|Spiny softshell turtle, Apalone spinifera|
3 recognized species, see article.
Apalone is a fairly new classification, resurrected by Meylan in 1987, assigned to North American species of the genus Trionyx, though they are still listed as Trionyx in some texts. (Trionyx now refers specifically to certain softshell species found mainly in Africa.)
Turtles of the genus Apalone exhibit marked sexual dimorphism. In carapace length, females grow to about twice the size of males. In males, the claws on the front feet are longer than those on the back feet, but in females, the claws on the back feet are longer. In males, the stout tail extends well beyond the posterior edge of the carapace, but in females, the relatively thinner tail barely reaches the edge of the carapace.
- Apalone ferox (Schneider, 1783) – Florida softshell turtle - South Carolina, Georgia, Florida, and Alabama
- Apalone mutica (Lesueur, 1827) – smooth softshell turtle - United States, east of the Rocky Mountains
- Apalone spinifera (Lesueur, 1827) – spiny softshell turtle - Canada (southern Ontario and Quebec), most of the United States, and northeastern Mexico.
- Fritz, Uwe, and Havaš, Peter. 2007. Checklist of Chelonians of the World. Dresden: Museum für Tierkunde Dresden.
- Meylan, P.A. 1987. The phylogenetic relationships of soft-shelled turtles (family Trionychidae). Bull. American Mus. Nat. Hist. 186: 1-101.
- Smith, H.M., and E.D. Brodie, Jr. 1982. Reptiles of North America: A Guide to Field Identification. New York: Golden Press. 240 pp. ISBN 0-307-13666-3. (SOFTSHELL TURTLES—family Trionychidae, p. 30).
- "Apalone ". The Reptile Database. www.reptil-database.org.
- Rafinesque, C.S. 1832. Description of two new genera of Soft Shell Turtles of North America. Atlantic Journal and Friend of Knowledge 1: 64-65. (Apalone, new genus, p. 64).
- Genus Apolone at The Reptile Database
- Tortoise.org Apalone entry
- Spiny Softshell Turtle - Apalone spinifera Species account from the Iowa Reptile and Amphibian Field Guide