Girdled and Plated Lizards (Cordylidae)

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Girdled and plated lizards

(Cordylidae)

Class Reptilia

Order Squamata

Suborder Sauria

Family Cordylidae

Thumbnail description
Small to large diurnal, heliothermic, terrestrial lizards, mostly with well-developed legs, although some groups are snakelike and have vestigial limbs

Size
Girdled and flat lizards, 5–13 in (13–33 cm); grass lizards, 22 in (56 cm); plated lizards, 6–28 in (15–71 cm)

Number of genera, species
7 genera; 88 species

Habitat
Forest, savanna, scrubland, desert, and grassland

Conservation status
Extinct: 1 species; Vulnerable: 5 species; Lower Risk/Near Threatened: 5 species

Distribution
Southern and tropical Africa and Madagascar

Evolution and systematics

The Cordylidae is the only lizard family restricted to Africa, with one subfamily also occurring on Madagascar. The fossil history is very poor, although some fossils (Pseudolacerta and Palaeocordylus) from the early Eocene to the early Miocene of Europe are provisionally assigned to the family. Relationships to other lizards also remain problematic, but they appear to be close to the Scinicidae and less confidently with the lacertiforms (Teiidae, Gymnophthalmidae, and Lacertidae). The family is relatively ancient and evolved before the separation of the southern supercontinent Gondwana and the separation of Madagascar from Africa in the middle Cretaceous epoch (80–100 million years ago).

Two well-defined subfamilies are recognized, and have often been treated as separate families within a superfamily— the Cordyliformes.

The first subfamily is Cordylinae, or girdled lizards. The head has four parietal scales and the nostril is enclosed in a single, or between only two, scales. Cordylines are restricted to southern and tropical Africa. Within cordylines, the flat lizards (Platysaurus, 16 species) are the basal stock and retain oviparity. Crag lizards (Pseudocordylus) and grass lizards (Chamaesaura) evolve from within girdled lizards (Cordylus), and to reflect this evolutionary relationship these genera have recently been transferred to Cordylus. This large genus now contains more than 40 species.

The second subfamily is Gerrhosaurinae, or plated lizards. The head has two parietal scales and the nostril is surrounded by three to four scales. Two genera are restricted to Madagascar and another three genera inhabit savanna and semiarid regions of Africa south of the Sahel. The desert plated lizard, previously included in a separate genus (Angolosaurus), is now transferred to Gerrhosaurus.

Physical characteristics

Girdled lizards are the most typical cordylines, with well-developed limbs and stout bodies covered with overlapping, spiny scales. The bodies of flat lizards, however, are covered with small, granular scales, although the legs may still have a few scattered, spiny scales. Scales on the belly and back are strengthened with bony elements (osteoderms). A longitudinal, expandable fold of granular scales runs along the flanks

to give flexibility (it is reduced in size in some genera). The head is usually triangular with large, symmetrical, bony head shields. The tongue has a simple notch and is covered in papillae. Femoral pores are conspicuous in males, and sometimes also in females. The tail can be shed and regenerated. In girdled lizards it is ringed with spiny scales and is not much longer than the head-body length. Plated lizards have much longer tails, ringed with elongate, rectangular scales.

Among cordylines, flat lizards are unmistakable. The body is very flat and covered with granular scales, while the legs often have scattered spiny scales. These depressed dandies are clothed in Jacobean splendor, the colors varying from species to species. They are most vivid on the belly, where their intensity is hidden from predators. Females and juveniles have black backs, usually attractively marked with three pale, longitudinal, dorsal stripes. Males grow slightly larger than females.

Even though they are not closely related, grass and snake lizards have evolved elongate bodies and long tails that allow them to move freely in long grass. They move with the speed and agility of snakes. The vestigial limbs are often reduced to minute spikes, and although they appear useless they give stability when the lizard is at rest. Their rustic colors camouflage them in dried grass.

Plated lizards (Gerrhosaurus) have stout bodies and well-developed limbs. The desert plated lizard (G. skoogi) is adapted for desert life. The spadelike snout, relatively short, conical tail, and cylindrical body allow it to dive into the loose sand of slip faces, while the long limbs and fringed toes allow it to run at lightning speed across wind-compacted sand. The dwarf plated lizard (Cordylosaurus subtessellatus) is a very small (to 6 in [15 cm]), brightly colored species restricted to the arid western regions of southern Africa. Plated snake lizards or seps (Tetradactylus, six species) show a progressive evolutionary transition from normal-limbed species to others that have become snakelike with vestigial limbs. Madagascan plated lizards (Tracheloptychus, two species, and Zonosaurus, 13 species) are more gracile and skinklike than their African cousins and have reduced body armor.

Distribution

The greatest diversity of girdled lizards, and their probable center of origin, is south of the Zambezi River, although a number of species extend into central and East Africa. Flat lizards have speciated explosively in Zimbabwe and adjacent areas, where 14 species (some with local races) occur. Two isolated species occur in the Northern Cape province of South Africa, one extending into southern Namibia. Grass and snake lizards are restricted mainly to southern Africa, although both have representatives in the savannas of central Africa. Plated lizards extend through the savannas of southern and central Africa, reaching Ethiopia in the north and Ghana in the west. Two genera also occur on Madagascar and have been introduced to a number of other Indian Ocean islands (e.g., Aldabra).

Habitat

Flat lizards live in rock outcrops in either savanna or rocky desert. Most girdled lizards occupy similar habitats, although a few live under dead tree bark or in tunnels in grassland. Grass lizards prefer short heath or grassland. Most plated lizards inhabit savanna or scrubland. However, one species is adapted to desert dunes, some Madagascan species inhabit forest floors, and another is semiaquatic and favors riverbanks. The snakelike seps forage in grassland or mountain heath-land. The dwarf plated lizards live among succulents and rocks from the Karoo of South Africa to Angola.

Behavior

Girdled lizards' thick scales with bony plates protect them from abrasion against rough rock. To evade predators, many species jam themselves into rock cracks by inflating the body and shortening and thickening the skull, which has an unusual hinged structure. Armadillo lizards (Cordylus cataphractus) are very social and form large groups (up to 43) that inhabit the

same rock crack. They are very wary and retreat at the first sign of danger. If caught in the open, like their namesakes, they bite their tail and roll into a tight ball. It makes it difficult for predators to swallow them.

The shape of flat lizards permits them to squeeze under thin rock flakes where they are safe from predators. Up to 12 individuals may squeeze into the same crack, although it is unusual to find adult males together during the breeding season. They are restricted to certain types of rock (e.g., granite, gneiss, and some sandstone), and are therefore found in isolated populations. Sociable, they form dense colonies. Prime territory on a rock face is defended by a dominant male during the breeding season. In confrontations, males circle each other and expose their brightly colored bellies by tilting sideways.

Snake and grass lizards hunt grasshoppers and other insects in grassland. They are diurnal, retreating at night into a grass tussock or beneath a stone. The vestigial limbs are minute, and are used for support when stationary and to assist small movements in long vegetation. The very long tail (up to three times the body length) is used for propulsion, rendering them almost impossible to catch when they "swim" through grass. When startled they also "spring" by flexing stiff coils against the ground. If grabbed, the tail is readily shed. However, regeneration is very rapid; it must be, as they are helpless without their tails.

Except for a few small Madagascan species that clamber on tree trunks, all plated lizards are terrestrial. They dig holes in loose sand around bushes or excavate leaf litter from large rock cracks or under boulders. When foraging they move slowly, often sliding down slopes on their smooth bellies. When basking they rest on the belly with the limbs flexed upward off the ground. The thick tail base is used for fat storage. Rarely common, they are shy and usually solitary, although the giant and desert plated lizards often form loose colonies. When disturbed they dash into bush clumps or to their retreats. In danger the desert plated lizards dive into loose sand, disappearing with a swimming motion. They can remain buried for up to 24 hours, sheltering from both danger and temperature extremes.

Feeding ecology and diet

Flat and girdled lizards are ambush predators that make short dashes to capture small invertebrates (flies, beetles, caterpillars, etc.). They also eat berries when seasonally available. The slow-moving plated lizards eat large insects, snails, etc. The larger species also eat leaves and berries, and will even eat small lizards and snakes if they can be caught. They are active foragers, and scrape away loose soil or leaf litter looking for hidden prey. Desert plated lizards forage at the base of dunes feeding on beetles, dry plant debris, grass seeds, and stems of the succulent Nara plant.

Reproductive biology

Girdled lizards are viviparous, giving birth to a few (one to six) large babies each year. Some live in diffuse colonies,

in which the males are territorial during the breeding season. Although they usually have drab coloration, adult males do have active femoral and glandular pores and appear to use chemical clues to signal status and territorial boundaries. Sexual maturity is reached in two to four years and they are long-lived (up to 25 years is known in captivity). In courtship male flat lizards present to females, raising their head and forebody to reveal the bright colors of the throat and chest. Unlike other cordylines, they are oviparous and lay only two eggs, usually in November to December. The relatively large, elongate eggs are 0.3–0.4 in (7–10 mm) wide, 0.7–0.9 in (17–22 mm) long, soft-shelled, and laid in deep cracks, usually in damp leaf mold. Numerous females may nest in the same crack. Grass lizards are also viviparous. Surprisingly for such thin, active lizards, they have relatively large litters (up to 12 young, each 6 in [15 cm] long). Birth may take two to three days, and the young often escape by wriggling from their mother's body.

All gerrhosaurines are oviparous, and lay a few soft-shelled eggs in moist sites. Little is known of the reproduction of seps or plated snake lizards. One species lays a small clutch of two to five eggs in midsummer in a live Anochetus faurei ant nest. Several females may use the same site. The eggs develop safely in the warm, protected ant nest and hatch between February and April; hatchlings measure 4.5–5.5 in (114–140 mm).

Conservation status

The IUCN lists five species as Vulnerable and another five as Lower Risk/Near Threatened. Because they live on isolated rocky outcrops, many girdled and flat lizards have very restricted distributions. Due to their bright colors and hardy nature, they are also popular in the international reptile pet trade. As a consequence many populations are threatened, and trade in girdled lizards (Cordylus) is therefore protected under CITES, Appendix II. Eastwood's seps (Tetradactylus east-woodae) is one of the few extinct African reptile species. It lived in montane grassland along the eastern escarpment of South Africa, but this is now all covered by pine plantations.

Significance to humans

The large colonies of colorful flat lizards are important tourist attractions at scenic sights in southern Africa (e.g., at World's View in the Matobo National Park, Zimbabwe, and Augrabies Falls in South Africa).

Species accounts

List of Species

Giant girdled lizard
Cape flat lizard
Madagascan plated lizard

Giant girdled lizard

Cordylus giganteus

subfamily

Cordylinae

taxonomy

Cordylus giganteus A. Smith, 1844, interior districts of southern Africa.

other common names

English: Sungazer; French: Cordyle géant; German: Riesengürtelschweif.

physical characteristics

Giant girdled lizards have very spiny scales, as well as four very large occipital spikes that adorn the back of their triangular head. The tail has whorls of very large spines. The body is yellow to dark brown, clouded with dark brown. Juveniles are more intensely marked, with irregular crossbars of red-brown on the back.

distribution

Restricted to the Highveld region of central South Africa.

habitat

They live in flat or gently sloping grassland, with deep soil for their burrows.

behavior

Found in diffuse colonies, they dig long burrows (up to 6 ft [1.8 m]) in deep soil. Usually only a single adult lives in a burrow, but it may be shared with juveniles. If a predator enters the burrow when the lizard is inside, the lizard backs along the tunnel toward the entrance, lashing its spiny tail from side to side in the face of the intruder. They often bask at the entrance to their burrow or on a nearby termite mound, staring at the sun—hence their common name. They are dormant during winter and rarely seen above ground from May to mid-August.

feeding ecology and diet

Sit-and-wait ambushers, they feed mainly on invertebrates (beetles, grasshoppers, millipedes, termites, and spiders), although they will take small vertebrates if the opportunity arises.

reproductive biology

One or two young, measuring up to 6 in (15 cm), are born from January to April, possibly only every two to three years.

conservation status

This species is listed as Vulnerable by the IUCN. Their numbers are declining due to habitat destruction by agriculture and, to a limited extent, because of illegal collecting for the pet trade.

significance to humans

Because it was familiar and conspicuous to the early settlers of South Africa, the giant girdled lizard was chosen as the national lizard, and its images have adorned postage stamps and conservation posters.

Cape flat lizard

Platysaurus capensis

subfamily

Cordylinae

taxonomy

Platysaurus capensis A. Smith, 1844, Great Namaqualand, Namibia.

other common names

None known.

physical characteristics

The cape flat lizard is a very flattened lizard. Females and juveniles have a dark brown back with three broad, cream stripes, a straw-colored tail, and a white belly with a central black patch. Sexually mature males are beautifully colored. The head and most of the body are Prussian blue, sometimes with numerous pale spots and the juvenile stripes may faintly persist. The rear of the body, hind limbs, and tail are red-brown. Beneath the throat is light blue, the chest dark blue, and the belly black-centered.

distribution

Namaqualand as far south as Garies, Northern Cape, South Africa, and extending into southern Namibia along the Fish River canyon.

habitat

Large granite outcrops in rocky desert.

behavior

These beautiful lizards are common on granite, but rarely form dense colonies. The males are shy and difficult to approach.

feeding ecology and diet

It is an ambush predator that sits motionless in the shade of a rock crack and makes a quick dash to collect small insects. Flowers and berries are also eaten in season.

reproductive biology

A small clutch of only two large, oval eggs are laid in moist soil beneath a sunny rock crack in November to December; a second clutch may be laid later in the summer.

conservation status

Not threatened. Some small colonies may be threatened by mining activities, but much of this lizard's rocky desert home is uninhabited.

significance to humans

None known.

Madagascan plated lizard

Zonosaurus madagascariensis

subfamily

Gerrhosaurinae

taxonomy

Zonosaurus madagascariensis Gray, 1831, Madagascar.

other common names

None known.

physical characteristics

A medium-sized plated lizard (up to 14 in [36 cm]) with an elongate, slightly flattened body with a prominent lateral fold running the length of the flank. The long tail is almost twice as long as the body. The ground color is brown, with two yellow lateral stripes that run from the eye to the base of the tail. The color of the flanks is variable, but is usually mottled with white and dark scales. The belly is grayish white, but may be reddish on the throat in some areas.

distribution

More common in eastern Madagascar, but also known in the west and south and on some offshore islands. It has also been introduced to Aldabra.

habitat

Normally found in dry, open landscapes, they adapt well to field edges and secondary thickets.

behavior

A solitary but common, terrestrial species that forages in sunwarmed clearings. It shelters in a small tunnel at the base of a bush, and may climb onto the base of trees.

feeding ecology and diet

They are active foragers that eat a wide variety of insects, as well as fruits and berries.

reproductive biology

A small clutch (up to five) of large, elongate eggs are laid in moist soil.

conservation status

Not threatened. Widespread and tolerant of agriculture, this species remains common throughout most of Madagascar.

significance to humans

None known.

Resources

Books

Branch, Bill. Field Guide to Snakes and Other Reptiles of Southern Africa. South Africa: Struik Publishers, 1998.

Glaw, Frank, and Miguel Vences. Field Guide to the Amphibians and Reptiles of Madagascar. 2nd edition. Privately printed, 1994.

Periodicals

Frost, Darrel, et al. "A Molecular Perspective on the Phylogeny of the Girdled Lizards (Cordylidae, Squamata)." American Museum Novitates 3310 (2001): 1–10.