Pseudemys nelsoni

Carr, 1938c
Florida red-bellied turtle

Pseudemys nelsoni has a high-arched, elongated carapace (to 34 cm) with the highest point usually anterior to the middle, the widest point at the middle, and the posterior rim slightly serrated. The medial keel is lost in adults. Vertebral 1 is longer than broad or as long as broad; vertebrals 2-5 are broader than long. The carapace is variable in color but usually black, with red or yellow markings on the pleurals and marginals. The 2nd pleural has a light, central band, which passes dorsoventrally and, just below the dorsal edge, usually bends sharply toward the rear and passes to the upper rear edge of the pleural; often this band is branched, forming a Y-shaped figure. Each marginal has a red bar located centrally on its dorsal surface; the ventral surface exhibits dark smudgelike blotches at the seams. Melanism may occur in older individuals of either sex. The bridge is usually immaculate, but sometimes bears dark blotches. The plastron is reddish orange and may be plain or carry a medial pattern which fades with age. Its hindlobe is only slightly posteriorly notched, and the plastral formula is: abd > an > pect >< fem > gul > hum. The head is moderate with a nonprotruding snout and a prominent notch at the tip of the upper jaw, often with a toothlike cusp on each side. Skin is black with yellow stripes, and there is a prefrontal arrow. One to three stripes occur between the supratemporals behind the eyes, and the paramedial head stripes usually are reduced and always end behind the eyes.
The diploid chromosome number is 50: 26 macrochromosomes (16 metacentric, 6 submetacentric, and 4 telocentric) and 24 microchromosomes (Killebrew, 1977a).
Males have elongated, slightly curved foreclaws and long, thick tails, with the vent posterior to the carapacial rim. Females are slightly larger than males.

Pseudemys nelsoni ranges from the Okefenokee Swamp in southern Georgia west to Apalachicola, Florida, and south through peninsular Florida.

Geographic Variation
No subspecies are recognized, but hybridization with P. concinna may occur.

This turtle has been taken from ponds, lakes, ditches, sloughs, marshes, mangrove-bordered creeks, and slow-flowing rivers. Water containing abundant aquatic vegetation is preferred.

Natural History
Males mature at plastron lengths of 17-21 cm in 3-4 years; females mature at plastron lengths of 26-27 cm in 5-7 years (Jackson, 1988). Courtship and mating have been observed from October to March, but possibly occur throughout the year. During courtship the male trails the female, and smells her thighs and cloacal area. If she flees, he follows with head and neck extended, nuzzling her hindquarters. He may swim around to her side, stretching his neck fully then bending it to bring his head close to her face and touching her with his nose. He then rapidly strokes the sides of her face with his foreclaws. Following this, he may bite her neck. Finally, he moves backward and grasps her carapace in the inguinal region with his foreclaws. She elevates her tail, and he inserts his penis into her cloacal vent (Lardie, 1973; Kramer and Fritz, 1989).
Mating apparently occurs throughout the year, and 3-6 separate clutches of 6-31 eggs may be laid each year. A favorite nesting site is an alligator's nest of decaying vegetation. The elliptical, parchment-shelled eggs (37-47 x 19-26 mm) probably hatch after 60-75 days. At times the nest site is flooded. If the eggs are submerged for only a short period, this may facilitate embryogenesis, but, if the period of submergence is too long, hatching success may be drastically diminished depending on how long the eggs are underwater (Kam, 1994).
Hatchlings are brighter than adults, and the carapace (28-32 mm) is rounded and slightly keeled. The plastron is orange or red, and the dark plastral markings are solid semicircles with the flat sides along the seams.
Adult P. nelsoni are highly herbivorous; the young, like those of other species of Pseudemys, probably are more carnivorous, feeding on aquatic insects and other small invertebrates. Adults prefer Cicuta, Egeria, Hydrilla, Eichhornia, Sagittaria, Lemna, Mikania, Najas, Vallesneria, and algae, but have scavenging tendencies and will eat carrion, such as dead fish (Ernst et al., 1994; Bjorndal et al., 1997). A Florida red-bellied turtle feeding on Hydrilla has high digestive efficiencies for dry matter (80%), organic matter (81%), energy (75%), and cell walls (86%), and moderate digestive efficiency for nitrogen (58%) (Bjorndal and Bolten, 1990). Microbial fermentation occurs in the intestines and is responsible for the high cell wall digestibility. Apparently hatchlings can process foods faster than adults (Bjorndal and Bolten, 1992). Captive adults eat fish, various meats, and lettuce.
P. nelsoni is a confirmed basker, lying many hours each sunny day on logs or floating mats of vegetation. They are not very wary, and can often be approached quite close.

IUCN Red List Status (1996)
Not listed.