Amazon toad-headed turtle
The oval, black, olive-black or dark olive-brown carapace (to 33.0 cm) is slightly broader behind the center, flattened dorsally, and smooth posteriorly. Normally there is no medial groove, but a low vertebral keel may be present in juveniles. The flared 1st vertebral is the largest and broader than long; the 5th is also flared and broader than long, and is second largest; vertebrals 2-4 are broader than long in juveniles, but become longer with growth until the 3rd and 4th may slightly longer than broad; the 4th is the smallest vertebral. The cervical scute is long and narrow. The plastron is well-developed, and has a posterior notch. Both lobes are approximately the same width; the hindlobe does not taper toward the rear. The plastral formula is fem > intergul > abd > pect >< hum > an > gul; the intergular completely separates the gulars. The adult plastron is dark brown to olive-brown with yellowish pigment along the lateral borders of the scutes and on the inguinal region of the bridge. Each ventral marginal has a yellowish blotch. The head is large and very broad, with a slightly projecting snout, and, essentially, no medial notch on upper jaw. There are two chin barbels. The upper surface of the head is covered with small to large, irregularly-shaped scales. The adult head is uniformly dark gray or olive-gray with a cream to yellow lower jaw; that of juveniles is more ornate with dark spots and dashes. The neck is darker dorsally and lighter ventrally. Limbs are uniformly dark gray to olive-gray.
Sexual dimorphism is as in Phrynops nasutus.
This species is found in the upper Amazon and Orinoco watersheds in northeastern Bolivia, Peru, eastern Colombia, southern Venezuela and northwestern Brazil.
Small streams, ponds and lakes.
Medem (1960) reported that six to eight spherical eggs are laid in a shallow nest. Hatchlings are 58-59 mm in carapace length and lighter-colored that adults. No diet data are available.
P. raniceps was removed from the synonymy of Phrynops nasutus by Bour and Pauler (1987); this species includes P. wermuthi Mertens, 1969b.
IUCN Red List Status (1996)