The Alligator snapping turtle (Macrochelys temminckii), long thought to be a single species, is actually three species, according to a new study published in the journal Zootaxa (abstract in .pdf).
The Alligator snapping turtle, Macrochelys temminckii, in the Oasis Park, Canary Islands. Image credit: Norbert Nagel, Mörfelden-Walldorf, Germany / CC BY-SA 3.0.
The Alligator snapping turtle is the largest freshwater turtle in the world based on weight. Adult males measure up to 80 cm long and weigh up to 90 kg. There is an unverified legend that a 183-kg specimen was found in the Neosho River in Kansas in 1937.
These turtles have powerful jaws, very large heads, strongly hooked beaks and long tails. They are unique among snapping turtles for having eyes on the side of their heads.
Alligator snapping turtles are found in freshwater areas in the United States: from northern Florida to southern Georgia, through the Gulf states into Texas, and as far north as Illinois and Kansas.
Their diet includes nuts, berries, other vegetation, and any animal prey found in the water including snakes, other turtles, fish, and even small alligators.
Once heavily hunted for turtle meat – alligator snapper was the main ingredient of Campbell’s Turtle Soup in the 1960s – their river populations have been deeply depleted and are of conservation concern. The new discovery indicates that these animals are more imperiled than previously understood.
Examining museum specimens and field-captured individuals of the Alligator snapping turtle, biologists led by Dr Kevin Enge of Florida’s Fish and Wildlife Research Institute and Dr Joe Roman from the University of Vermont have discovered that the turtle is not one species, but three.
The Alligator snapping turtle, Macrochelys temminckii. Hand-colored lithograph by John Edwards Holbrook, 1842.
The two new species, scientifically named Macrochelys apalachicolae and Macrochelys suwanniensis, live in the southeastern United States.
Macrochelys suwanniensis (common name – the Suwannee alligator snapping turtle) lives only in the Suwannee River in Florida and Georgia. The most recent common ancestor of this species and the ancestor of Macrochelys temminckii-Macrochelys apalachicolae lived 5.5-13.4 million years ago, during mid-Miocene to early Pliocene.
Macrochelys apalachicolae (common name – the Apalachicola alligator snapping turtle) lives in Florida, Georgia, and Alabama – in and around the Apalachicola River. The most recent common ancestor of this species and Macrochelys temminckii existed 3.2-8.9 million years ago, during the late Miocene to late Pliocene.
“These turtles do not move from river to river; they’re isolated and have been for millions of years, through many glacial ages,” Dr Roman explained.
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Thomas TM et al. 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; doi: 10.11646/zootaxa.3786.2.4
