They are typically much larger than other species of musk turtles, attaining sizes of up to 36 cm (14 in) carapace length, with males being significantly smaller than females. They are typically brown, black, or green in color, with yellow undersides. Their carapaces are distinguished by three distinct ridges, or keels, which run their length.
Wagler, J.G. 1830. Natürliches System der Amphibien, mit vorangehender Classification des Säugthiere und Vögel. Ein Beitrag zur vergleichenden Zoologie. J.G. Cotta. Munich, Stuttgart, and Tübingen. vi + 354 pp. (Genus Staurotypus, p. 137.)