(Spix, 1824)
Red side-necked turtle
Recognition
The oval, high-peaked brown carapace (to 25.6 cm) is medially keeled and has a slightly serrated posterior rim. Its cervical scute is long and very narrow. Vertebrals are broader than long; the 1st is slightly flared anteriorly, and the 5th is distinctly expanded posteriorly. Posterior and lateral marginals are outwardly flared. The plastron is large, covering much of the carapacial opening. Its forelobe is broader than the hindlobe, and on the anterior rim the long, broad, intergular scute projects in front of the gulars. The posterior rim bears a distinct notch. The intergular scute completely separates the smaller gulars, but is shorter than its distance from the abdominal scutes. The plastral formula of the three specimens we examined was: intergul >< fem > an > hum >< pect > abd > gul. Plastron, bridge, and undersides of the marginals are cream to yellow. The head is broad and flattened with a projecting snout and an unnotched upper jaw. Behind the orbits, the sides of the head bear numerous irregularly shaped scales, but the skin on top is smooth and unbroken. Two small chin barbels are present. The head is bright red with a black stripe extending backward from each orbit to the neck and a wide medial black stripe beginning on top of the snout and running backward between the orbits to the nape. This medial stripe may be broken on the snout or between the orbits; also the two lateral stripes may pass through the orbit to join the medial stripe in front of the eye. Outer surfaces of the limbs and neck are red, but there may be extensive dark-brown or black pigment along the outer edge of the forelimbs and on the heel of the hind foot. However, all red pigment may fade with age.
Males have longer and thicker tails and concave plastra; the plastra of females are flat. Females grow larger (Lamar and Medem, 1982).
Distribution
This turtle is restricted to northwestern Brazil, adjacent southeastern Colombia and (possibly) Peru.
Habitat
Phrynops rufipes lives in flowing creeks in rainforests. It is known from both blackwater and whitewater streams and spends most of its time on the bottom foraging or hiding in the substrate of leaf debris. It seldom basks.
Natural History
Pritchard (1979) reported it nests during July and August, but Lamar and Medem (1982) stated that oviposition occurs from early June until August and from December to February at two Colombian sites. Three to 12 small, spherical (41-42 x 37-38 mm), brittle-shelled eggs are laid at one time. Hatching may occur in September; the young are light brown with a well-developed vertebral keel and a strongly serrated carapace.
Phrynops rufipes is omnivorous, eating a variety of foods: palm fruits, legumes euphorbs, vines, seeds, algae, aquatic animals (worms, aquatic insects, crabs, shrimp, fish, amphibians), earthworms, and lizards (Lamar and Medem, 1982; Cardosa de Lima et al., 1997). It seems to specialize on eating palm fruits and seeds that drop into the water.
P. rufipes does poorly in captivity as it is prone to develop bacterial or fungal infections of the skin and quickly dies.
Remark
Serological tests conducted by Frair (1982a) have shown P. rufipes to be most closely related to P. geoffroanus and P. hilarii, which supports its inclusion in the subgenus Phrynops Wagler, 1830.
IUCN Red List Status (1996)
Lower risk: near threatened.