Rhinoclemmys melanosterna

(Gray, 1861)
Colombian wood turtle

This is a large (to 29 cm) aquatic turtle with an oval, somewhat domed, black to dark-brown carapace widest at the level of marginals 6-7, highest at the level of anterior vertebral 3, and notched posteriorly. A medial keel is usually present, and the carapacial surface may be slightly rugose. The well-developed plastron is upturned anteriorly and notched posteriorly, and has a scute formula of abd > pect > fem > an > gul > hum. It is red brown to black with a yellow border and midseam. The head is small with a slightly projecting snout and a medially notched upper jaw. It is dark brown to black with a dorsal pattern consisting of an oblique pale-green to orange or red stripe on each side running posteriorly from in front of the orbit to above the tympanum and there curving downward toward the posterior side of the tympanum. No light blotches occur on the snout in front of these stripes or on the nape, and the oblique stripes are never united across the forehead. The iris is yellow or bright white. The forelimbs are black spotted, and the toes webbed.
Males are smaller (to 25 cm), have flatter carapaces, slightly concave plastra, and longer, thicker tails with the vent beyond the carapacial rim.

Rhinoclemmys melanosterna lives in the Caribbean drainages of southeastern Panama and northern Colombia, and Pacific drainages of western Colombia and northwestern Ecuador.

Geographic Variation
No subspecies are recognized; however, Medem (1962; pers. comm., 1974) remarked that those living in a freshwater habitat always had red head stripes, whereas those from brackish waters close to the Pacific Coast of Colombia had green to greenish yellow stripes. Populations intermediate (intergrade?) between the two possessed orange stripes. There were no morphological differences, although red-striped turtles seemed to be larger. Field study is needed to verify this, since the pigmentation of the head stripes disappears during preservation.

Rhinoclemmys melanosterna occupies a variety of aquatic sites from ponds and marshes to lakes and large rivers in savannahs to deep rainforests. It also enters brackish coastal waters.

Natural History
Medem (1962) and CastaƱo-Mora and Medem (1983) reported that nesting occurs throughout the year, but principally in June-August and November. One or two (exceptionally three) ellipsoidal (48-71 x 28-38 mm) eggs form a clutch. No cavity is dug; instead the eggs are covered with rotting leaves. The eggs hatch in 85-141 days, principally in September-November. Hatchlings have carapace lengths of 39-59 mm.
Rhinoclemmys melanosterna is fond of basking. In the wild it is principally herbivorous, but captives will accept a variety of animal foods (Medem, 1962).

IUCN Red List Status (1996)
Not listed.