| Suwannee alligator snapping turtle | |
|---|---|
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Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Testudines |
| Suborder: | Cryptodira |
| Family: | Chelydridae |
| Genus: | Macrochelys |
| Species: | M. suwanniensis |
| Binomial name | |
| Macrochelys suwanniensis | |
| Synonyms | |
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TheSuwannee alligator snapping turtle (Macrochelys suwanniensis) is a largespecies ofturtle in the familyChelydridae. This species isendemic to the southeasternUnited States, where it only inhabits theSuwannee River basin.[5][6]
It is one of only two known species in the genusMacrochelys, the other being the far more widespreadalligator snapping turtle (M. temminckii); a third, theApalachicola snapping turtle (M. apalachicolae), which was described alongsideM. suwanniensis, is not thought to be distinct fromM. temminckii and has been synonymized with it. It was previously believed to represent a population ofMacrochelys temminckii, but a 2014 study found significant genetic divergence between the Suwannee population andM. temminckii, dating back to the lateMiocene to earlyPliocene, about 5.5 to 13.4 million years ago, and thus the Suwannee population was described as a distinct species,M. suwanniensis.[7]
This species is only found in theSuwannee River basin, in southernGeorgia and northern portions of peninsularFlorida; it isallopatric with respect toM. temminckii, which inhabits river basins further to the west. It inhabits onlyriparian habitats such as rivers and their tributaries, but sometimes utilizesbackwaterswamps andoxbow lakes. Individuals found in inland lakes have likely been introduced.[8] In 2021, an individual was discovered within theOkefenokee Swamp, indicating that a previously-undocumented population of these turtles may inhabit the swamp.[9] Approximately 2,000 Suwanee alligator snapping turtles are believed to remain in the wild as of 2022, and the species still occupies much of its known historical range.[3]
This species appears to exhibitsexual dimorphism, with males tending to be larger than females. In samples from six distinct ecological reaches running downstream betweenWhite Springs and Suwannee Estuary, mature females were found to have a straight-midlinecarapace length between 351-550 mm, while mature males had a straight-midlinecarapace length between 451-650 mm. Males found had an average straight-midline carapace of 552 ± 7.1 mm, carapace width of 458 ± 5.2 mm,plastron length of 400 ± 4.2 mm, head width of 177 ± 2.3 mm, tail length of 330 ± 4.1 mm, and mass of 38.0 ± 1.2 kg. In comparison, females had an average straight-midline carapace of 416 ± 7.5 mm, carapace width of 358 ± 6.7 mm,plastron length of 313 ± 6.3 mm, head width of 134 ± 3.7 mm, tail length of 292 ± 6.6 mm, and mass of 16.6 ± 0.8 kg. Environment appears to play a large role in size determination, as each ecological reach has various implications on average size and mass.[10]
Due to its slowgeneration time, the Suwanee alligator snapping turtle is highly vulnerable to direct stressors such asturtle hunting (illegal in Florida) and indirect stressors such ashabitat destruction.[11] They are additionally at risk from ingesting discarded fishing tackle, baited hooks left ontrotlines and from capture of juveniles in abandoned hoop nets used for baitfish or catfish fishing.[3][12] They may experience mortality asbycatch during recreational and commercial freshwater fishing.[3] In 2021, theU.S. Fish and Wildlife Service proposed listing the species under theEndangered Species Act of 1973.[11][12][13] Effective July 29, 2024, the species gained protection as a threatened species under the Endangered Species Act.[3][14]
