(Bell, 1828)
African tent tortoise
Recognition
The carapace (to 14.5 cm) is oval to slightly elliptical, domed with abruptly descending sides, usually shallowly notched at the small cervical, and only slightly serrated anteriorly and posteriorly. Vertebrals 3-5 are broader than long, the 2nd may be as long as broad, the 1st (which is somewhat pointed anteriorly) is often longer than broad, the 5th is flared. Each carapacial scute is covered with growth annuli causing the centers of the vertebrals to be raised in a conical or pyramidal fashion. On each side lie 11 to 13 marginals, and the supracaudal is not divided. The carapace varies from yellow, orange, or reddish to yellowish brown. Each scute usually has light-yellow and black or dark-brown radiations (4-14 black rays on the vertebrals and pleurals, 1-4 on the marginals), but some P. t. verroxii have uniformly reddish brown or tan carapaces or yellow areolae (the bergeri form, a synonym of P. t. verroxii). The plastron is large and well-developed. Its forelobe is tapered to the front and about the same width as the hindlobe, and has only a shallow anterior notch with slightly divergent gulars. The hindlobe tapers toward the rear and bears a deep anal notch. There are two or three (rarely one) axillaries and an inguinal on each bridge; the axillaries do not fuse with the humeral scutes. The plastral formula is varied: abd > hum >< gul >< an >< pect >< fem. The plastron is yellow to orange, sometimes uniform, but usually with some pattern of dark pigmentation (see geographic variation). The head is small to moderate with a slightly convex forehead, a nonprojecting to slightly projecting snout, and a hooked, bi- or tricuspid, upper jaw. Its prefrontal scales may be divided longitudinally or they may be subdivided, the frontals are subdivided, and other head scales are small. Head, neck, and limbs are grayish brown to yellowish or reddish brown to tan. There may be some dark pigment on the head and the snout may be yellow. Large irregularly shaped, overlapping scales lie in two to four longitudinal rows on the anterior surface of the forelegs. Usually one or more large tubercles occur on the thigh, and there are spurlike scales at the heel of the hind-foot.
Males have concave plastra and longer, thicker tails. Females are larger than males.
Distribution
Psammobates tentorius ranges from the Great Namaqualand of Namibia southeastward to Eastern Cape, South Africa.
Geographic Variation
Psammobates tentorius is highly variable, and a great number of names have been applied to its various pattern forms (see Loveridge and Williams, 1957, for a discussion of these names); however, currently only three subspecies are considered valid. P. tentorius tentorius (Bell, 1828), the common tent tortoise, occurs at elevations below 900 m in the southern and eastern Karoo from Grahamstown to Matjiesfontein, Republic of South Africa. It has a well-defined plastral pattern consisting of a dark central blotch which may extend outward along the seams, but lacks yellow radiations. The carapace often has 13 marginals on each side, and the vertebral centers are conically raised; 8-12 black rays occur on each vertebral, 12-14 on each pleural, and 3-4 on each marginal. P. t. trimeni (Boulenger, 1886), the western tent tortoise, occurs at elevations below 900 m in extreme western Cape Provinces from Lambert's Bay north to beyond the Orange River in Great Namaqualand in Namibia (Loveridge and Williams, 1957). It has a well-defined plastral pattern in which the central dark blotch is crossed by yellow radiations or is indented by a series of light encroachments from the ground color. The carapace has no more than 12 marginals on each side, and the vertebral centers are conically raised; four to eight black rays occur on each vertebral and pleural, and three or four on each marginal. The northern tent tortoise P. t. verroxii (Smith, 1839) ranges at elevations over 900 m from the Northern Cape Province northwestward into the Great Namaqualand of Namibia (Loveridge and Williams, 1957). DeWaal (1980) did not find it in the southern Free State, although Loveridge and Williams (1957) reported it occurred there. This subspecies has a yellow plastron which may totally lack dark pigment, but when dark markings are present they are random in manner, not presenting a uniform outline. The carapace has no more than 12 marginals on each side, and the vertebral centers are flattened and not conically raised; there are five or six black rays on each vertebral and pleural of which the anterior pairs meet the posterior pairs from the next forward scute to form ocelli; one to three rays occur on each marginal.
According to William R. Branch (pers. comm.), a modern re-assessment of this species is required, as its subspecies are poorly defined, the intergradation zone between all subspecies is very large, and only occassionally one finds true 'races' in the centers of their presumed ranges.
Habitat
The tent tortoise lives in various habitats within its range: sandy desert, scrub brush and (only marginally in) arid savannah, both on the flats and rocky outcrops. In the cooler parts of its range, it may hibernate from June to September, while others in warmer parts of the range may aestivate in summer.
Natural History
Eglis (1962) described olfactory motions, possibly associated with courtship, in the various subspecies as follows: Psammobates tentorius tentorius, a well-pronounced, swinging, figure-eight-shaped sideways motion; P. t. trimeni, a swinging, hook-shaped sideways motion; and P. t. verroxii, a double or triple swinging or a single hook-shaped sideways motion, sometimes a double-jointed movement consisting of a forward motion with a subsequent sideways motion to either side.
Mating has been recorded in October and November, and nesting in September-January (Branch, 1989e). Only one (P. t. trimeni and P. t. verroxii) or two or three (P. t. tentorius) eggs are laid in the single yearly clutch. Eggs are almost ellipsoidal (27-34.5 x 21-24 mm) and have brittle shells. Hatching occurs in April or May, and the hatchling carapace is 25-30 mm long. Near Aus, Namibia, a few weeks-old hatchling P. t. trimeni (31.4 mm; 7 g) was encountered in September, three weeks after rain had moistened the desert region (Loehr, 1998).
Feeding occurs in the morning and late afternoon. Like other tortoises, P. tentorius is a vegetarian, feeding on grasses, sedges, and other short herbaceous plants.
IUCN Red List Status (1996)
Not listed.