Macrochelys

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. These turtles are easily recognized by three distinct dorsal ridges with raised spikes.

== Extant species == thumb|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: 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. The two species are estimated to have diverged less than 3.5 million years ago. Macrochelys suwanniensis Thomas et al., 2014 – Suwannee snapping turtle Macrochelys temminckii (Troost, 1835) – alligator snapping turtle