Macrochelys

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Macrochelys
Temporal range: Miocene–Recent
Alligator snapping turtle.jpg
Alligator snapping turtle (Macrochelys temminckii)
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Testudines
Suborder: Cryptodira
Family: Chelydridae
Genus: Macrochelys
Gray, 1856 [1]
Type species
Macrochelys temminckii
Troost, 1835

Macrochelys is a genus of very large freshwater turtles in the family Chelydridae, native to the Southeastern and Midwestern United States. Only a single extant species was recognized until 2014, when a study divided it into two, or possibly three species. [2] These turtles are easily recognized by three distinct dorsal ridges with raised spikes.

Contents

Extant species

Skeleton of an alligator snapping turtle (Macrochelys temminckii) on display at the Museum of Osteology Alligator Snapping Turtle Skeleton.jpg
Skeleton of an alligator snapping turtle (Macrochelys temminckii) on display at the Museum of Osteology

Traditionally, only a single extant species (M. temminckii) was recognized, but following reviews, two species are now recognized: [3] [4] Anatomical differences between the two species of Macrochelys include the shape of the caudal notch at the rear of the carapace and the angle of the squamosal bone at the rear of the skull. [5] The two species are estimated to have diverged less than 3.5 million years ago. [5]

A third species has been proposed, [5] [6] but its validity is disputed. [7] Neither the Reptile Database [3] nor IUCN's Tortoise and Freshwater Turtle Specialist Group recognize it as separate from M. temminckii. [4]

Fossil history and extinct species

Unlike the family Chelydridae as a whole, the genus Macrochelys is exclusively North American. Hutchison (2008) considered the genus Chelydrops to be a junior synonym of Macrochelys, and recombined its type species, Chelydrops stricta from the Miocene (Early Barstovian) of Nebraska, as the (then) fourth species of Macrochelys. [8]

There are two other species known only from fossil remains:

Related Research Articles

<span class="mw-page-title-main">Chelydridae</span> Family of turtles

The Chelydridae is a family of turtles that has seven extinct and two extant genera. The extant genera are the snapping turtles, Chelydra and Macrochelys. Both are endemic to the Western Hemisphere. The extinct genera are Acherontemys, Chelydrops, Chelydropsis, Emarginachelys, Macrocephalochelys, Planiplastron, and Protochelydra.

<span class="mw-page-title-main">Alligator snapping turtle</span> Large freshwater turtle from the Eastern United States

The alligator snapping turtle is a large species of turtle in the family Chelydridae. The species is native to freshwater habitats in the United States. M. temminckii is one of the heaviest freshwater turtles in the world. It is the largest freshwater species of turtle in North America. It is often associated with, but not closely related to, the common snapping turtle, which is in the genus Chelydra. The specific epithet temminckii is in honor of Dutch zoologist Coenraad Jacob Temminck.

<i>Chelydra</i> Genus of turtles

Chelydra is one of the two extant genera of the snapping turtle family, Chelydridae, the other being Macrochelys, the much larger alligator snapping turtle. The snapping turtles are native to the Americas, with Chelydra having three species, one in North America and two in Central America, one of which is also found in northwestern South America.

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<span class="mw-page-title-main">New Guinea snake-necked turtle</span> Species of turtle

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<i>Elseya</i> Genus of turtles

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<span class="mw-page-title-main">New Guinea snapping turtle</span> Species of turtle

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<i>Chelodina burrungandjii</i> Species of turtle

Chelodina (Chelydera) burrungandjii, the sandstone snake-necked turtle or Arnhem Land long-necked turtle, is a medium-sized turtle reaching carapace lengths of 316 mm. The species is found in the sandstone plateaus and escarpments and the plunge pools of Arnhem Land of the Northern Territory. The species had been long recognised as valid. However, it had been difficult to research due to the remoteness of its habitat. Efforts to breed this species in captivity had been largely unsuccessful, until National Aquarium Herpetologist Matthew Benedict lead a successful breeding project in 2021. The species occurs in proximity to Chelodina rugosa, to which it is closely related. For the most part the two species are parapatric in distribution. However, they do come together in limited locations such as plunge pools at the base of the escarpments. In these areas there is hybridization between the species.

<i>Elseya schultzei</i> Species of New Guinea turtle

Elseya schultzei, commonly known as Schultze's snapping turtle, is a species of chelid turtle endemic to northern New Guinea.

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The Turtle Taxonomy Working Group (TTWG) is an informal working group of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group (TFTSG). It is composed of a number of leading turtle taxonomists, with varying participation by individual participants over the years, some dropping out and others joining.

The Apalachicola snapping turtle is a proposed species that lives in the Apalachicola River, United States. The species can as well be found within other panhandle rivers within the states of Florida, Georgia, and Alabama. It has traditionally been included as part of the widespread species M. temminckii, but an analysis in 2014 recommended treating it as distinct. A study published the following year considered this change unwarranted and recommended that M. apalachicolae should be considered a junior synonym of M. temminckii, and this is followed by the Reptile Database, IUCN's Tortoise and Freshwater Turtle Specialist Group, and the Committee On Standard English And Scientific Names. The Apalachicola snapping turtles and other species of snapping turtle have been classified as endangered due to human activity which is causing the destruction to their natural habitats

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References

  1. Rhodin, Anders G.J.; van Dijk, Peter Paul; Inverson, John B.; Shaffer, H. Bradley; Roger, Bour (2012-12-31). "Turtles of the world, 2012 update: Annotated checklist of taxonomy, synonymy, distribution and conservation status" (PDF). Chelonian Research Monographs. 5: 000.251. doi:10.3854/crm.5.000.checklist.v5.2012. ISBN   978-0965354097. Archived from the original (PDF) on 2013-06-16.
  2. John R. Platt (April 17, 2014). "Alligator Snapping Turtles, the Dinosaurs of the Turtle World, Are Actually 3 at-Risk Species". Scientific American.
  3. 1 2 Reptile Database: Macrochelys. Retrieved 26 September 2017.
  4. 1 2 Turtle Taxonomy Working Group [Rhodin, A.G.J., Iverson, J.B., Bour, R. Fritz, U., Georges, A., Shaffer, H.B., and van Dijk, P.P.] (2017). "Turtles of the World: Annotated Checklist and Atlas of Taxonomy, Synonymy, Distribution, and Conservation Status (8th Ed.)." In: Rhodin, A.G.J., Iverson, J.B., van Dijk, P.P., Saumure, R.A., Buhlmann, K.A., Pritchard, P.C.H., and Mittermeier, R.A. (Eds.). "Conservation Biology of Freshwater Turtles and Tortoises: A Compilation Project of the IUCN/SSC Tortoise and Freshwater Turtle Specialist Group." Chelonian Research Monographs 7:1–292. doi : 10.3854/crm.7.checklist.atlas.v8.2017.
  5. 1 2 3 Thomas, T., Granatosky, M. Bourque, J., Krysko, K., Moler, P., Gamble, T., Suarez, E., Leone, E., Enge, K. & Roman, J. (2014). "Taxonomic assessment of Alligator Snapping Turtles (Chelydridae: Macrochelys), with the description of two new species from the southeastern United States." Zootaxa 3786(2): 141–165.
  6. Joshua E. Brown (April 24, 2014). "Research splits alligator snapping turtle, 'dinosaur of the turtle world,' into three species". Phys.org.
  7. Folt, B.; and C. Guyer (2015). "Evaluating recent taxonomic changes for alligator snapping turtles (Testudines: Chelydridae)." Zootaxa 3947(3): 447–450.
  8. J. Howard Hutchison (2008). "History of fossil Chelydridae". In A.C. Styermark; M.S. Finkler; R.J. Brooks (eds.). Biology of the Snapping Turtle (Chelydra serpentina). Johns Hopkins University Press. pp. 14–30.