(Kuhl, 1820)
African serrated star tortoise
Recognition
The carapace (to 14.7 cm) is widest behind the center, domed with abruptly descending sides, shallowly notched at the large cervical, and strongly serrated along both the anterior and posterior rims. Vertebrals are broader than long. Each carapacial scute is covered with concentric growth annuli, but the centers of the vertebrals are not raised in a conical or pyramidal fashion, as in P. geometricus. There are 10 to 12, but usually 11, marginals on each side, and the supracaudal is not divided. The carapace is dark-brown or black, with yellow to dark-orange rays on each scute (6-10 rays on each vertebral and pleural). The plastron is large and well-developed. Its forelobe tapers to the front, is about the same width as the hindlobe, and bears a shallow anterior notch; the gulars are slightly divergent. The hindlobe tapers toward the rear and has a deep posterior notch. Single axillary and inguinal scutes occur on each bridge; the axillary usually is fused to the humeral. The plastral formula is: abd > hum > gul >< fem >< an > pect. Each plastral scute usually has a yellow center from which extend yellow and dark-brown or black rays. The head is small to moderate in size with a convex forehead, a nonprojecting snout, and a hooked, often tricuspid, upper jaw. Its prefrontal scales are subdivided or divided longitudinally, and are followed by subdivided frontal scales. Other head scales are small. Head and neck are tan to brown with some yellow markings; jaws are yellow. The brown forelimbs have on their anterior surfaces a few large, irregularly shaped, nonoverlapping scales in two to four longitudinal rows. The brown hindlimbs have a large and occasionally also a few smaller tubercles on the thighs.
Males are smaller than females and have concave plastra and longer, thicker tails; Loveridge and Williams (1957) reported the supracaudal scute is not curved in males but downwardly directed in females.
Distribution
Psammobates oculiferus ranges in southern Africa from Northern Province, North-West, Mpumalanga and the western Free State northwestward through the Kalahari Desert of Botswana and Namibia almost to Angola.
Habitat
The habitat is brush or savannah areas with sandy soils (Psammobates oculiferus biotope). In the Transvaal area, Psammobates oculiferus has been found aestivating from March to September up to half buried in red sand, under the scanty shelter of fallen Acacia branches (Milstein, 1968).
Natural History
Courtship has been observed in late November and consisted of the male scuttling around the female, butting her shell, and periodically emitting short, low, grunting coughs (Loveridge and Williams, 1957). Mating in the wild takes places from September to December. A clutch contains 2-4 oval (30-40 x 23-31 mm) eggs (Boycott and Branch, 1989).
All foraging is at ground level. During dry years P. oculiferus eats those plants that are most readily available, mostly succulents but also grasses. More ephemeral plants are consumed during wet years. Rall and Fairall (1993) reported that of 70 species of plants available in their study area in southern Africa only 38 were used for food. Thirty species were eaten during dry years, with Crotalaria sphaerocarpa (15.8% incidence in scats) and Nemesia fruticans (12.9%) being most popular (all other species had a less than 10% occurrence in scats). During wet years 17 species were used as food, but none were found in over 10% of the scats; the most commonly eaten plants were Tribulus terrestris (9.4%), Aristida congesta (7.6%), and Indigofera alternus (7.6%).
Aestivation occurs during the cold, dry months of May-August (Boycott and Branch, 1989).
IUCN Red List Status (1996)
Not listed.