noun
also alligator turtle or alligator terrapin
1. : a voracious snapping turtle ( Macrochelys temminckii ) of the rivers of the Gulf states differing from the common snapping turtle in its larger size which in old age reaches nearly 150 pounds in weight and 5 feet in length, its scaly head, and its numerous small scales beneath the tail
2. : a snapping turtle ( Chelydra serpentina )