The elongated, domed carapace (to 40.3 cm) has a wide transverse bar on the second pleural; it is highest at the center and widest behind the center, with a slightly serrated posterior rim. Vertebral 1 may be longer than broad or as long as broad, vertebrals 2-5 are broader than long. The carapace is brown to olive-black with yellow markings. The wide yellow bar on the second pleural may be forked at the upper or lower end or both. Other pleural and vertebral light marks are reticulate. The upper surface of each marginal has a central yellow bar. The hingeless plastron and bridge are yellow and usually devoid of dark pigment. The ventral side of the anterior marginals to the bridge has a dark, usually solid but sometimes yellow centered, spot covering the posterior seam. The plastral hindlobe is posteriorly notched, and the plastral formula is: abd > an > fem >< pect > gul > hum. The head is of moderate size with a slightly projecting snout and no medial notch or cusps on the upper jaw. Sides of the jaws are smooth to only weakly serrated. Skin is usually black with yellow or cream stripes. The supratemporal and paramedian stripes unite on the side of the head behind the eye, forming a "hairpin-like" pattern. Usually no postorbital stripe is present between the orbit and tympanum. Ventrally, the neck is marked with wide yellow stripes, and a central chin stripe extends backward and divides to form a Y-shaped mark.
Males have elongated foreclaws and long, thick tails, with the vent behind the carapacial rim. Males are flatter and also slightly smaller than females.
Pseudemys peninsularis ranges from Levy, Alachua, Putnam, and St. Johns counties southward through peninsular Florida (Ashton and Ashton, 1985; Iverson and Etchberger, 1989).
Principally, this species is found in slow moving waters with soft bottoms, ample aquatic vegetation, and abundant basking sites, such as wet prairies, large swamps, lakes, sloughs and canals, but it is also found in the deeper, clear springs, streams and rivers of peninsular Florida.
Reproductive activity may occur throughout the year (the species does not hibernate). The Peninsula cooter produces clutches throughout the year, but particularly in late fall, winter, or early spring (Jackson, 1988). The nest cavity is roughly flask-shaped and is dug with the hind feet in friable soil in open places. Usually one or more additional cavities, ordinarily containing 1-2 eggs, are dug 5.0-7.5 cm from the main nest chamber (Iverson, 1977d; Jackson, 1988).
A clutch usually has about 20 eggs, but clutches of 10-29 eggs are known. The elliptical eggs are white, and have calcified, parchmentlike shells with a coarse granular surface. Variable in size, they average 25 mm (20-27) in width and 34 mm (29.0-40.5) in length. Natural incubation lasts 80-150 days, depending on soil temperature. The 24-27 mm hatchlings are more bright than adults and have a well-developed medial keel.
Adult P. peninsularis are largely herbivorous; they consume a wide variety of aquatic plants, including algae, Ceratophyllum, Egeria, Hydrilla, Lemna, Leptodictyum, Myriophyllum, Najas, Sagittaria, and Vallisneria (Ernst et al., 1994; Bjorndal et al., 1997). The young take more animal prey (particularly small fish and aquatic insects), but become less carnivorous as they grow older.
This turtle was only recently elevated to species status during a revision of the genus Pseudemys by Seidel (Seidel, 1994, 1995; Seidel and Dreslik, 1996; Seidel and Ernst, 1996; Seidel and Palmer, 1991).
IUCN Red List Status (1996)