South American yellowfooted tortoise

Geochelone denticulata

TAXONOMY

Testudo denticulata Linnaeus, 1766, Virginia. No subspecies are recognized.

OTHER COMMON NAMES

English: Morrocoy amarillo, yellow-footed tortoise. PHYSICAL CHARACTERISTICS

This is a large tortoise (up to 10 in [26 cm] carapace length) with an elongate, high-domed shell with the twelfth marginal scutes fused to form a supracaudal scute, the fifth and sixth marginal scutes touching the second pleural scutes, no nuchal scute, no carapacial or plastral hinge, a divided gular scute that does not strongly project anteriorly and does not reach the en-toplastron, a humeropectoral seam that does not cross the en-toplastron, the external narial opening basically rounded, the premaxilla lacking a medial ridge, but the maxilla bearing one, an unflattened tail that lacks an enlarged terminal scale, five claws on the forefeet, the forelegs with large yellow or orange scales, and the carapace with the older scutes areas yellow or orange.

DISTRIBUTION

Atlantic versant of northern South America, including the Amazon River basin; southern populations may be disjunct.

I Geochelone denticulata I Gopherus agassizii I Geochelone nigra accounts

HABITAT

Tropical evergreen and deciduous forests.

BEHAVIOR

Males use stereotyped head movements to identify other males. If a turtle does not respond with head movements, the male sniffs its cloacal region, presumably to confirm the sex and species. A returned head response elicits combat, in which males ram one another even to the point of one overturning the other.

FEEDING ECOLOGY AND DIET

This species is mostly herbivorous, feeding on fallen fruit, succulent plants, grasses, and mushrooms, but also eating termites and carrion.

REPRODUCTIVE BIOLOGY

This tortoise may mate throughout the year. During courtship the male pushes or rams the female's shell and bites at her limbs to immobilize her. He mounts the female's shell from the rear for copulation, during which time his head and neck are fully extended forward and downward, his mouth is open, and he may make clucklike vocalizations. The nesting season is very extended and it has been suggested that it might occur year-round. Multiple clutches are produced at intervals of about one to two months. Captive females have produced up to four clutches per year. The eggs are brittle-shelled but their shape varies from spherical to elongate and from 1.6 to 2.4 in (40 to 60 mm) in greatest length by 1.4 to 2.2 in (35 to 56 mm) in width. Egg mass may range from 1.4 to 4.0 oz (41 to 112 g), averaging about 2.5 oz (72 g). Clutch size ranges from one to 12 eggs, although clutches of four to six are most common. Incubation requires 128-152 days (mean 136). The effect of temperature on sex during development is not known.

CONSERVATION STATUS

This species is listed as Vulnerable on the IUCN Red List. Forest cutting is increasingly affecting this species.

SIGNIFICANCE TO HUMANS

These tortoises are eaten regularly by local peoples and also are collected in low numbers for the pet trade. ♦

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