(Schweigger, 1812)
South African bowsprit tortoise
Recognition
The elongated, hingeless carapace (to 30 cm) is domed with the sides dropping abruptly. The cervical scute, if present, is narrow, and there is a deep anterior notch in the cervical region. Anterior marginals are expanded but smooth bordered, lateral marginals not upturned or flared, and posterior marginals somewhat expanded and downturned. A single suprapygal is present; submarginals are absent. The vertebral scutes are wider than long; the 1st is largest and narrows to an anterior point, the 2nd is shortest, and the 5th is flared posteriorly. Anterior neural bones are usually hexagonal while the others are variable and approach octagonal and quadrilateral shape (Loveridge and Williams, 1957). The carapace is yellowish brown to olive with wide dark borders and dark centers on each vertebral and pleural, and a narrow dark triangle at the anterior seam of each marginal. The unhinged plastron has the epiplastral portion of the forelobe thickened and somewhat protruding, and covered only by a single gular. Its hindlobe has a posterior notch. The plastral formula is: abd > gul > hum >< an > fem >< pect. The plastron is yellow to reddish with a broad central black blotch. Undersides of the anterior marginals are yellow, and those posterior to the inguinal have a black spot. The head is moderate in size; its snout does not protrude and the upper jaw is hooked (sometimes bi- or tricuspid). The prefrontal scale is divided longitudinally, and sometimes separated from the large, single frontal by a small scale (Loveridge and Williams, 1957). Premaxillae and maxillae lack ridging, but the edges of the jaws are weakly serrated. The quadrate usually encloses the stapes, and the anterior palatine foramina are large. The face is usually black or dark brown; the top of the head is often yellow. Forelimbs are anteriorly olive to brown with large yellow scales along the outer border and yellow posteriorly. Hindlimbs are dark on the outer surface and yellow beneath. The toes bear strong claws.
Males have plastra with a deep posterior concavity and a stronger gular projection, and longer, thicker tails; they generally are larger than females.
Distribution
Chersina angulata is found along the coastline of the Cape Provinces, South Africa at elevations to 900 m. Namibian records are questionable (Greig and Burdett, 1976).
Geographic Variation
Interpopulation variation has been little studied, and no subspecies have been named. A study by Van den Berg and Baard (1994) revealed that females from the western Cape Province are smaller than those from other parts of its range; males do not show a significant size difference. Van Heezik et al. (1994) reported that the population introduced onto Dassen Island, South Africa at the beginning of this century now contains a greater proportion of larger males and females than do mainland populations.
Habitat
Chersina angulata in southern Africa is associated with coastal fynbos, mesic thicket and transitional karooid scrubland (Chersina angulata biotope). It rarely enters grassland.
Natural History
During courtship, males pursue and bite at the legs and tail of the female. Males also bite, ram, push, and hook other males with their gular projections while attempting to overturn them during dominance combat bouts.
Mating occurs throughout the year, but most commonly in September-April (Branch, 1989a). Nesting occurs in August when the female digs a 75-100 mm-deep hole to deposit her single egg (occasionally two eggs are laid). The egg is 34-43 x 24-35 mm (Branch, 1989a), and brittle-shelled. Natural incubation may last from 180 days to 12 or 14 months (Loveridge and Williams, 1957), and hatchlings have flattened shells 30-39 mm long (Branch, 1989a).
C. angulata eats grasses, annual plants, and snails (Branch, 1989a). Captives do well on lettuce and other greens, bean and pea pods, and various fruits, and they can sometimes be induced to eat raw beef and canned dogfood. Eglis (1962) has described the olfactory movements of this turtle while smelling food as one or several basically straightforward motions with or without sideways oscillation at completion.
IUCN Red List Status (1996)
Not listed.