Cordylids (Cordylidae; gordelakkedisse)
Armadillo Lizard / Blinkogie, Geel Thysie
Size Males reach larger body sizes than females and also have larger heads and longer tails. Maximum snout-vent length recorded for males is 125 mm and for females 116 mm.
Description This species is heavily armoured with sharp spines on the sides of the neck, body, dorsal parts of limbs, and the tail. The head is heart-shaped when viewed from above and the head shields are strongly rugose.
Its body colour varies from dirty yellowish-brown to straw colour. The dorsal coloration is mostly uniform, but sometimes the sides can have an orangy or olive tinge. Sometimes irregular infusions of dark brown occur on the back. The lips and lower half of the nasals are dark brown to black. The throat is yellowish with dark brown to black blotchy reticulations.
Biology The armadillo lizard is a strict rock-dweller. It lives in groups of 2-60 individuals, which may occupy a single crevice for long periods. Groups prefer horizontal crevices with an accompanying ledge on which the lizards can perch in close proximity to the crevice to feed and bask. This comparatively sluggish lizard exhibits the peculiar habit of gripping its tail firmly in the mouth and rolling into a tight ball when alarmed by handling. It will maintain this position for as long as danger threatens. It is keen-sighted and the whole group will disappear like magic into a crevice when danger threatens. Smaller groups normally include only one adult male and varying numbers of adult females and juveniles, but larger groups may have several adult males. Mating takes place in early spring and usually only one baby is born in autumn. Interestingly, the embryo usually develops in the left uterus of the female. Male and female gonadal cycles are syncronised. The diet consists mainly of insects, but centipedes and scorpions are also occasionally taken. After the spring rains, it feeds voraciously on termites which then appear in large numbers. The heavily armoured body and tail biting behaviour probably allow the armadillo lizard to venture some distance away from its crevice when termites are abundant. The species becomes inactive during dry summer months when food is scarce.
Distribution The armadillo lizard occurs along the west coast of South Africa, from the Orange River in the north to the Piketberg Mountains in the south and reaching inland as far as Matjiesfontein in the western Karoo .
Distribution in GCBC The distribution of the armadillo lizard within the Corridor appears to be very patchy. It is absent at high altitudes and in the southern parts of the Corridor.
Conservation status Listed as Vulnerable in the latest South African Red Data Book for reptiles and amphibians, as well as 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 Although fairly common within its distributional range, it is listed as vulnerable in the South African Red Data Book for Reptiles and Amphibians owing to its popularity as a pet. Its attractive appearance, the fact that it lives in groups and is easily captured and tamed, makes it particularly vulnerable.
Current studies M.Sc.-student, Jeanine Hayward, is investigating group dynamics and anti-predator advantages of group-living in this species.
Cindy Shuttleworth recently completed her M.Sc. study on the ecology of the armadillo lizard in the Greater Cederberg area. Jeannie Hayward, honours student is investigating the significance of the group signal and the influence it has on shelter selection of armadillo lizards.
Other recent studies on this species include:
EFFENBERGER, E. & MOUTON, P. le F. N. 2007. Space use in a multi-male group of the group-living lizard.
Journal of Zoology 272 : 202-208
ALBLAS, A. 2004. Cloacal glands of the group-living lizard, Cordylus cataphractus. Unpublished M.Sc. thesis, Department of Zoology, University of Stellenbosch.
BERRY, P.E. 2002. Does the group-living lizard, Cordylus cataphractus, benefit from safety in numbers? Unpublished Honours project, Department of Zoology, University of Stellenbosch.
COSTANDIUS, E. 2002. The effect of intergroup distance on group fidelity and juvenile dispersal in the group-living lizard, Cordylus cataphractus. Unpublished Honours project, Department of Zoology, University of Stellenbosch, South Africa.
EFFENBERGER, E. 2004. Social structure and spatial use in a group-living lizard, Cordylus cataphractus. Unpublished M.Sc., thesis, Department of Zoology, University of Stellenbosch.
FLEMMING, A.F. & MOUTON, P.LE F.N. 2002. Reproduction in a Group-Living Lizard, Cordylus cataphractus (Cordylidae), from South Africa. Journal of Herpetology 36 : 691-696.
GLOVER, J. 2002. The temporary status of solitary individuals in the group-living lizard, Cordylus cataphractus. Amphibia-Reptilia (under review). Unpublished Honours project, Department of Zoology, University of Stellenbosch, South Africa.
MOUTON, P.LE F.N., FLEMMING, A.F. & KANGA, E.M. 1999. Grouping behaviour, tail biting behaviour, and sexual dimorphism in the armadillo lizard ( Cordylus cataphractus ) from South Africa. Journal of Zoology London 249: 1-10.
MOUTON, P.LE F.N., FOURIE, D. & FLEMMING, A.F. 2000. Oxygen consumption in two cordylid lizards. Amphibia-Reptilia 21: 502-507.
MOUTON, P.LE F.N., GEERTSEMA, H & VISAGIE, L. 2000. Foraging mode of a group-living lizard, Cordylus cataphractus (Cordylidae). African Zoology 35: 1-7.
RETIEF, D.J. 2000. Geographical variation in group size, body size and number of epidermal glands in the group-living lizard, Cordylus cataphractus (Cordylidae). Unpublished Honours project, Department of Zoology, University of Stellenbosch, South Africa.
VISAGIE, L. 2001. Grouping behaviour in the armadillo lizard, Cordylus cataphractus. Unpublished M.Sc. thesis, University of Stellenbosch, South Africa.
VISAGIE, L., MOUTON, P.LE F.N. & BAUWENS, D. 2005. Experimental analysis of grouping behaviour in cordylid lizards. Herpetological Journal 15:91-96.
VISAGIE, L., MOUTON, P.LE F.N., & FLEMMING, A.F. 2002. Intergroup-movement in a group-living lizard, Cordylus cataphractus, from South Africa. African Journal of Herpetology 51: 75-80.