Turtle, Big-headed or Gibba


Mesoclemmys gibba


The ellipsoidal, slightly bowed carapace (to 23.3 cm) has a medial keel, is somewhat serrated, has a shallow supracaudal notch. Its surface is smooth or slightly roughened. Vertebraes are broader than long and the 3rd to 5th may bear a small posterior projection on a low keel. Neural bones vary from none to five, but, if present, they are rudimentary and never contact the nuchal (Pritchard and Trebbau, 1984). The carapace is chestnut brown to dark gray or black. The plastron is well-developed and slightly upturned anteriorly. Its intergular scute completely separates the gulars, but not the humerals, and is shorter than its distance from the abdominals. The posterior plastral lobe curves inward and the anals are deeply notched posteriorly. The plastron is red brown to yellow with a brown blotch on each scute, and a narrow yellow border may occur anteriorly and posteriorly. Bridge and undersides of the marginals are brown to yellow. Together, the head and neck are considerably shorter than the carapace. Dorsally and laterally, the head is covered with numerous convex scales; those between the orbit and tympanum are smaller than those on the top and sides of the head. The snout protrudes and the upper jaw is not notched or serrated. Head and neck are red brown to dark gray dorso-laterally and grayish to pale yellow ventrally; the jaw may contain dark spots and the two small chin barbels are yellow. The upper jaw is often yellow to white with black bars. The toes are heavily webbed and there is a fringe of large scales on the outer border of the forelimbs and hindlimbs. Limbs and tail are gray black, limb sockets yellow.

Family

Chelidae

Order

Testudines

Class

Reptilia

Range

C & NE Peru, E Ecuador, SE Colombia, SW/NE Venezuela (Sierra Nevada de Mérida), Trinidad, Guyana, Surinam, Paraguay, and Brazil (Roraima)

Habitat

Shallow marshes, pools and ponds, streams, and blackwater rivers usually located under the tree canopy of primary forests.

Life Expectancy

Unknown in the wild; 6 – 8 years in captivity

Sexual Maturity

Unknown

Diet

In the wild, they eat plants, aquatic insect larvae and tadpoles; in the Zoo, they are fed fish and aquatic plants.

Status

Not Listed

Behaviors

Gibba turtles are shy and basically nocturnal, although some bask in the daytime. When first captured they emit a foul-smelling musk and often bite. The nesting period extends from July to November. Usually two to four elongated, white, hard-shelled eggs are laid in a cavity about 10 cm deep. Some females, however, lay their eggs on the surface of the ground in leaf litter or among roots. Incubation may last up to 200 days. The 45-48 mm hatchlings range in carapacial coloration from totally black to cream with black flecks.

Adaptions

This is a highly aquatic species with webbed feet and the capacity to stay submerged for long periods of time.

Special Interests

It is also known by the scientific name Phrynops gibbus. The Chelidae are one of the three living families of the turtle suborder Pleurodira and are commonly called the Austro-South American Side Neck turtles. It is a large family of turtles with a significant fossil history going back to the Cretaceous. The family is entirely Gondwanan in its origin with no members found outside of Gondwana, either in the present day or as a fossil.

Folklore

Conservation

Jacksonville Zoo History

The gibba turtle was first found on the Jacksonville Zoo’s animal inventory in 2010.

Exhibit

Range of the Jaguar