Pyxis planicauda

(Grandidier, 1867)
Flat-shelled spider tortoise

The carapace (to 13.7 cm) is somewhat flattened dorsally. Each vertebral and pleural has a light brown or yellow center surrounded by a wide dark brown or black border, and in older tortoises an additional yellow border surrounds the dark border. Yellow rays extend outward from the centers of these scutes across the dark border (usually 4-9 on each vertebral, 2-4 on each pleural). Each marginal is dark with a yellow stripe. The neural bones are either hexagonal or squared. The plastron is hingeless, and the hindlobe lacks a posterior notch. The anal scutes are somewhat rounded posteriorly. The plastral formula is abd > hum >< fem >< pect > an > gul. The plastron is yellow with some scattered dark blotches or radiations on the sides. The maxillae have a slight median ridge, but the sides of the upper jaws lack serrations. The quadrate encloses the stapes and the anterior palatine foramina are small. The head is dark brown or black with some variable yellow markings. The tail is noticeably flattened.

Pyxis planicauda occurs on the southwestern coast of Madagascar, between the Monrondava and Tsiribihina Rivers (Behler et al., 1993).

Geographic Variation

This species lives in deciduous forests in hot, semi-arid habitats (Kuchling and Bloxam, 1988).

Natural History
Clutches contain only one egg. Pritchard (1979) reported that the egg is relatively large and slightly ovoid, and Bour (1981a) wrote that it is 33-35 mm long by 25-30 mm wide.
Foods consist of fallen fruits from trees (Moraceae, Rubiaceae), and the shoots and leaves of bushes (Kuchling and Bloxam, 1988).
Pyxis planicauda is only active during the rainy season, most often during and after rains (Kuchling and Bloxam, 1988; Bloxam et al., 1993). During the dry season, it buries itself in the leaf litter of the forest floor (Kuchling and Bloxam, 1988).

IUCN Red List Status (1996)
Endangered (A1cd, B1+2bcd).