Black girdled lizard

A black girdled lizard (Cordylus niger) busy scaling (note the tail).

Common Name: Black girdled lizard, swart-skurwejantjie (Afrikaans)

Derivation of scientific name: The genus name Cordylus Laurenti was established in 1768 and refers to the sideways swinging tail (when removed from their shelter), which is used like a club or cudgel; kordule (Greek) = club. The specific epithet ‘niger’ refers to the jet black colour of this lizard’s body.

The black girdled lizard belongs to the genus Cordylus, which has 21 known species and are endemic to sub-Saharan Africa. Cordylus niger is endemic to the Cape Peninsula, Western Cape, with an outlier population near Saldanha. The black girdled lizard is distinguished by melanistic (black) colouration and large, girdled, well-armed dorsal scales with pierced nostrils in the nasal shields.

 Most girdled lizards are crevice species, but there are a few exceptions. The black girdled lizard is locally abundant in rocky areas from sea level up to mountain tops, including on Table Mountain. It is an agile lizard that is active during sunny weather and it often gazes in the direction of the sun, which is why they are called sonkykers (sun gazers) in Afrikaans. Another apt Afrikaans name is ouvolk (direct translation: ‘old folk’), which alludes to their ancient, crocodilian appearance. At the Kirstenbosch National Botanical Garden black girdled lizards are often seen just above the cultivated garden where they take shelter in cut-down Eucalyptus (blue gum) stumps.

Girdled lizards are popular in the pet trade and are also used for traditional medicine. The black girdled lizard is listed as Near-Threatened (NT) in the Red List (Mouton et al. 2014).

Description

The black girdled lizard is a medium-sized lizard (~7 cm long), with a depressed head and smooth head shields. It is distinguished by its pitch or jet black colouration and large-girdled, dorsal, well-armed scales with pierced nostrils in the nasal shields. The upper (dorsal) scales are square and imbricate (like a tile roof) and are arranged in more than 22 regular rows. The lower scales (ventral) are also square and are in regular transverse series. The limbs are moderately long and have saw-edged scales.

The black girdled lizard (Cordylus niger) – never venturing far from its rock crevice.

Getting around
The black girdled lizard has four short, stout legs with strong claws that are well adapted to living in rocky terrain.

Communicating:

Members of the genus Cordylidae have two types of epidermal glands – femoral and generation glands – which are used for chemical communication. Femoral glands secrete waxy material that acts as territorial markings, while generation glands are thought to be for communication with other members of the species.

Distribution

The black girdled lizard is endemic to the extreme southwestern coastal region of the Western Cape, South Africa. Localised subpopulations are known to occur in Saldanha, Langebaan Peninsula, Jutten Island and the Cape Peninsula.

Habitat

The black girdled lizard (Cordylus niger) is mainly confined to rocky outcrops, following mainly the quartzitic sandstone of the Cape Super Group Formation. At Saldanha they live in granitic outcrops. They can also be found in urban regions (Cape Town), for example in gardens where there is sufficient shelter. The black girdled lizard is a rock-dwelling (rupicolous) lizard, and is territorial and never ventures far from its shelter in a rock crevice, dashing back when alarmed. They take shelter in narrow rock crevices, orienting their tail to cover the rest of their body, and will inflate themselves to lock into the rock crevice when necessary.

Food

Black girdled lizards eat mainly insects, but occasionally will take some vegetable matter.

SEX and LIFE CYCLE

Sex

The black girdled lizard (and other species in the genus) is ovoviviparous, meaning that the fertilised eggs remain inside the female’s body until they are ready to hatch and the female gives birth to live young. Breeding is during the autumn when one to three young are born. The young are immediately self-sufficient and there is no parental care. They reach maturity within three years.

A pregnant black girdled lizard (Cordylus niger) on a rock slab at Cape Point Nature Reserve

Family life

The black girdled lizard is solitary and only seeks out mates during the breeding season. Although it is solitary, it is common and found in large numbers around rocky habitats. The black girdled lizard is diurnal and spends most the day basking in the sun and waiting to ambush insects that fly or crawl past. It is active throughout the year and does not hibernate. However, during cold rainy weather it often retreats into rocky crevices.

THE BIG PICTURE

Friend and Foes

The black girdled lizard is prey to various snakes, mongooses and birds of prey.

Smart strategies

The black girdled lizard is well adapted to the cool environmental conditions found in the southwestern coastal region of the Western Cape, South Africa. These adaptations include:

1) Melanism: The jet black colouration has a thermo-regulatory function and acts as a sun energy trap even in cool and cold weather conditions. This is an effective adaptation to the relative cool coastal climate on the Cape Peninsula.  

2) Sit-and-wait (ambush) foraging strategy: Low energy outputs are required to capture prey in cold climates and enable the lizards to spend more time basking in the sun in order to thermo-regulate their body temperature.

3) Ovoviviparous: It is hypothesised that ovoviviparity evolved as an adaption to cold environmental environments. In ovoviviparous females, fertilised eggs remain inside the body until they are ready to hatch and the female gives birth to live young. The black girdled lizard exposed to cool/cold environmental conditions are able to thermo-regulate and provide the developing embryo with ideal conditions as opposed to oviparous (egg-laying) species where low environmental temperatures are not ideal for optimum embryonic development.

4) Rock dwelling behaviour: Rocky habitats provide suitable open perching sites for basking in the sun, plus the heat capacity of rocks can be utilised for thermoregulation and the rocky habitats afford safety retreats (cracks and crevices) to hide from potential predators.

Poorer world without me

The black girdled lizard is an insectivore and is important in regulating natural insect populations.

Cape Point Nature Reserve, near the light house, habitat of the black girdled lizard (Cordylus niger).

Conservation status and what the future holds

The black girdled lizard is not endangered; in fact it is common and abundant in rocky habitats around the Cape Peninsula. In South Africa however, all members of the genus Cordylus are protected by strict conservation laws mainly as a result of illegal exporting, and they may not be caught nor kept as a pet without a permit. The black girdled lizard also has a small and restricted habitat, which makes it vulnerable to changes in land-use patterns in its natural range.  

Relatives

The genus Cordylus is comprised of 21 known species, of which 11 species occur in South Africa in small and restricted natural ranges. Cordylus aridus, C. cloeti, C. niger and C. oelofseni are endemic to the Western Cape; C. cordylus occurs in the Western Cape, Eastern Cape, southern parts of KwaZulu-Natal and eastern parts of the Free State. Cordylus imkeae is restricted to the Northern Cape; C. macropholis and C. mclachlani occur in the Northern and Western Cape, and C. jonesii occurs in southern parts of Zimbabwe and Mozambique, eastern parts of Botswana and Swaziland and northeastern provinces of South Africa (North West, Limpopo, Gauteng, Mpumalanga and KwaZulu-Natal). The last species, C. vittifer, is endemic to the northeastern parts of South Africa, Swaziland and southeastern Botswana.

References and further reading

  • Branch, B. 1998. Field guide to the snakes and other reptiles of southern Africa. Struik.
  • Gotch, A.F. 1995. Latin names explained. Blanford Press, London.
  • Fitzsimons, V.F. 1943. The lizards of South Africa. Pretoria: Transvaal Museum Memoir 1.
  • Mouton, P.N., Bates, F.B. & Whiting, M.J. 2014. Cordylidae. In M.F. Bates, W.R. Branch, A.M. Bauer, M. Burger, J. Marais, G.J. Alexander & M.S. de Villers (eds). Atlas and Red List of the reptiles of South Africa, Lesotho and Swaziland. Suricata 1. South African National Biodiversity Institute, Pretoria.

Author
Ernst van Jaarsveld
Kirstenbosch National Botanical Garden
June 2014

Scientific Name Cordylus niger Cuvier, 1829

Classification:

Class Reptilia

Order Squamata

Family Cordylidae

Genus Cordylus 

Species C. niger

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