Karoo girdled lizard (Cordylus polyzonus)

Also known as:	African spiny-tailed lizard, smooth-backed girdle-tailed lizard

Kingdom	Animalia
Phylum	Chordata
Class	Reptilia
Order	Squamata
Family	Cordylidae
Genus	Cordylus (1)
Size	Average snout-vent length: 9 – 10.5 cm (2) Maximum snout-vent length: 11.3 cm (2)

Listed on Appendix II of CITES (1).

This spiny, yet attractive lizard is a characteristic feature of many rocky outcrops in arid parts of South Africa. Heavily armoured, thick scales run down the back and tail, with sharp spines protecting the soft, vulnerable underparts from potential predators (3). Colouration in adult Karoo girdled lizards varies greatly between regions, and individuals may display turquoise, olive-brown, or reddish-brown patterning, while black morphs occur in coastal regions (3) (4). However, all populations retain a distinctive black spot on the side of the neck, between the ears and the front limbs. Juvenile colouration is more consistent, but equally attractive, with prominent dark-brown banding on a yellow-brown body, checked with cream (3).   

The Karoo girdled lizard possibly has the widest range of any  cordylid, and is found throughout the Karoo region of western South Africa, northwards, into southern Namibia (3).   

The Karoo girdled lizard inhabits rocky outcrops in semi-desert areas, with succulent karroid and renosterveld vegetation, characteristic of the Karoo region. It typically inhabits lower altitudes within its range (3).

Highly conspicuous during the day, this diurnal lizard can be seen basking on rocky outcrops, soaking up the sunlight to heat its body (5) (6). Hampered by the weight of the body armour, the Karoo girdled lizard moves slowly, making it vulnerable to predation and, as a result, individuals never stray far from the protection of a rocky crevice (5). If a predator is sighted, it will retreat into a defensive cavity, and the spiny tail will curl around the body, presenting an impregnable defensive barricade to the predator. The Karoo girdled lizard is a sit-and-wait predator, lingering close to its crevice, waiting for beetles and grasshoppers to pass, before making short bursts to catch its prey. However, juveniles are more active foragers, and will travel further in search of food (3). 

Unusually for a lizard, the Karoo girdled lizard is gregarious, and small groups will occupy the same rocky outcrop. Individuals may hibernate during the winter in a tunnel dug in the soil beneath a boulder, before the breeding season commences in late spring (3). The Karoo girdled lizard is ovoviviparous, meaning fertilised eggs are retained inside the female’s body, and the female gives birth to between one and five live young in late summer (7).

In common with other cordylids, the attractive Karoo girdled lizard is a sought after pet species. As it is a relatively slow moving animal that can be easily located and collected from rocky outcrops, it is particularly vulnerable to overexploitation, and it may be threatened by illegal collection. However, at present, it is unclear how detrimental an effect this may be having on the population (3).

There are no specific conservation measures in place for the Karoo girdled lizard, but it is listed under Appendix II of the Convention on the International Trade in Endangered Species (CITES), meaning that international trade in this species must be carefully monitored (1) (3). 

For more information on the Karoo girdled see:

• Branch, B. (1998) Field Guide to Snakes and other Reptiles of Southern Africa. Ralph Curtis Books Publishing, Florida.

Authenticated (02/06/2010) by Jaco van Wyk, scientist and teacher, Pretoria, South Africa.

• Diurnal: active during the day.
• Gregarious: tending to form a group with others of the same species by habitually living or moving in flocks or herds rather than alone.
• Hibernation: a winter survival strategy in which the animal passes the winter in a resting state. This period of inactivity is characterised by specific biological and biochemical changes including lowered blood pressure and respiration rate. In reptiles, this is also known as brumation.
• Karoo: a semi-desert region of South Africa.
• Karroid: used to describe vegetation types typical or reminiscent of the semi-desert Karoo region of South Africa, namely sparse vegetation dominated by dwarf, perennial (living more than one year) shrublets.
• Ovoviviparous: ovovivipary is a method of reproduction whereby the egg shell is weakly formed and young hatch inside the female; they are nourished by their yolk sac and then ‘born’ live.
• Renosterveld: a type of fire-prone shrubland vegetation, characterised by a dominance of members of the daisy family. Renosterveld grows in fertile, clay-rich soils, where the annual rainfall is between 300 and 600 millimetres.

1. CITES (January, 2010)
   http://www.cites.org/
2. Branch, B. (1998) Field Guide to Snakes and other Reptiles of Southern Africa. Ralph Curtis Books Publishing, Florida.
3. SCARCE: Survey of Cederberg Amphibians and Reptiles for Conservation and Ecotourism (January, 2010)
   
   http://academic.sun.ac.za/capeherp/cederberg/cordylidskaroogirdled.htm
4. Mouton, P.LE.F.N., Nieuwoudt, C.J., Badenhorst, N.C. and Fleming, A.F. (2002) Melanistic Cordylus polyzonus (Sauria: Cordylidae) populations in the Western Cape, South Africa: Relics or ecotypes? Journal of Herpetology, 36: 526-531.
5. Losos, J.B., Mouton, P.F.N., Bickel, R., Cornelius, I. and Ruddock, L. (2002) The effect of body armature on escape behaviour in cordylid lizards. Animal Behaviour, 64: 313 - 321.
6. Alexander, G. and Marais, J. (2007) A Guide to the Reptiles of Southern Africa. Struik Publishers, Cape Town.
7. J. Craig Venter Institute (January, 2010)
   http://www.jcvi.org/