Chalicotheriidae

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Chalicotheriidae (from Greek chalix, "gravel" and therion, "beast") is an extinct family of herbivorous, odd-toed ungulate (perissodactyl) mammals that lived in North America, Eurasia, and Africa from the Middle Eocene to the Early Pleistocene. They are often called chalicotheres, a term which is also applied to the broader grouping of Chalicotherioidea.[4] They are noted for their unusual morphology compared to other ungulates, such as their clawed forelimbs. Members of the subfamily Chalicotheriinae developed elongate gorilla-like forelimbs that are thought to have been used to grasp vegetation.[5] They are thought to have been browsers on foliage as well as possibly bark and fruit.[4]

Chalicotheriidae
Temporal range: middle Eocene to early Pleistocene ~48.6–1.806 Ma [1]
Moropus elatus (Schizotheriinae) at the
National Museum of Natural History,
Washington, DC
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyla
Superfamily: Chalicotherioidea
Family: Chalicotheriidae
Gill, 1872[2]
Type genus
Chalicotherium
Kaup, 1833
Subfamilies

Chalicotheriinae Gill, 1872
Schizotheriinae Holland and Peterson, 1914[3]

History of discovery

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The earliest remains chalicotheres were discovered were ungual phalanges found near Eppelsheim, Germany in early 19th century. These remains were considered to belong to gigantic pangolins by Georges Cuvier in 1822 while Johann Jakob Kaup in 1833 alternatively attributed them to deinotheres. Also in 1833, Kaup described chalicothere teeth as belonging to the new genus Chalicotherium from the same locality, which he did not recognise as belonging to the same species as the ungual phalanges. Beginning in the 1930s, the Sansan deposit in southern France was excavated for fossils, yielding remains of chalicotheres. In 1837, postcranial remains from the deposit were given the name "Macrotherium" by Édouard Lartet, who like Cuvier thought the remains represented those of a giant pangolin/edentate. In 1849, Henri Marie Ducrotay de Blainville described chalicothere skull remains from Sansan as belonging to the ungulate genus Anoplotherium (an extinct even-toed ungulate now known to be unrelated to chalicotheres). It was only in 1890 that a complete chalicothere skeleton found at Sansan was described by Henri Filhol, showing the skulls/teeth and the postcranial remains belonged to the same unusual animal.[6]

Description

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Life restoration of the chalicotheriine Anisodon grande, formerly Chalicotherium grande.

Unlike modern perissodactyls, chalicotheres had clawed feet. They had, lower incisors that cropped food against a toothless pad in the upper jaw, low-crowned molar teeth, and were browsers on trees and shrubs throughout their history. They evolved in two different directions, which became separate subfamilies, the Schizotheriinae and the Chalicotheriinae.

Schizotherine chalicotheres such as Moropus had relatively equal length limbs,[7] and lived in a variety of forest, woodland, and savannah habitats in Asia, Africa, and North America. They developed long necks and skull adaptations that suggest they had long, extensible tongues to reach browse, like those of giraffes. Strong hindlimbs and an elongated pelvis suggest they could have reared upright as modern goats do, and used their front claws to pull branches within reach of the tongue. The claws were retractable, and they walked normally on the bottom of the foot. Studies of tooth wear suggest they ate leaves, twigs, fruit, and bark.

Chalicotheriines, such as Anisodon, lived only in moist, closed-canopy forests, never reached the Americas, and developed very unusual anatomy for an ungulate. Their shorter necks and horse-like heads did not show adaptations to reach high. Instead, they developed very long forelimbs with mobile shoulder joints and hooklike claws. The pelvis and hindlimbs were specialized to stand upright, and to sit for hours while feeding, like the living gelada monkey. Some early paleontologists thought the claws were used to dig up roots and tubers, but their teeth were designed for soft foods, and studies of tooth wear show they ate fruit and seeds. Their forelimbs were specialized to reach, grasp, and strip or sweep plants to the mouth.[8] They could not retract the huge front claws, and knuckle-walked on their forelimbs. The chalicotheriines' anatomical design, posture, and locomotion show convergence with other large browsers that feed selectively in a bipedal position, such as the ground sloths, gorillas, and giant pandas.[9]

Chalicothere fossils are uncommon even in areas where other taxa of similar size are well-preserved, which suggests they were mostly solitary animals, and unlike horses, rhinos, and brontotheres, never evolved species that lived in herds. Only two species of chalicothere are known from complete skeletons, the schizotheriine Moropus from the early Miocene of North America, and the chalicotheriine Anisodon from the middle Miocene of Europe. Fossils of other species range from very fragmentary to moderately complete. Chalicotheres ranged in size from an antelope to a large draft horse.[10]

Evolution

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Chalicotheres are part of the order Perissodactyla, which includes modern equines, rhinoceroses, and tapirs, as well as extinct relatives like brontotheres.[11] As the early evolution of perissodactyls is still unresolved, their closest relatives among other perissodactyl groups is obscure.[12] They are generally placed as part of the clade Ancylopoda alongside their close relatives Lophiodontidae. Many studies considered them as closer to Ceratomorpha (which includes tapirs and rhinoceroses) than Equoidea.[13][14] A 2004 cladistic study alternatively recovered Ancylopoda as sister to all modern perissodactyls (which includes Equoidea and Ceratomorpha), with the brontotheres as the most distantly related within the order Perissodactyla.[15]

Chalicotheres can be first identified with certainty around 46 million years ago, in the Eocene of Asia. The family is thought to have evolved there, but appeared in North America by the Eocene. By the late Oligocene, they had divided into schizotheriines and chalicotheriines. (Earlier chalicotheres are often referred to the family Eomoropidae; it is not yet clear whether they had claws or how the two subfamilies diverged.)[10] Both subfamilies were successful over many millions of years, and reached their greatest diversity in the Miocene. Advanced schizotheriines (Moropus) entered North America via the Bering land bridge at the Oligicene-Miocene boundary, and expanded southward into Central America.[16]

Never common animals, the chalicotheres declined from the late Neogene onwards, disappearing from North America and Europe by end of the Miocene.[17][7] The youngest chalicotheres are the chalicotheriines Hesperotherium from the Early Pleistocene of China,[18] Nestoritherium from the Early Pleistocene of Myanmar,[19] as well as the schizotheriine Ancylotherium from the Early Pleistocene of Eastern and Southern Africa,[20] also possibly known from the Early Pleistocene of China.[21]

References

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  1. ^ Zhan-Xiang, Q. I. U. (2002-12-15). "HESPEROTHERIUM - A NEW GENUS OF THE LAST CHALICOTHERES". Vertebrata PalAsiatica. 40 (4): 317. ISSN 2096-9899.
  2. ^ Gill, Theodore (1872). Arrangement of the Families of Mammals. Smithsonian Miscellaneous Collections. Vol. 230. Washington: Smithsonian. pp. 8, 71, 76.
  3. ^ Coombs, Margery C. (13 February 2009). "The chalicothere Metaschizotherium bavaricum (Perissodactyla, Chalicotheriidae, Schizotheriinae) from the Miocene (MN5) Lagerstatte of Sandelzhausen (Germany): description, comparison, and paleoecological significance" (PDF). Paläontologische Zeitschrift. 83 (1). Berlin / Heidelberg: Springer: 85–129. Bibcode:2009PalZ...83...85C. doi:10.1007/s12542-009-0004-x. S2CID 140194075.
  4. ^ a b Semprebon, Gina M.; Sise, Paul J.; Coombs, Margery C. (March 2011). "Potential Bark and Fruit Browsing as Revealed by Stereomicrowear Analysis of the Peculiar Clawed Herbivores Known as Chalicotheres (Perissodactyla, Chalicotherioidea)". Journal of Mammalian Evolution. 18 (1): 33–55. doi:10.1007/s10914-010-9149-3. ISSN 1064-7554. S2CID 2323516.
  5. ^ Tsoukala, Evangelia (2022), Vlachos, Evangelos (ed.), "The Fossil Record of Chalicotheres (Mammalia: Perissodactyla: Chalicotheriidae) in Greece", Fossil Vertebrates of Greece Vol. 2, Cham: Springer International Publishing, pp. 501–517, doi:10.1007/978-3-030-68442-6_15, ISBN 978-3-030-68441-9, S2CID 239830368, retrieved 2023-08-06
  6. ^ Anquetin, JéRéMy; Antoine, Pierre-Olivier; Tassy, Pascal (November 2007). "Middle Miocene Chalicotheriinae (Mammalia, Perissodactyla) from France, with a discussion on chalicotheriine phylogeny". Zoological Journal of the Linnean Society. 151 (3): 577–608. doi:10.1111/j.1096-3642.2007.00327.x. ISSN 1096-3642.
  7. ^ a b Kampouridis, Panagiotis; Hartung, Josephina; Lechner, Thomas S.; Kargopoulos, Nikolaos; Böhme, Madelaine (June 2024). "Disparate occurrences of a chalicotheriine and a schizotheriine chalicothere (Mammalia, Chalicotheriidae) at the Late Miocene hominid locality Hammerschmiede (Germany)". PalZ. 98 (2): 313–329. Bibcode:2024PalZ...98..313K. doi:10.1007/s12542-024-00685-x. ISSN 0031-0220.
  8. ^ Coombs, Margery Chalifoux (1983). "Large Mammalian Clawed Herbivores: A Comparative Study". Transactions of the American Philosophical Society. 73 (7): 1–96. doi:10.2307/3137420. ISSN 0065-9746. JSTOR 3137420.
  9. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. p. 260. ISBN 1-84028-152-9.
  10. ^ a b COOMBS, MARGERY C. (2013). "A Juvenile Mandible with Deciduous Teeth of Ancylotherium Pentelicum (Perissodactyla, Chalicotheriidae, Schizotheriinae), Collected by Barnum Brown from the Late Miocene of Samos (Greece)". Journal of Vertebrate Paleontology. 33 (1): 233–238. Bibcode:2013JVPal..33..233C. doi:10.1080/02724634.2012.710281. ISSN 0272-4634. JSTOR 23361086. S2CID 85723812.
  11. ^ Savage, RJG; Long, MR (1986). Mammal Evolution: an illustrated guide. New York: Facts on File. pp. 198–199. ISBN 0-8160-1194-X.
  12. ^ Holbrook, Luke T.; Lucas, Spencer G.; Emry, Robert J. (2004). "Skulls of the Eocene Perissodactyls (Mammalia) "Homogalax" and "Isectolophus"". Journal of Vertebrate Paleontology. 24 (4): 951–956. doi:10.1671/0272-4634(2004)024[0951:SOTEPM]2.0.CO;2. ISSN 0272-4634. JSTOR 4524789. S2CID 86289060.
  13. ^ Froehlich, David J. (1999). "Phylogenetic Systematics of Basal Perissodactyls". Journal of Vertebrate Paleontology. 19 (1): 140–159. Bibcode:1999JVPal..19..140F. doi:10.1080/02724634.1999.10011129. ISSN 0272-4634. JSTOR 4523976.
  14. ^ Tsoukala, Evangelia (2022), Vlachos, Evangelos (ed.), "The Fossil Record of Chalicotheres (Mammalia: Perissodactyla: Chalicotheriidae) in Greece", Fossil Vertebrates of Greece Vol. 2, Cham: Springer International Publishing, pp. 501–517, doi:10.1007/978-3-030-68442-6_15, ISBN 978-3-030-68441-9, retrieved 2024-08-22
  15. ^ Hooker, J. J.; Dashzeveg, D. (2004). "The origin of chalicotheres (Perissodactyla, Mammalia)". Palaeontology. 47 (6): 1363–1386. Bibcode:2004Palgy..47.1363H. doi:10.1111/j.0031-0239.2004.00421.x. ISSN 1475-4983. S2CID 83720739.
  16. ^ COOMBS, MARGERY C.; HUNT, ROBERT M. (2015). "New Material of Moropus (Perissodactyla, Chalicotheriidae, Schizotheriinae) from the Early Hemingfordian Rose Creek Member of the John Day Formation, Oregon, U.s.a." Journal of Vertebrate Paleontology. 35 (6): e1009992. Bibcode:2015JVPal..35E9992C. doi:10.1080/02724634.2015.1009992. ISSN 0272-4634. JSTOR 24740217. S2CID 129074972.
  17. ^ Wood, Aaron R.; Ridgwell, Nicole M. (2015-05-04). "The first Central American chalicothere (Mammalia, Perissodactyla) and the paleobiogeographic implications for small-bodied schizotheriines". Journal of Vertebrate Paleontology. 35 (3): e923893. Bibcode:2015JVPal..35E3893W. doi:10.1080/02724634.2014.923893. ISSN 0272-4634.
  18. ^ Tong, HaoWen (September 2007). "Occurrences of warm-adapted mammals in north China over the Quaternary Period and their paleo-environmental significance". Science in China Series D: Earth Sciences. 50 (9): 1327–1340. Bibcode:2007ScChD..50.1327T. doi:10.1007/s11430-007-0096-7. ISSN 1006-9313.
  19. ^ T. Tsubamoto, Zin-Maung-Maung-Thein, Thaung-Htike, N. Egi, Chit-Sein, Maung-Maung, M. Takai Discovery of chalicothere and Dorcabune from the upper part (lower Pleistocene) of the Irrawaddy Formation, Myanmar Asian Paleoprimatology, 4 (2006), pp. 137-142
  20. ^ Handa, Naoto; Nakatsukasa, Masato; Kunimatsu, Yutaka; Tsubamoto, Takehisa; Nakaya, Hideo (2021-12-02). "The Chalicotheriidae (Mammalia, Perissodactyla) from the upper Miocene Nakali Formation, Kenya". Historical Biology. 33 (12): 3522–3529. Bibcode:2021HBio...33.3522H. doi:10.1080/08912963.2021.1876042. ISSN 0891-2963.
  21. ^ Chen, Shao-kun; Deng, Tao; Pang, Li-bo; He, Wen; Chen, Shan-qin (November 2012). "A juvenile skull of Ancylotherium (Mammalia, Perissodactyla, Chalicotheriidae) from the Pliocene of China". Geobios. 45 (6): 527–534. Bibcode:2012Geobi..45..527C. doi:10.1016/j.geobios.2012.06.002.
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