(Siebenrock, 1903b)
African pancake tortoise
Recognition
The keelless, hingeless carapace (to 17.8 cm) is extremely flattened (some individuals are even swaybacked) and has nearly parallel sides. Lateral marginals are sometimes slightly upturned; posterior marginals are usually smooth in larger adults but may be slightly serrated in juveniles. There are 11 or 12 marginals on each side, and two supracaudals are present. Submarginal scutes are absent. The cervical scute is long and narrow in adults, and the vertebrals are broader than long with the middle three smallest. The 1st vertebral may be slightly pointed anteriorly, and the 5th is flared. There is usually an indentation in the cervical region and, posteriorly, only a single suprapygal bone is present. The most unique feature of the carapace is the retention of the juvenile fenestra (windowlike openings between the carapacial bones) into adulthood (M. tornieri; carapacial bones; M. tornieri; carapacial bones 2). This condition is found in the hatchling stage of all tortoises, but these openings, at least in the dermal shell, usually close by adulthood. Some resorption of the endochondral ribs occurs in Malacochersus, which also occurs in other tortoises, the costal and peripheral bones are thin, and the neural bones are also shortened and weakened. These adaptations allow much flexibility in the carapace and permit the pancake tortoise to crawl into narrow crevices or under rocks to avoid predators and the heat of the sun. Apart from the fenestration, Loveridge and Williams (1957) felt the shell to be emydid-like and rather primitive. The entire morphology and development of the shell in Malacochersus has been well-studied by Procter (1922). The carapace is yellow to tan with light areolae on the vertebrals and pleurals, and darker scute borders. Width of these dark scute borders is extremely variable, even within a single clutch, no two individuals look alike, and many have radiating yellow stripes crossing the dark borders. These variable patterns tend to camouflage the turtle in its natural dry habitat. The hingeless plastron is also persistently fenestrated (M. tornieri; plastral bones). Its forelobe is only slightly anteriorly projecting, and the paired gular scutes are much broader than long, giving the appearance of lying transversely rather than longitudinally. There is a slight anterior notch between the gulars, and occasional individuals may also have an additional intergular scute. The hindlobe is posteriorly notched. Two, (rarely three) small axillary scutes and two to four inguinals are present on the bridge. The plastral formula is: abd > hum > pect >< fem > gul > an. The plastron is yellow with solid brown blotches or jagged brown radiations. The yellow-brown head is moderate in size with a nonprotruding snout and a hooked upper jaw which may be bi- or tricuspid. The premaxillae are ridgeless, but the triturating surfaces of the maxillae contain strong ridges. The edges of the jaws are slightly serrated. The prootic is well-exposed dorsally and the quadrate encloses the stapes. The supranasal scales are large and usually in contact. There are also a single or double prefrontal scale and a large, sometimes subdivided, frontal scale. The other head scales are small. Limbs and tail are yellow brown. The toes lack webs but bear strong claws. The anterior surface of the forelimb is covered with large overlapping scales.
The karyotype is 2n = 52 (Dowler and Bickham, 1982).
Males have longer, thicker tails than do the slightly larger females.
Distribution
Malacochersus tornieri occurs in East Africa from Njoro east to Malindi in Kenya, southward in Tanzania to Busisi, Smith Sound, Lake Victoria, and southeastward through Ugogo to Lindi on the Indian Ocean (Loveridge and Williams, 1957).
Geographic Variation
No subspecies are currently recognized.
Habitat
Malacochersus tornieri occupies a small home range in arid scrub and thornbush thickets with abundant boulders, flat rocks and rocky outcrops on low hills, and savannahs and woodlands at altitudes to over 1800 m.
Natural History
Males are pugnacious towards one another, especially just prior to the mating season, and Kirkpatrick (1993) has reported that male combat prior to breeding has led to better reproductive success. Loveridge and Williams (1957) and Broadley (1989g) reported courtship consisted of the male biting the limbs of the female as he trailed her, at times climbing on her back and biting at her head. Males may also crawl beneath females and try to overturn them. However, in captivity numerous cases have been reported in which, except for chasing, no aggression from the male towards females occurred (Wilke, 1983; Darlington and Davis, 1990; Schmalz and Stein, 1994; Loehr, 1997b). Loveridge and Williams (1957) observed mating in January and February, and Moll and Klemens (1996) found gravid females in June.
Nesting in Africa seems to occur in July and August (Loveridge and Williams, 1957), but in captivity this tortoise has produced clutches over most of the year (Pauler, 1988; Darlington and Davis, 1990; Schmalz and Stein, 1994; Loehr, 1997b). The female digs a nest cavity about 7.5-10.0 cm deep in loose sandy soil. In captivity, females often tuck the eggs away in out-of-the-way places in the cage (Kirkpatrick, 1993).
One or occasionally two elongated (37-50 x 22-39 mm), hard-shelled eggs are laid in each clutch; captives may oviposit every 4-8 weeks (Kirkpatrick, 1993; Loehr, 1997b). Hatching in the wild may occur in December. In captivity, the incubation period of the eggs varies from 140-300 days. Development of the egg seems to be triggered by a lowering soil moisture content of the incubation substrate (Schmalz and Stein, 1994; Loehr, 1997b). Unlike their flattened parents, hatchlings have slightly domed carapaces about 37-40 mm long.
Most activity is during the morning hours or in the late afternoon and early evening. Feeding occurs early in the morning and dry grasses and vegetation are predominantly eaten. In captivity, grasses, lettuces, squash, carrots, broccoli, green beans, cabbage, melons, apples, pears, bananas, and tomatoes are readily accepted, but animal foods are shunned (Kirkpatrick, 1993; Carl H. Ernst, pers. obs.).
The pancake tortoise is quite agile and a good climber. It is seldom found far from its rock home, and when disturbed, the tortoise makes a dash for the nearest rocks where it wedges itself under a rock or within crevices between rocks. The pliability of its shell aids in this, and it was previously thought that the tortoises inflated their lungs to help expand the shell to lock them into place. However, Ireland and Gans (1972) have shown that no significant or sustained increase in intrapulmonary pressure is associated with this wedging action. Instead, the tortoises dig in their foreclaws and rotate the forelegs outward to maintain their position in the rocks. Wild and captive specimens often bask, and Loveridge and Williams (1957) reported that they may aestivate beneath flat rocks during the hottest months.
IUCN Red List Status (1996)
Vulnerable (A1bd).