Gopherus

Gopherus is a genus of fossorial tortoises commonly referred to as gopher tortoises. The gopher tortoise is grouped with land tortoises that originated 60 million years ago, in North America. A genetic study has shown that their closest relatives are in the Asian genus Manouria.[1] The gopher tortoises live in the southern United States from California's Mojave Desert across to Florida, and in parts of northern Mexico. Gopher tortoises are so named because of their ability to dig large, deep burrows; those of the gopher tortoise can be up to 40 feet (12 m) in length and 10 feet (3.0 m) in depth.[2] These burrows are used by a variety of other species, including mammals, other reptiles, amphibians, and birds.[3] Gopher tortoises are 20–50 cm (7.9–19.7 in) in length, depending on the species.[4] All six species are found in xeric habitats. Numerous extinct species are known, the oldest dating to the Priabonian stage of the Late Eocene of the United States.[5]

Gopherus
Temporal range: Priabonian–Recent
Gopherus polyphemus Tomfriedel.jpg
Gopher tortoise, Gopherus polyphemus
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Superfamily: Testudinoidea
Family: Testudinidae
Genus: Gopherus
Rafinesque, 1832
Species
  • G. agassizii (Cooper, 1863)
  • G. berlandieri (Agassiz, 1857)
  • G. evgoodei Edwards et al., 2016
  • G. flavomarginatus Legler, 1959
  • G. morafkai Murphy et al., 2011
  • G. polyphemus (Daudin, 1802)

DietEdit

Gopher tortoises are mainly herbivores that feed on low growing plant life. Their diet consists mostly of grasses and legumes. Gopher tortoises are scavengers and will also feed on small berries, fruits, carrion, and excrement. Gopher tortoises are rarely seen drinking from still water. Most of the water gopher tortoises consume comes from within the food they eat.

 
Desert tortoise (Gopherus agassizii) San Bernardino County, California, US.

BreedingEdit

Gopher tortoises usually mate during April and May. The female will then choose either a sunny spot nearby or a sandy mound in front of her burrow to lay between 3 and 15 eggs. The eggs then hatch from 70 to 100 days later. Once hatched, the baby tortoises spend most of their time in their mother's burrow until they learn to dig their own burrow. They do not reach maturity until they are around 10 to 15 years old. Gopher tortoises have an abbreviated mating season in early spring, when male tortoises visit the female tortoise' burrows and mate with them.[6]

SpeciesEdit

In July 2011, researchers decided on the basis of DNA, and morphological and behavioral data that the Sonoran and Mojave populations of the desert tortoise, G. agassizii were distinct species.[7] This newly described species was named G. morafkai, or the Morafka's desert tortoise. The acceptance of G. morafkai reduced the range of G. agassizii by about 70%[8] In 2016, based on a large-scale genetic analysis, ecological and morphological data, researchers proposed a split between the Sonoran and Sinaloan populations.[9] This southernmost member of the Gopherus genus was named G. evgoodei.[9] As such, there are currently six recognized species in the genus Gopherus:

ExtantEdit

Listed alphabetically by binomial name:[10]

Image Common Name Scientific name Distribution
  Mojave desert tortoise or Agassiz's desert tortoise Gopherus agassizii (Cooper, 1863) the Mojave and Sonoran Deserts of the southwestern United States and northwestern Mexico and the Sinaloan thornscrub of northwestern Mexico
  Texas tortoise Gopherus berlandieri (Agassiz, 1857) southern Texas southward into the Mexican states of Coahuila, Nuevo León, and Tamaulipas.
  Sinaloan desert tortoise or Goode's desert tortoise Gopherus evgoodei Edwards et al., 2016[9] Mexico (Sonora, Sinaloa)
  Bolson tortoise Gopherus flavomarginatus Legler, 1959 north-central Mexico
  Sonoran desert tortoise or Morafka's desert tortoise Gopherus morafkai Murphy et al., 2011[7] Mexico (Sonora and Sinaloa)
  Gopher tortoise Gopherus polyphemus (Daudin, 1802) southeastern United States.

FossilEdit

Members of Gopherus that became extinct in the late Pleistocene:

  • Gopherus donlaloi (Reynoso and Montellano-Ballesteros, 2004)[11][12][13]
  • Gopherus depressus[14]

ConservationEdit

 
Texas tortoise (Gopherus berlandieri), northern Tamaulipas, Mexico

Populations of all six species of Gopherus have declined dramatically. In the past, gopher tortoises were hunted for their meat, which was used in stews.[15] Currently the most significant threat to their survival is habitat destruction, but the pet trade and collisions with vehicles have also taken their toll.[4] To help decrease gopher tortoise death due to collisions with vehicles, the US Department of Transportation in Mississippi has recently placed angled fences along the road side to keep tortoise from wandering onto the highways near their habitats.[16] On November 9, 2009, the US Fish and Wildlife Service proposed rulemaking to include the eastern population of the gopher tortoise, Gopherus polyphemus, in the List of Threatened Wildlife.[17] In 2018, the IUCN Tortoise and Freshwater Turtle Specialist Group recommended a re-assessment and re-classification of all six Gopherus species[18] This reclassification would move G. agassizii from Vulnerable (VU) to Critically Endangered (CR), G. berlandieri from Near Endangered (NE) to Near Threatened (NT), G. evgoodei from Near Endangered (NE) to Vulnerable (VU), G. flavomarginatus from Vulnerable (VU) to Critically Endangered (CR), G. morafkai from Near Endangered (NE) to Vulnerable (VU) and G. polyphemus from Vulnerable (VU) to Endangered (EN).[18]

ReferencesEdit

  1. ^ Le, M.; Raxworthy, C. J.; McCord, W. P.; Mertz, L. (2006-05-05). "A molecular phylogeny of tortoises (Testudines: Testudinidae) based on mitochondrial and nuclear genes". Molecular Phylogenetics and Evolution. 40 (2): 517–531. doi:10.1016/j.ympev.2006.03.003. PMID 16678445.
  2. ^ "About The Gopher tortoise". Gopher Tortoise Council. Archived from the original on 2009-09-01. Retrieved 2009-07-03.
  3. ^ Fergus, Charles (2007). Turtles. Stackpole Books. pp. 22–24. ISBN 978-0-8117-3420-2.
  4. ^ a b Franklin, Carl J. (2007). Turtles: An Extraordinary Natural History 245 Million Years in the Making. MBI Publishing Company. pp. 129–131. ISBN 978-0-7603-2981-8.
  5. ^ "Fossilworks: Gopherus". fossilworks.org. Retrieved 2020-02-29.
  6. ^ Landers, L. J.; Garner, J. A. & McRae, W. A. (1980). "Reproduction on Gopher Tortoises in Southwestern Georgia". Herpetological. 36: 353–361.
  7. ^ a b US Geological Survey
  8. ^ Murphy, Robert; Berry, Kristin; Edwards, Taylor; Leviton, Alan; Lathrop, Amy; Riedle, J. Daren (2011-06-28). "The dazed and confused identity of Agassiz's land tortoise, Gopherus agassizii (Testudines: Testudinidae) with the description of a new species and its consequences for conservation". ZooKeys. 113: 39–71. doi:10.3897/zookeys.113.1353. ISSN 1313-2970. PMC 3187627. PMID 21976992.
  9. ^ a b c Edwards T, Karl AE, Vaughn M, Rosen PC, Torres CM, Murphy RW (2016). "The desert tortoise trichotomy: Mexico hosts a third, new sister-species of tortoise in the Gopherus morafkaiG. agassizii group". ZooKeys (562): 131–158. doi:10.3897/zookeys.562.6124. PMC 4768471. PMID 27006625.
  10. ^ Gopherus, The Reptile Database
  11. ^ Reynoso, Víctor-Hugo; Montellano-Ballesteros, Marisol (2004-01-01). "A New Giant Turtle of the Genus Gopherus (Chelonia: Testudinidae) from the Pleistocene of Tamaulipas, México, and a Review of the Phylogeny and Biogeography of Gopher Tortoises". Journal of Vertebrate Paleontology. 24 (4): 822–837. doi:10.1671/0272-4634(2004)024[0822:angtot]2.0.co;2. JSTOR 4524778.
  12. ^ Rostal, David C.; McCoy, Earl D.; Mushinsky, Henry R. (2014-06-13). Biology and Conservation of North American Tortoises. JHU Press. ISBN 9781421413778.
  13. ^ "Ecological history and latent conservation potential: large and giant tortoises as a model for taxon substitutions" (PDF).
  14. ^ Woodburne & Golz, 1972
  15. ^ "Gopher Tortoise Stew", in: Recipes from Another Time: Savor the flavor of old St. Augustine and try a couple of these original recipes. Smithsonian magazine, October 2001
  16. ^ "Fence with an "angle" protects gopher tortoises". US Department of Transportation. 2003-04-25. Retrieved 2010-04-18.
  17. ^ "Federal Register, 50 CFR Part 17" (PDF). 74 (215). National Archives and Records Administration. 2009-11-09. Retrieved 2009-11-13. Cite journal requires |journal= (help)
  18. ^ a b Rhodin, Anders G. J.; Stanford, Craig B.; Dijk, Peter Paul Van; Eisemberg, Carla; Luiselli, Luca; Mittermeier, Russell A.; Hudson, Rick; Horne, Brian D.; Goode, Eric V.; Kuchling, Gerald; Walde, Andrew (December 2018). "Global Conservation Status of Turtles and Tortoises (Order Testudines)". Chelonian Conservation and Biology. 17 (2): 135–161. doi:10.2744/CCB-1348.1. ISSN 1071-8443.

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