Madagascan bigheaded turtle

Erymnochelys madagascariensis

TAXONOMY

Dumerilia madagascariensis Grandidier, 1867, "Mouroundava Tsidsibouque flumina in occidentali insulae Madagascar lit-tore" (Morondava and Tsidibou rivers on the western coast of Madagascar). No subspecies are recognized.

OTHER COMMON NAMES

None known.

PHYSICAL CHARACTERISTICS

Madagascan big-headed turtles are medium-sized, sideneck turtles, with a maximum shell length of 19.7 in (50 cm), and a flattened oval carapace that lacks keels. The connection of the pelvis to the carapace contacts the suprapygals.

DISTRIBUTION

These turtles occur only in the western drainages of Madagascar.

HABITAT

This species inhabits slow-moving rivers, streams, ponds, and swamps.

BEHAVIOR

Very little is known about the behavior of Madagascan big-headed turtles. They apparently often spend the dry season buried in the mud.

FEEDING ECOLOGY AND DIET

These turtles are generally omnivorous, with adult females feeding primarily on the shoots of Phragmites, and the adult males feeding mainly on snails and fish. Juveniles eat both plant and animal material, including insects and crustaceans.

REPRODUCTIVE BIOLOGY

Nesting occurs primarily during October and November, but may extend beyond that month. Females lay one to three clutches in a season, but apparently reproduce only every other year. Clutch size ranges from 10 to 30, and eggs average 1.5 by 0.9 in (38 by 24 mm), and 0.4 oz (10.2 g). The effects of temperature on sex determination have not been studied.

CONSERVATION STATUS

This species is cited as Endangered on the IUCN Red List. SIGNIFICANCE TO HUMANS

These turtles are captured by humans for food in baited hoop nets or traps, on hook and line, with spears or harpoons, by diving for them, and on nesting beaches. The eggs are also taken from the nesting beaches. ♦

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