late Triassic aetosaur Typothorax
  • Restoration of the Pleictocene pronghorn Tetrameryx
Fossils of the bore-hole ichnogenus Trypanites
Illustration of a fossil of the Cambrian trilobite Trinodus
A living Terebralia horn sea snail
Reconstructed skull in side (above) and top view of the Late Triassic thalattosaur Thalattosaurus. The frontmost portion of the snout is portrayed erroneously as straight; it actually had a pronounced downward curve
Diagram of the anatomy of a Trigonia marine bivalve
Fossilized shell in multiple views of the Early-Late Cretaceous sea snail Trochactaeon
Fossilized shell of the Late Cretaceous ammonoid cephalopod Turrilites
Illustration in multiple views of fossilized shells belonging to the Jurassic-modern tower shell sea snail Turritella
Flower of a living Tabernaemontana, or milkwood
Restoration of the Eocene carnivoran relative Tapocyon
A living Tayassu pecari, or white-lipped peccary, with offspring
Restoration of the Pleistocene bird of prey Teratornis
Fossilized shell in two views of the Late Devonian-modern brachiopod Terebratula
Restoration of the Miocene fur seal Thalassoleon
Close-up portrait of a living Thomomys bottae, or Botta's pocket gopher emerging from its burrow
A school of living Thunnus, or tunas
Fossilized skull of the Miocene oreodont mammal Ticholeptus
Fossilized skeleton of the Miocene-Pleistocene camel Titanotylopus
Fossilized skull of the Miocene bone-crushing dog Tomarctus
Foliage of living Toxicodendron
A living Toxopneustes roseus, or rose flower urchin. The object on top of the animal is a piece of coral rubble.
A living Tremarctos, or spectacled bear
A living Triakis houndshark
A living Triplofusus spindle sea snail
Shell of a Tucetona bittersweet clam
Shell of a Turbonilla laminata pyram shell sea snail
Shell of a Turcica sea snail
Shell of a Turritriton gibbosus triton sea snail
A living Tursiops, or bottlenose dolphin
Fossil of the Silurian-Carboniferous crinoid ("sea lily") Taxocrinus (right)
Close-up portrait of a living Tabanus horsefly
A living Tachycineta bicolor, or tree swallow
A living Tamiasciurus hudsonicus, or American red squirrel
A living Tanysphyrus lemnae weevil
Fossilized mandible of the Eocene primate Teilhardina
A living Tenthredo sawfly
A living Tetragnatha spider
Living Batagur turtles
A living Thamnophis elegans, or western terrestrial garter snake
A living Thanasimus checkered beetle with prey
A living Themira black scavenger fly
A living Thomisus crab spider
A living Thomomys, or smooth-toothed pocket gopher
A living Thuja tree
A living member of Tilia, the genus including the lindens and basswoods
A living Tipula crane fly
Life restoration of the Paleocene pantodont mammal Titanoides
Foliage of a living Torreya, or nutmeg yew
A living Tortrix moth
Fruits and foliage from a modern Trichilia
Restoration of the Eocene creodont mammal Tritemnodon
A living Tropisternus water scavenger beetle
A living Trox hide beetle
Living Typha, or cattails
A living Tachybaptus dominicus, or least grebe
A living Tamias chipmunk
Shell of a Tectonatica pusilla moon sea snail
Shell in multiple views of a Tegula fasciata, or Smooth Atlantic Tegula
Fossilized skeleton of the Pleistocene bird of prey Teratornis
Shell in multiple views of a Terebra dislocata, or eastern auger sea snail
A living Terrapene, or box turtle
A living Terrapene carolina, or common box turtle
Living Thalassia testudinum, or turtlegrass
Illustration of living Thalassodendron sea grass
Fossilized skeleton of the Miocene-Pliocene ground sloth Thinobadistes
Fossilized skeleton of the Pliocene-Pleistocene terror bird Titanis
Life restoration of the Pliocene-Pleistocene terror bird Titanis
A living Toxostoma rufum, or brown thrasher
A living Trachemys scripta, or pond slider
Shell of a Trachycardium egmontianum, or the Florida prickly cockle
Exterior and interior of the shell of a Trachycardium isocardia, or West Indian prickly cockle
A living Trichechus manatus, or West Indian manatee
Shell of a Tricolia pheasant shell sea snail
A living Tringa melanoleuca, or greater yellowlegs
A living Tringa solitaria, or solitary sandpiper
A living Triplofusus papillosus, or Florida horse conch
A living Troglodytes aedon, or house wren
Close-up portrait of a living Tropidophis, or West Indian wood snake
Shell of a Turbo castanea, or chestnut turban sea snail
Shell of a Turbonilla hemphilli pyram sea snail
Shell in multiple views of a Tutufa frog shell sea snail
Close-up portrait of a living Typhlops blind snake
Fossil of the Cambrian trilobite Tricrepicephalus
Fossilized skull of the Late Cretaceous-Paleocene gavial relative Thoracosaurus
Fossil of the Cambrian trilobite Thoracocare
Restoration of the Cretaceous tree-like fern Tempskya
Part and counterpart fossils of the mysterious Carboniferous life-form Tullimonstrum, or the Tully monster
Restoration of the mysterious Carboniferous life-form Tullimonstrum, or the Tully monster
Fossil of the mysterious Carboniferous life-form Tullimonstrum, or the Tully monster
A living Thamnophis radix, or plains garter snake
A living Tympanuchus, or prairie chicken
Stand of living Taxodium cypresses
A living Tectonatica moon sea snail
A living Tamias striatus, or eastern chipmunk
Fossilized skeleton of the Paleocene-Eocene sea turtle Tasbacka
Fossilized skeleton of the Oligocene-Miocene gavial relative Thecachampsa
Fossil of the mysterious Cambrian animal Torellella
Illustration of a fossilized shell in multiple views of the Silurian monoplacophoran mollusc Tryblidium reticulatum. Head region is to the left.
Fossilized skull of the Late Cretaceous crocodilian relative Terminonaris
Restoration of the Late Cretaceous herbivorous dinosaur Thescelosaurus
Fossilized teeth of the Late Cretaceous duck-billed dinosaur Trachodon
Fossilized skeleton of the Late Cretaceous horned dinosaur Triceratops
Illustration of fossilized teeth of the Late Cretaceous Troodon
Restoration of the Paleocene multituberculate mammal Taeniolabis
A living Thomomys talpoides, or northern pocket gopher
Restoration of the Paleocene pantodonts mammal Titanoides
Seeds of a modern Trapa, or water caltrop
Living Terrapene ornata, or western box turtles
A living Thamnophis radix, or plains garter snake
Fossilized shell of the Cambrian arthropod Tuzoia
Fossilized shell of the Cambrian arthropod Tuzoia
Restoration of the Middle Triassic ichthyosaur Thalattoarchon
Fossil of the Triassic-Eocene stony coral Thamnasteria
A living Trichechus, or manatee
Restoration of the Late Triassic theropod dinosaur Tawa
Fossilized skeleton of the Late Cretaceous horned dinosaur Titanoceratops
Restoration of the Paleocene multituberculate mammal Taeniolabis
Fossilized jaw of the Eocene brontothere mammal Telmatherium
Fossilized partial skull of the Paleocene mesonychid mammal Triisodon
Exterior and interior of the shell of a Tagelus marine bivalve
Diagram of the branches of the Middle-Late Devonian vascular plant Tetraxylopteris
Fossilized shell of the Middle-Late Devonian nautiloid cephalopod Trochoceras
Illustration of a living Thunnus thynnus, or Atlantic bluefin tuna
A living Triaenodon obesus, or whitetip reef shark
Fossilized skull of the Permian amphibian Trimerorhachis
Fossilized skull of the Permian amphibian Trimerorhachis
Fossilized skull of the Permian amphibian Trimerorhachis
Illustration of a fossilized skull in multiple views of the Permian amphibian Trimerorhachis Edward Drinker Cope.
Foliage and cones of a living Tetraclinis, or arar tree
Shell of a Thesbia sea snail
Shell of a Trichotropis cap sea snail
A living Tympanuchus pallidicinctus, or lesser prairie chicken
A living Tursiops truncatus, or common bottlenose dolphin
Shell of a Thylacodes worm shell sea snail
A living Tropidoclonion, or lined snake
A living Truncilla truncata freshwater mussel, or Deertoe
Restoration of the Late Cretaceous plesiosaur Trinacromerum
Fossil of the Carboniferous crustacean Tesnusocaris
Fossilized skull in multiple views of the Permian synapsid (mammal precursor) Tetraceratops
Restorative portrait of the Permian synapsid (mammal precursor) Tetraceratops
Restoration of the Permian synapsid (mammal precursor) Tetraceratops
Restoration of the Carboniferous-Permian trilobite Triproetus
Restoration of the Permian reptile relative Tseajaia
Fossilized partial cranium of the Eocene brontothere mammal Telmatherium
A modern uprooted Thelypteris, or maiden fern
Fossil of the Eocene giant ant Titanomyrma with a preserved rufous hummingbird for scale
Illustration of a living Tritoma pleasing fungus beetle
Leaf and flowers of a living Triumfetta, or burbark
A living Trypodendron ambrosia beetle
A living Tympanuchus phasianellus, or sharp-tailed grouse
Illustration of a living Thyrsopteris tree fern
Restoration of the Late Cretaceous horned dinosaur Torosaurus
Fossilized teeth of the Late Cretaceous theropod dinosaur Troodon
Restoration of the Silurian arthropod Thylacares
A living Triodopsis tridentata land snail, or northern threetooth
Known material diagram of the Late Cretaceous troodontid Talos
Restoration of the Late Jurassic theropod dinosaur Tanycolagreus
Known material diagram of the Late Cretaceous tyrannosaur Teratophoneus
Fossilized skeleton of the Late Jurassic megalosaur Torvosaurus
Fossil of the Late Cretaceous tyrannosaur footprint ichnogenus Tyrannosauripus
Fossils of the bore-hole ichnogenus Trypanites
Restoration of the Late Jurassic megalosaur Torvosaurus
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  • Fossilized skeleton found in Alaska of the Late Cretaceous duck-billed dinosaur Ugrunaaluk
A living Urocyon cinereoargenteus, or gray fox
A living Uca, or fiddler crab
Restoration of the Eocene mammal Uintatherium
A pair of living Uria aalge, or common murre
A living Uta stansburiana, or common side-blotched lizard
A living Uca pugnax, or Atlantic marsh fiddler crab
Fossils of the Late Cretaceous crinoid ("sea lily") Uintacrinus
Fossilized calyx ad partial stem of the Carboniferous crinoid ("sea lily") Ulrichicrinus
A living Umbrina croaker
Living Uria, also known as murres of guillemots
A modern Urophycis hake
A living Ursus arctos, or brown bear
Life restoration of the Carboniferous amphibian Utaherpeton
Fossilized jaws of the Late Devonian lungfish Uranolophus
Restoration of the Late Cretaceous horned dinosaur Utahceratops
Diagram illustrating the Early Cretaceous dromaeosaurid ("raptor") Utahraptor with an anachronistic human to scale
Fossilized skeleton of the Late Jurassic Iguanodon relative Uteodon
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  • Life restoration of the Late Triassic reptile Vancleavea
  • Leaves and fruit of a living Vitis, or grapevine
  • Fossilized shell of the Late Cretaceous ammonoid cephalopod Vascoceras
  • A variety of modern Vaccinium species, clockwise from top right: cranberries, lingonberries, blueberries, and huckleberries
  • A living Vulpes vulpes, or red fox
  • Fossilized shell of the Jurassic-modern Vermetus, or worm shell sea snail
  • Restoration of the Permian trilobite Vidria
A living Vasum, or vase sea snail
Branches and foliage of a living Vauquelinia, or rosewood
Fossilized shell of the Paleocene-Miocene nerite sea snail Velates
Shell of a Velutina velutina or velvet shell sea snail
A living Vireo
A living Voluta sea snail
Fossilized skeleton of the Eocene mammal Vulpavus
Fossilized shell in multiple views of the Pleistocene shaggy vase sea snail Hystrivasum horridum (formerly Vasum horridum)
Shell in multiple views of a Vasum muricatum, or Caribbean vase sea snail
A living Oreothlypis celata (formerly Vermivora celata), or orange-crowned warbler
Shell of a Vertigo milium, or blade vertigo land snail
Flowers of a living Viburnum dentatum, or southern arrowwood
A living Vireo griseus, or white-eyed vireo
Fruit and foliage of living Vitis rotundifolia, or muscadine grape vines
Shell of a Viviparus georgianus, or banded mystery snail
Shell in multiple views of a Vokesimurex rubidus, or rose murex sea snail
A living Vespertilio bat
Shell in multiple views of a Volema crown conch
Restorations of the Late Cretaceous marine bivalve Volviceramus
Shell of a Viviparus freshwater snail
Fossilized skeleton of the Permian synapsid (mammal precursor) Varanops
Restoration of the Permian synapsid (mammal precursor) Varanops
Restoration of the Permian synapsid (mammal precursor) Varanops
A living Vallonia land snail
Opening of the shell of a Vertigo ovata land snail, or ovate vertigo
Fossilized skeleton of the Permian synapsid (mammal precursor) Varanosaurus
Fossil of the Cambrian-Silurian sponge Vauxia
Fossilized skeleton of the Eocene bony fish Voltaconger
A living Valvata freshwater snail
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  • Fossilized foliage of the Carboniferous-Permian conifer Walchia
  • Fossilized trunk of the Carboniferous-Permian conifer Walchia
  • Restoration of the Permian shark Wodnika
Fossil of the Cambrian trilobite Wanneria
Flowers of a living Weinmannia
Fossils (figures 1-5) of the Silurian eurypterid ("sea scorpion") Waeringopterus
Fossilized head of the Silurian eurypterid ("sea scorpion") Waeringopterus
Living Woodwardia ferns
Fossilized roots of the Middle Devonian tree Wattieza
Fossilized skeleton of the Paleocene Alligator relative Wannaganosuchus


Fossilized partial skull of the Early Cretaceous crocodilian Wannchampsus with a modern Crocodylus porosus skull in the background for comparison
Fossilized partial skulls of the Early Cretaceous crocodilian Wannchampsus
Restoration of the Cambrian arthropod Waptia
Restoration of the Cambrian possible mollusc Wiwaxia
Fossils of the Middle Jurassic-Early Cretaceous fern Weichselia
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  • Illustration of a fossil of the Carboniferous millipede Xyloiulus
  • Restoration of the Cretaceous bony fish Xiphactinus
Fossilized shells of the ammonoid cephalopod Xenodiscus
Fossilized shell of the Late Cretaceous-modern carrier shell sea snail Xenophora
A living Xantholinus rove beetle
A living Xestobium beetle
A living Xylocopa, or carpenter bee
Shell of a Xenophora conchyliophora carrier shell sea snail
Fossilized skeleton of the Pleistocene saber-toothed cat Xenosmilus
Fossilized skeleton of the Miocene whale Xiphiacetus
A living Xiphias, or swordfish
Reconstructed skeleton of the Late Devonian-Triassic shark Xenacanthus
A living Xanthocephalus xanthocephalus, or yellow-headed blackbird
Restoration of the Late Devonian–Triassic freshwater shark Xenacanthus
A living Xema sabini, or Sabine's gull
Fossilized skull of the Pliocene-Pleistocene wolf Xenocyon
Fossilized skeleton of the Late Devonian–Triassic freshwater shark Xenacanthus
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Shell of a Yoldia limatula, or file yoldia
Life restoration of the Miocene bear dog Ysengrinia
Restoration of the probable Cambrian mollusc Yochelcionella
Life restoration of the Early Cretaceous dromaeosaurid ("raptor") Yurgovuchia
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  • Fossil of the feeding trace ichnogenus Zoophycos
  • Life restoration of the Eocene whale Zygorhiza
  • Shell in multiple views of a Zebina sea snail
A living Zalophus californianus, or California sea lion
Fossil of the Early Triassic-Eocene cycad-like frond Zamites
Restoration of the Miocene snake mackerel relative Euzaphleges
Known material diagram depicting the Miocene-Pleistocene mastodon relative Zygolophodon with a human to scale
A living Zamia cycad
A living Zonotrichia leucophrys, or white-crowned sparrow
A living Zapus hudsonius, or meadow jumping mouse
Leaf of a living Zelkova tree
Micrograph with magnified inset of a fossilized tooth of the Late Cretaceous theropod dinosaur Zapsalis
Fossilized cranium of the Miocene-Pleistocene mastodon relative Zygolophodon
A living Zygaena moth
Restoration of the Late Cretaceous armored dinosaur Ziapelta
Restoration of the Late Cretaceous primitive horned dinosaur Zuniceratops
A living Zenaida dove
Fossil of the polychaete worm feeding trace ichnogenus Zoophycos
Illustration of a living Ziphius cavirostris, or Cuvier's beaked whale
Restoration of the Permian amphibian Zatrachys
A living Zapus jumping mouse
Living Zonitoides arboreus land snails
Illustration of a living Ziziphus with insets detailing the anatomy of its flower, fruit, and seeds
A living Zonotrichia albicollis, or white-throated sparrow
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