Description: 4 - 5 inches. Common Musk Turtles have a dark brown to black upper shell (carapace) with no markings. The skin is dark, and the heads have two light colored lines on each side. The bottom shell (plastron) is light colored and much smaller than the upper shell, and has skin showing between the scales.

Similar Species: Yellow Mud Turtles do not have yellow markings on the side of the head, and have a larger bottom shell, and flattened upper shell. Large Snapping Turtles with smooth shells may appear similar to Common Musk Turtles in photos, but Snapping Turtles within the size range of Common Musk Turtles will have a much rougher upper shell, as well as a tail that is as long as the upper shell.