Lacertidae

(vertebrate zoology) A family of reptiles in the suborder Sauria, including all typical lizards, characterized by movable eyelids, a fused lower jaw, homodont dentition, and epidermal scales.

(Lacertidae)

Class: Reptilia

Order: Squamata

Suborder: Sauria

Family: Lacertidae

Thumbnail description
Small- to medium-sized diurnal, heliothermic, terrestrial lizards, all with well-developed legs and a tail usually much longer than the body

Size
Usually less than 8 in (20 cm), maximum around 20 in (50 cm)

Number of genera, species
28 genera; 225+ species

Habitat
Varied; most abundant in scrublands and desert, but also entering forest and montane grassland

Conservation status
Critically Endangered: 1 species; Endangered: 1 species; Vulnerable: 5 species

Distribution
Old World, throughout Africa, sub-Arctic Eurasia, and the northern East Indies

Evolution and systematics

Lacertid lizards are the sister groups of teioids (teiids and relatives of the New World). Together they form the Lacertiformes. Molecular studies have allowed the recent recognition of three subfamilies, although the relationships of a number of genera (e.g., Takydromus) remain unresolved. The most primitive subfamily is the Gallotiinae, which comprises the giant lizards of the Canary Islands and the smaller, but closely related Psammodromas from Iberia and adjacent North Africa. They share a suite of unusual, but non-unique features, as well as the strange ability to squeak. The Eremiainae includes many genera endemic to the Ethiopian region. The basal genera occur in tropical forests (e.g., Holaspis, Gastropholis, and Poromera) or montane habitats (e.g., Adolfus and Tropidosaura), with a progression of more specialized genera showing increasing adaptation to arid habitats (e.g., Ichnotropis, Heliobolus, Meroles, Pedioplanis, Ophisops, Mesalina, and Acanthodactylus). The remaining subfamily, Lacertinae, includes the typical lacertids of Eurasia. The relationships and composition of many of the genera in the subfamily remain in question. The large genus Lacerta has long been paraphyletic but has been increasingly subdivided in recent years, with the creation of a number of genera and subgenera, e.g., Omanosaura, Timon, Darevskia, Caucasilacerta, Parvalacerta, and so on.

Lacertids are believed to have arisen in Eurasia and invaded Africa and the Ethiopian region, where they evolved more xeric forms (adapted to arid conditions). One or more derivatives then re-entered the dry areas of Eurasia. The family has a long but fragmentary fossil history, extending back at least as far as the Palaeocene. Fragments of a recently described 120 million-year-old fossil lizard in amber from the Lower Cretaceous of Lebanon shows that common external features of lacertids and other autarchoglossan lizards had already evolved.

Physical characteristics

Lacertids are conservative in morphology, and no species have lost limbs, ears, or eyes. They are small- to medium-sized with slender bodies, well-developed limbs, and a long tail that in oriental grass lizards (Takydromus) may be nearly five times as long as the head and body. The dorsal scales are usually small, smooth, and granular (although in some genera they are large, rough, and overlapping). The belly scales are always large and quadrangular and almost always arranged in distinct longitudinal and transverse rows. The head is covered with large, symmetrical scales that have osteoderms, and most species have a pineal "eye" on the top of the head. The tongue is quite deeply notched. A skin-fold "collar" of enlarged scales on the neck is also usually present. In the skull the upper temporal arches are completely ossified, and the pterygoid and palatine bones are paired and lie close together anteriorly. The pterygoids often bear a group of palatal teeth. The dentition of the jaws is pleurodont (the teeth attached to the sides of the jawbone). Femoral pores are usually present in both sexes. The tail has whorls of keeled scales, which may be spiny; the tail is easily shed but can be regenerated. A complex armature supports the hemipenes in the Eremiainae.

Distribution

This family occurs throughout Africa and most of Eurasia. A few species occur on some off-shore islands, including the British Isles, the Canaries, Madeira, many Mediterranean islands, Socotra, Sri Lanka, and many islands of the Sunda Shelf. They are absent from Madagascar, however. They are the only lizards to enter the Arctic Circle.

Habitat

Members of this family are found from tundra and high montane grasslands through heath, Mediterranean vegetation, tropical forests, semi-arid scrublands, and true desert.

Behavior

Most species are active terrestrial or rock-living species, while a few others are arboreal. All are diurnal heliotherms. The exceptionally long tails of Asian grass lizards are prehensile to allow them to climb in vegetation. Of the many desert-living species, the most superbly adapted is the shovel-snouted lizard (Meroles anchietae) of the Namib Desert. It has large hindlimbs with fringed toes to help it run quickly over loose sand, and an aptly named snout that allows it to dive under the sand to escape predators and to sleep in cooler, deeper sand. Hatchlings of the Kalahari sand lizard (Heliobolus lugubris) are boldly marked in black and white and walk with a stiff-legged gait. They mimic the noxious oogpister ("eye squirter") beetle (Anthia), but when adult they become colored in cryptic tans and brown.

When attacked, lacertids can discard their tail. From the sixth vertebrae backwards, every tail bone has a special plane of weakness through its body. There are corresponding weak points in the surrounding connective tissue and musculature. If the tail is held, circular muscles at that position contract strongly, the tissues break, and the tip of the tail falls off. The discarded fragment continues to twist violently to attract the attention of the attacker while the tailless lizard escapes. The shortened tail can regrow, but it lacks bone and is supported only by a central rod of cartilage.

Feeding ecology and diet

Lacertids are active, diurnal lizards that hunt insects in open situations. A few are sit-and-wait ambush predators, usually capturing their prey with a quick dash from shaded cover. All are primarily insectivores, although some are also partial herbivores, eating dried seeds or fruit. The giant lizards (Gallotia) of the Canary Islands are almost entirely vegetarian, at least as adults.

Reproductive biology

The males of many species are brightly colored, with dominant males developing bright breeding colors. When defending its territory, the lizard displays by turning broadside, lifting its head, and expanding its throat. The flanks also flatten so as to present the most massive, threatening appearance. If the threat display does not deter a rival, an attack follows. The combatants bite each other and shake, but wounds are seldom serious because the head is well-armored.

With the exception of a few European species, all lacertids are oviparous, which is surprising as many live in temperate and montane environments where viviparity could be expected to evolve. Most lay small clutches (usually fewer than 10) of soft-shelled eggs in a small chamber dug in moist soil, often beneath a sun-warmed stone. As usual in lizards, the larger species lay more eggs, and in the eyed lizard (Lacerta lepida) this may be up to 20. There is no brood-care behavior. The viviparous lizard of northern Europe (Lacerta vivipara) is one of the few lacertids to give birth to live babies. A small brood of four to 11 young is born from late July to early October after a three to four month gestation. Seven Caucasian lacertids of the genus Darevskia are all-female species. They reproduce by parthenogenesis and result from inter-specific hybridization.

Over much of the savannas of the northern part of southern Africa, the Cape rough-scaled lizard (Ichnotropis capensis) and common rough-scaled lizard (I. squamulosa) live together. It is a simple rule in ecology that two species do not inhabit the same niche, as they would compete for the same resources. However, adult and juvenile lizards do not usually compete for the same food, and even if they eat the same species they take different size classes. The two rough-scaled lizards grow to maturity, mate, and lay their eggs within a year, and after reproducing die. Incubation of the eggs takes about two months. During any sixth-month period, one species is represented by adults that mate and lay eggs. At this time the other species' eggs are hatching, and the adults have died after reproducing. There is therefore no competition for food between the adults of one species and the hatchlings of the other species. As these hatchlings grow to maturity, the adults of the first species die, while within the ground their eggs develop. The two "annual" rough-scaled lizards have therefore evolved an elegant rotating solution to living together that minimizes competition.

Conservation status

Simony's giant lizard (Gallotia simonyi) of the Canary Islands was for many years considered extinct, until a small population was discovered in 1975 on a few inaccessible cliffs on El Hierro. It occurs in low numbers and is categorized as Critically Endangered by the IUCN. The Gomeran giant lizard (G. gomerana) was only known from sub-fossil material until a very small population of live lizards was discovered in 2001, again on inaccessible sea cliffs. It appears to be even rarer than Simony's giant lizard and, while not yet listed by the IUCN, is one of the most endangered reptiles in the world. Both species are threatened by the introduction of predators such as cats and rats to the islands. Clark's lacerta (Darevskia clarkorum), which is listed as Endangered, is restricted to the Black Sea region. Five other lacertids are considered Vulnerable in the IUCN Red List 2000, while over 30 lacertids are included on the Bern Convention on Conservation of European Wildlife.

Significance to humans

Few lacertids grow big enough to eat, although the giant lizards of the Canary Islands were eaten by the early settlers.

Species accounts

Resources

Böhme, W., ed. Handbuch der Reptilien und Amphibien Europas. 2 vols. Wiesbaden, Germany: AULA Verlag, 1984–1986.

Branch, B. Field Guide to the Snakes and Other Reptiles of Southern Africa. Struik Publishers, 1998.

Valakos, E.D., W. Böhme, V. Perez-Mellado, and P. Maragou, eds. Lacertids of the Mediterranean Region: A Biological Approach. Athens, Greece: Hellenic Zoological Society, 1993.

Arnold, E. N. "Towards a Phylogeny and Biogeography of the Lacertidae: Relationships Within an Old-World Family of Lizards Derived from Morphology." Bulletin of the British Museum of Natural History, Zoology 55 (1989): 209–257. ——. "Interrelationships and Evolution of the East Asian Grass Lizards, Takydromus (Squamata: Lacertidae)." Zoological Journal of the Linnean Society 119 (1997): 267–296.

Harris, D. J., E. N. Arnold, and R. H. Thomas. "Relationships of Lacertid Lizards (Reptilia: Lacertidae) Estimated from Mitochondrial DNA Sequences and Morphology." Proceedings of the Royal Society, London 265 (1998): 1930–1948.

[Article by: Bill Branch, PhD]

The noun has one meaning:

Meaning #1: Old World lizards
  Synonym: family Lacertidae

Lacertidae
Podarcis hispanica
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Reptilia Order: Squamata Family: Lacertidae Oppel, 1811
Genera
Many, see text.

Terminology and scalation of lacertids

Lacertidae is the family of the wall lizards, or true lizards, which are native to Europe, Africa, and Asia. The group includes the genus Lacerta, which contains some of the most commonly seen lizard species in Europe.

Contents 1 Habitat 2 Appearance and biology 3 Classification 4 External links 5 References

Habitat

The European and Mediterranean species live mainly in forest and scrub habitats.^[1] Eremias and Ophisops species replace these in the grassland and desert habitats of Asia. African species usually live in rocky, arid areas. Holaspis is one of the few arboreal lacertids, and its single species, Holaspis guentheri, is a glider (although apparently a poor one), using its broad tail and flattened body as an aerofoil.^[2]

Appearance and biology

Lacertids are small or medium-sized lizards. Most species are less than 9 cm long, excluding the tail, although the largest living species, Gallotia stehlini, reaches 46 cm, and some extinct forms were larger still. They are primarily insectivorous.^[1] An exception is Meroles anchietae, one of the few wall lizards that regularly eats seeds – an appropriate food for a lizard of the harsh Namib Desert.

Lacertids are remarkably similar in form, with slender bodies and long tails, but have highly varied patterns and colours, even within the same species. Their scales are large on the head, which often also has osteoderms, small and granular on the back, and rectangular on the underside. Most species are sexually dimorphic, with the males and females having different patterns.^[1]

At least eight species are parthenogenetic^{[citation needed]}, and three species give birth to live young, including the viviparous lizard, Zootoca vivipara.^[1]

Classification

Family Lacertidae

Subfamily Gallotiinae
	Genus Gallotia	Genus Psammodromus
Subfamily Lacertinae
	Genus Acanthodactylus Genus Adolfus Genus Algyroides Genus Anatololacerta Genus Atlantolacerta Genus Australolacerta Genus Dalmatolacerta Genus Darevskia Genus Dinarolacerta Genus Eremias Genus Gastropholis Genus Heliobolus Genus Hellenolacerta Genus Holaspis Genus Iberolacerta Genus Ichnotropis Genus Iranolacerta	Genus Lacerta Genus Latastia Genus Meroles Genus Mesalina Genus Nucras Genus Ophisops Genus Parvilacerta Genus Pedioplanis Genus Philochortus Genus Phoenicolacerta Genus Podarcis Genus Poromera Genus Pseuderemias Genus Takydromus Genus Timon Genus Tropidosaura Genus Zootoca

External links

• Family lacertidae

References

Wikispecies has information related to: Lacertidae

Wikimedia Commons has media related to: Lacertidae

1. ^ ^{a b c d} Bauer, Aaron M. (1998). Cogger, H.G. & Zweifel, R.G.. ed. Encyclopedia of Reptiles and Amphibians. San Diego: Academic Press. pp. 163–165. ISBN 0-12-178560-2. 
2. ^ Zug et al. 2001^{[broken citation]}

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