Cordylids (Cordylidae; gordelakkedisse)
Karoo Girdled Lizard / Likkewaanakkedis
Size Males and females are more or less of equal body size. Adult body size ranges from 90-105 mm.
Description A large girdled lizard with a flattened body, well-developed limbs, and a tail that is slightly longer than the body. The tail is moderately spinose and each whorl consists of two scale rows rather than one as in most other Cordylus species. The body scales are smooth and relatively small for a Cordylus . The lower eyelids have transparent discs. The nasal scales surrounding the nostrils are slightly tubular giving the nostrils a swolen appearance. Only males possess femoral and generation glands on the ventral aspect of the thigh. Adult coloration is extremely variable from region to region, but appears to be fairly conservative in juveniles. In the latter the back is yellow-brown, chequered with dark brown and pale cream and the tail is banded in dark-brown. In adults, the chequered pattern is usually less prominent than in juveniles or altogether absent, giving them a dark brown to black appearance. In the eastern parts of the Northern Cape, adults are olive-brown with bright orange flanks, while in the Darling area, individuals have a turquoise colour. Isolated melanistic populations occur along the west coast from Saldanha in the south to Alexander Bay in the north. All populations have a characteristic black blotch on the side of the neck between the ear opening and the front limbs.
Biology It is a rockdwelling species and individuals will occupy the same crevice for long periods of time. It is probably the most common species in the arid western and central parts of South Africa. It can typically be seen basking on rocks with the head and foreparts well-raised off the rock face. Unlike most other girdled lizards, it seems to prefer the warmer lowland areas and is usually absent from the top sections of the koppies and mountains within its range. It is a keen-sighted, agile lizard and will quickly disappear into its crevices when danger threatens. Typical of most girdled lizards when inside a crevice, the tail will be curled sideways to the front to shield the head and body from predators. Cranial kineses is well developed and allow the lizard to press hard with the head against the roof of the crevice to prevent from being pulled out by a predator. Suitable crevices are normally occupied by one lizard only.
Although they will spend most of their time basking close to the crevice, individuals may venture considerable distances away from their shelters for better basking spots. Members of this species are typical sit-and-wait foragers. Juveniles are often found among vegetation some distance from rocks and probably actively search for prey items. Reproductive cycles of the males and females are synchronised and mating occurs in early spring. Females give birth to 1-5 babies during late summer to early autumn. The occurrence of melanistic populations along the west coast correlates with upwelling of cold water in the Atlantic Ocean.
Distribution The Karoo Girdled lizard has the most extensive range of all the girdled lizards. It occurs in the central and western parts of South Africa, reaching northwards into southern Namibia. It is absent from the southern coastal regions.
Distribution in GCBC Probably occurs throughout the Corridor, but not at high altitudes.
Conservation status Not listed in the latest South African Red Data Book for reptiles and amphibians, or in the IUCN Red List of Threatened Species. Like all other cordylid species, it is listed internationally in Appendix II of the Convention on the International Trade in Endangered Species of Fauna and Flora (CITES); legislation which regulates the international trade in these animals.
Threats None identified.
Current studies None.
Recent studies include:
PROUST, N. 2005. Sexual size dimorphism in melanistic and non-melanistic populations in this species. Unpublished honours project. University of Stellenbosch.
MOUTON, P.LE F.N., NIEUWOUDT, C.J., BADENHORST, N.C., & FLEMMING, A.F. 2002. Melanistic Cordylus polyzonus (Sauria: Cordylidae) populations in the Western Cape, South Africa : Relics or ecotypes? Journal of Herpetology 36: 526-531.