Emydidae

The Emydidae, commonly called the pond turtles or marsh turtles, are a family of turtles. Previously, several species of Asian box turtles were classified in the family. However, revised taxonomy has separated them to a different family. Now, the Emydidae, with the exception of two species of pond turtles, are entirely a Western Hemisphere family. The family Emydidae includes close to 50 species in 10 genera.

Description

The upper shell (carapace) of most emydids is the shape of a low arch, although in some species, it is domed. The upper shell may have one or two ridges that run from front to the back of the animal (a projection commonly called a "keel"), or such a feature may be absent. A prominent bridge often connects the top shell to the bottom shell (plastron). Emydids have large bottom shells, and some members of the family have a movable hinge that separates pectoral and abdominal segments (scutes). The skull is small.

The limbs of these turtles are adapted for swimming, with every member having some level of toe webbing.