Geckos and pygopods

(Gekkonidae)

Class Reptilia

Order Squamata

Suborder Lacertilia

Family Gekkonidae

Thumbnail description
Small to medium-size lizards, often drab in color and with stocky, flattened bodies and large heads (geckos) or elongate with no forelimbs and with hind limbs reduced to tiny flaps (pygopods)

Size
0.6–10.0 in (16–255 mm) in snout-vent length

Number of genera, species
116 genera; 1,109 species

Habitat
Desert, forest, savanna, and grassland

Conservation status
Extinct: 3 species; Extinct in the Wild: 1 species; Critically Endangered: 1 species; Endangered: 3 species; Vulnerable: 15 species; Lower Risk/Near Threatened: 8 species

Distribution
Worldwide in tropical, subtropical, and some warm temperate areas

Evolution and systematics

One of the earliest lizards to show some of the features of geckos is the late Jurassic Eichstaettisaurus from Germany. Although it was similar to modern geckos in general appearance, it lacked the derived features that characterize the living forms, and its true affinities remain the subject of controversy. The oldest definitive gecko represented in the fossil record is Hoburogecko suchanovi, which lived in Mongolia about 100 million years ago. Tertiary gecko fossils as well as geckos imbedded in amber have been recorded from numerous localities around the world, and many of them belong to living genera.

Geckos constitute the bulk of the Gekkota, the sister group of the Autarchoglossa and one of the three major lineages of lizards. Some researchers regard the xantusiids, dibamids, and amphisbaenids as allied to the geckos, but the evidence is equivocal. Geckos (including pygopods) are partitioned into 116 genera in four subfamilies: the Eublepharinae (22 species), Diplodactylinae (121 species), Gekkoninae (930 species), and Pygopodinae (36 species), each of which is sometimes treated as a separate family. Morphologic features and at least some DNA sequence evidence support the Eublepharinae as the sister group of the remaining geckos. The diplodactylines, which are restricted to Australia, New Caledonia, and New Zealand, are allied most closely to the pygopodines, which occur chiefly in Australia, with two species reaching New Guinea. Of the four subfamilies, Gekkoninae contains the greatest number of species and has, by far, the widest distribution, occurring throughout the tropics and subtropics worldwide. The origin of the major clades within the Gekkonidae may be linked to the breakup of the supercontinent of Pangea in the late Jurassic and the subsequent fragmentation of the southern continent of Gondwana during the Cretaceous and early Tertiary.

Physical characteristics

Most geckos are relatively small (1.2–3.5 in, or 30–90 mm) with short, somewhat flattened bodies; large heads; large eyes; and well-developed limbs. Eublepharines have movable eyelids, but they have been replaced by a transparent spectacle (eye cover) in other members of the subfamily. The smallest geckos are the sphaeros of the West Indies; the Jaragua sphaero (Sphaerodactylus ariasae) averages only 0.63 in (16 mm) in snout-vent length. At the other end of the spectrum is the New Caledonian giant gecko (Rhacodactylus leachianus), the largest living species at more than 10 in (250 mm). The recently extinct Delcourt's giant gecko (Hoplodactylus delcourti) of New Zealand, however, was much larger still at 14.6 in (370 mm) in snout-vent length.

The feet are one of the most striking and varying aspects of the morphologic characteristics of the gecko. Eublepharines and some gekkonines and diplodactylines have slender digits with well-developed claws, but many species have expanded pads on the base and or tips of the toes that permit adhesion to smooth surfaces. These pads may be distal (at the tips of the toes) and fan- (Ptyodactylus) or leaf-shaped (Phyllodactylus), or they may be basal (at the base of the toes) and arranged in single (Gekko) or divided (Hemidactylus) rows. The

first digit of the hands and feet may be reduced in size, but it is never lost entirely.

Pygopods have features that are an exception to the typical gecko body plan. In this lineage the forelimbs have been lost entirely, whereas the hind limbs are reduced to small flaps lying lateral to the vent. Pygopods also have smaller heads and much more elongate bodies (and especially tails) than other members of the family. Pygopods are covered with smooth, imbricating (overlapping) scales. Such scaling is extremely rare among geckos, which usually are covered with small granules, with or without larger keeled tubercles (enlarged scales with a raised ridge) intermixed.

Most geckos are drab in color, in keeping with their nocturnal habits. Browns and grays are the most common colors, and diffuse patterns of chevrons or crossbars characterize many species; in diurnal forms, such as the Malagasy day gecko (Phelsuma), bright greens, yellows, reds, and blues may be encountered. The males of many species of geckos possess a series of precloacal glands or femoral pores, or both, on the ventral surface of the groin and thighs.

Distribution

Geckos are chiefly tropical and subtropical in their distribution, but species range as far north as the southwestern United States, southern Europe, and southern Siberia. To the south, geckos reach Stewart Island in New Zealand and approach the southern tip of South America. Although they are most common at lower elevations, geckos are found up to 12,000 ft (3,700 m) in the Himalayas. Geckos also have reached most tropical and subtropical islands and, along with skinks, are often the only land reptiles on remote oceanic islands. Some species, such as the house gecko (Hemidactylus frenatus) and the mourning gecko (Lepidodactylus lugubris) have wide distributions, but most species are restricted to small geographic ranges. Many geckos are substrate-limited and prefer only particular types of rocks, trees, or soils. Gecko diversity is especially high in arid and semiarid habitats in Africa and Australia and in forested parts of Southeast Asia and Madagascar. Few species live in North America, Europe, or temperate Asia. Some geckos live commensally with humans and are transported easily. The Mediterranean gecko (Hemidactylus turcicus) has been introduced into many places in North America, and a colony survives as far north as Baltimore, Maryland.

Habitat

Geckos require egg-laying sites, adequate supplies of arthropod prey, and retreats that protect against temperature extremes and predators, all of which can be found in a diversity of habitats. In arid zones, geckos often occupy narrow rock crevices or else they burrow, creating shallow tunnels or occupying those of other animals in sandy soils. A few species, such as the web-footed gecko (Palmatogecko rangei), are specialists of dune faces. Some arid-zone geckos and pygopods live and forage in grass hummocks. Humid tropical forest habitats also are used widely by geckos, which may live on the trunks or branches or in the canopy of trees, under rotting logs, or on rocks along streams and rivers. In savannas and grasslands geckos are less numerous and often patchily distributed, using trees, rocks, or termite nests as shelter. A small, but conspicuous minority of geckos favor the walls of buildings or other manmade structures, where artificial lighting attracts insect prey.

Behavior

Most geckos are nocturnal and emerge from hiding in the early evening to forage and seek mates. Because they gain most of their heat via conduction from warm surfaces, their body temperatures drop as the night progresses, and activity may be limited to just a few hours at cooler times of the year. Diurnal geckos may have one or two peaks of activity during the day, often in the late morning and again in the mid-to late afternoon. Tropical species are active year-round, but in the north and south of the family's distribution, geckos remain inactive, deep in burrows or crevices, during cold periods. They rarely cease all activity, however, and can emerge to take advantage of warmer nights.

Many geckos are relatively solitary, though Bibron's gecko (Pachydactylus bibronii) and some other species can reach very high densities and may share retreat sites. These geckos have

reduced levels of aggression toward one another, but there is little evidence of a complex social structure. In the Indian golden gecko (Calodactylodes aureus), only the largest male in an area is brightly colored. If he is removed, the next largest male assumes this color and associated dominant status.

Many geckos, especially males, actively defend important resources, such as retreat sites and feeding areas. These geckos stave off rivals of their own and other species by vocalizing, using complex patterns of clicks and chirps. Geckos also use vocalizations, in combination with bites and defecation, to deter predators. Many geckos have cryptic coloration or outlineconcealing skin folds and flaps to avoid detection, and a few, such as the Namib day gecko (Rhoptropus afer), can outrun most predators. Tail autotomy, the ability to shed or drop the tail, is common among geckos. Threatened geckos lure predators to attack the tail, which continues to wriggle after it is shed, distracting the predator and allowing the animal to escape. The loss of the tail usually carries with it a significant energetic cost, but in the marbled gecko (Christinus marmoratus), tail loss has the immediate benefit of increased running speed. Certain geckos, mostly island species, also can shed large portions of their body skin if they are grasped by predators, and they can regrow skin over the large wounds. Members of two genera of diplodactyline geckos (Strophurus and Eurydactylodes) can ooze or squirt a sticky fluid from the tail that can entangle the mouth parts of such predators as spiders.

Feeding ecology and diet

Nearly all geckos survive on insectivorous diets. Most small species eat only arthropods, but some larger species take small vertebrate prey. Tokay geckos (Gekko gecko), for example, can

overpower and eat small snakes, lizards, and mammals as well as nestling birds. One species of New Caledonian gecko (Rhacodactylus auriculatus) has specialized fanglike teeth for piercing the bodies of other lizards. Burton's snake lizard (Lialis burtonis) has hinged teeth that permit it to feed on hard-bodied prey, such as small skinks, whose skins are reinforced by osteoderms (bony plates embedded in the skin). In New Zealand and on other islands, both diurnal and nocturnal geckos often supplement their diet with the fruits, nectar, or pollen of plants. In some cases, these lizards may play important roles as both pollinators and seed dispersers.

Geckos hunt using a combination of visual and chemical cues. Eublepharines and probably some other geckos forage widely and use chemical cues to locate prey. Most other species, however, are ambush predators, moving little and relying on vision to identify arthropod prey that come within striking range.

Reproductive biology

Males of some species attract females by calling. This reaches an extreme in the bell geckos (Ptenopus) of southern Africa, in which males participate in choruses. Individual males try to attract mates by calling from their burrow entrances, which serve as resonating chambers to amplify the sound. Less vocal geckos, such as leopard geckos (Eublepharis macularius), can identify members of the opposite sex by chemical cues, and many others identify mates visually at close range. Male geckos rub or lick females before mating and restrain them during copulation by biting them on the nape of the neck or the back. In the mourning gecko (Lepidodactylus lugubris) and a few other species, there are no males. Such unisexual species have arisen from the hybridization of two bisexual parental species and, once established, reproduce clonally by parthenogenesis.

Most geckos and all pygopods lay eggs. In gekkonine geckos the eggs are hard-shelled, but in the remaining subfamilies they are leathery. Females lay eggs in protected sites that often provide a high-humidity microclimate, such as on the axils of leaves, under bark, or in shallow nests in the soil. Desert geckos lay eggs in burrows or rock crevices or lay flattened, adherent eggs on vertical or overhanging rock surfaces. All geckos have fixed clutch sizes. Most species produce two young in a clutch, but a few groups of mostly smaller species produce a single egg at a time. Tropical species may produce several clutches a year, sometimes only during wetter periods, but those in cooler climates often have only a single clutch in a year.

Geckos typically abandon their eggs, and development takes one to six months, depending on temperature. In eublepharines and some gekkonines, the sex of the offspring is temperature-dependent. The average temperature experienced by developing embryos during the second trimester of development determines what sex the geckos will become, with higher temperatures yielding males and lower temperatures yielding females. Hatchling geckos slit their eggshells with paired egg teeth that are shed shortly after eclosion (hatching). The geckos of New Zealand and one species in neighboring New Caledonia are unique in being viviparous (live-bearing) and possessing a simple placenta. These species always produce twins, which may gestate for four to 14 months.

Conservation status

Population estimates exist for very few geckos, and the conservation status of most species is unknown. Many geckos live in desert areas that are affected little by humans or, like some tropical species, actually exploit human habitations for their own use. Many island-dwelling geckos with restricted distributions, however, are imperiled by habitat destruction, particularly deforestation, and by the introduction of rats, cats, and other predatory mammals. Among the only geckos believed to have become extinct in historical times are the giant gecko of Round Island in the Mascarenes (Phelsuma edwardnewtoni) and the largest gecko that ever lived, Delcourt's

giant gecko from New Zealand. In each case, introduced predators probably were to blame. Geckos of the genus Phelsuma, which are especially brightly colored and attractive, are all internationally protected as CITES Appendix II species because they are popularly sold in the pet trade.

Significance to humans

Large geckos, such as the voracious gecko (Gehyra vorax) of Fiji, once were hunted for food, but most modern human consumption of geckos is for medicinal purposes. Tokay geckos and other species are sold dried or pickled in wine or spirits to increase vitality and cure kidney ailments in China and parts of Southeast Asia. In much of the tropics house geckos are welcome as predators on insect pests, and in Europe and North America geckos are favorites of herpetoculturalists. All geckos are harmless, but their mysterious nocturnal habits, large eyes, and climbing abilities have been interpreted as signs of evil; in some cultures they are regarded incorrectly as venomous to the touch.

Species accounts

List of Species

Western banded gecko

Coleonyx variegatus

subfamily

Eublepharinae

taxonomy

Stenodactylus variegatus Baird, 1859, Rio Grande and Gila Valleys, Arizona, United States. Five subspecies are recognized.

other common names

French: Coleonyx varié; German: Gebänderter Krallengecko; Spanish: Salamanquesa de franjas.

physical characteristics

This species reaches 3 in (75 mm) in snout-vent length. The body is covered in fine granules; the digits are slender, without pads; and the tail is constricted at the base. These geckos have movable eyelids and vertical pupils. They are pink to pale yellow, with brown bands, blotches, or irregular markings.

distribution

The subspecies Coleonyx variegatus variegatus lives in southeastern California, southwestern Nevada, and western Arizona in the United States and the northern Gulf of California, Mexico. C. v. abbotti occurs in southwestern California in the United States and northern Baja California, Mexico. C. v. bogerti lives in southeastern Arizona and southwestern New Mexico in the United States and northern Sonora, Mexico. C. v. sonoriensis inhabits western Sonora and southern Baja California, Mexico. C. v. utahensis occurs in Utah, southern Nevada, and northwestern Arizona.

habitat

The species inhabits rocky desert and semidesert.

behavior

These geckos are nocturnal; several individuals may aggregate in a single burrow.

feeding ecology and diet

The species is a generalist arthropod feeder. Energy is stored as fat in the tail.

reproductive biology

The female lays two leathery-shelled eggs per clutch, usually between May and September.

conservation status

Although not listed by the IUCN, the San Diego banded gecko (C. v. abbotti) is of special concern in California.

significance to humans

None known.

New Caledonian giant gecko

Rhacodactylus leachianus

subfamily

Diplodactylinae

taxonomy

Ascalabotes leachianus Cuvier, 1829, type locality unknown.

other common names

English: Leach's giant gecko; French: gecko géant de Leach, caméléon géant; German: Neukaledonischer Riesengecko.

physical characteristics

The species grows to 10 in (255 mm) in snout-vent length and is considered the largest living gecko. It is heavy-bodied, with extensive skin folds on the flanks and legs and partially webbed digits. The head is elongate; the feet are large, with broad, undivided pads; and the tail is very short. These geckos are brownish, greenish, or gray with darker punctuations (speckles) or reticulations (net-like patterns) or with white or pinkish bars on the flanks.

distribution

The species is native to New Caledonia.

habitat

These geckos inhabit humid forest.

behavior

The geckos are nocturnal, spending daylight hours motionless on tree trunks or branches. They make a variety of croaks, growls, and whistles.

feeding ecology and diet

The species is insectivorous (insect-eating) and frugivorous (fruit-eating). It may eat fruits exclusively at certain times of year and also prey on nestling birds and lizards.

reproductive biology

Clutches of two large (up to 1.6 in, or 40 mm) leathery-shelled eggs are laid in shallow nests in the ground. Sex determination may be temperature-dependent.

conservation status

Not threatened. The species is widespread on the mainland and offshore islands, but deforestation and illegal collecting for the pet trade are causes for concern.

significance to humans

This is a highly desirable species in the herpetocultural trade.

Tokay gecko

Gekko gecko

subfamily

Gekkoninae

taxonomy

Lacerta gecko Linnaeus, 1758, Java, Indonesia. Two subspecies are recognized, but some populations currently included in Gekko gecko gecko probably are distinct.

other common names

French: Tokay; German: Tokeh.

physical characteristics

The species grows to 7.1 in (180 mm) in snout-vent length. The body is flattened, the head is broad, and the pupils are vertical. Precloacal glands are present in males. The scales are granular, and there are several rows of enlarged tubercles. The toes are dilated broadly, with large, undivided pads. The species has a bluish or grayish body with both orange or red markings as well as white ones.

distribution

G. g. gecko occurs in tropical Asia from northeastern India to eastern Indonesia. It was introduced into southern Florida in the United States. G. g. azhari lives in Bangladesh.

habitat

These geckos inhabit trees in tropical forests and disturbed areas (any areas affected by humans); they also live on buildings.

behavior

The species is nocturnal and highly aggressive. Individuals gape, lunge, and bite both other geckos and predators. They are highly vocal in both defensive and courtship situations.

feeding ecology and diet

The diet includes insects and a variety of small vertebrates.

reproductive biology

Several clutches of two hard-shelled eggs are attached firmly to substrate and, at least in captivity, defended.

conservation status

Not threatened.

significance to humans

The species is used in traditional Asian medicine and traded commercially as pets.

Yellow-headed gecko

Gonatodes albogularis

subfamily

Gekkoninae

taxonomy

Gymnodactylus albogularis Duméril and Bibron, 1836, Martinique and Cuba. Four subspecies are recognized.

other common names

French: Gonatode à gorge blanche; German: Weisskehlgecko; Spanish: Geco cabeza-amarilla

physical characteristics

The species reaches 1.3–1.8 in (32–45 mm) in snout-vent length. The dorsal scales are granular, the pupils are round, and the digits are narrow, without enlarged toe pads. Males are gray to black with a yellow head, and females are gray with dark brown mottling.

distribution

Gonatodes albogularis albogularis exists in Aruba, Curaçao, eastern Colombia, and northwestern Venezuela. G. a. bodinii lives in the Archipelago de Los Monjes, Venezuela. G. a. fuscus inhabits Cuba and Central America to northwestern Colombia; it was introduced into southern Florida. G. a. notatus occurs in Hispaniola, Jamaica.

habitat

The geckos live under debris and on trees in a variety of habitats. They also occur on buildings and in piles of lumber or trash.

behavior

The species is diurnal and basks in partly exposed positions on houses or trees.

feeding ecology and diet

The diet consists of small arthropods.

reproductive biology

The female lays several clutches of single hard-shelled eggs a year.

conservation status

Not threatened.

significance to humans

None known.

House gecko

Hemidactylus frenatus

subfamily

Gekkoninae

taxonomy

Hemidactylus frenatus Duméril and Bibron, 1836, Java, Indonesia.

other common names

English: Half-toed geckos; French: Margouillat; German: Asiatischer Halbzehengecko.

physical characteristics

The species grows to 2.6 in (65 mm) in snout-vent length. The body is flattened. The toe pads are divided, and the first digit is much smaller than the others. The tail has enlarged ventral plates and a denticulate margin. These geckos are grayish, pinkish, or pale brown with darker flecks.

distribution

The species exists in Southeast Asia and the Indo-Australian archipelago, the Philippines, Taiwan, and much of Micronesia, Melanesia, and Polynesia. It was introduced into tropical Australia, eastern Africa, Mexico, the United States and elsewhere.

habitat

These geckos live among many types of vegetation but often are found around human habitations.

behavior

Males may be aggressive, especially in areas of high density near abundant food sources. They have complex multiple click vocalizations.

feeding ecology and diet

The species is a generalist insectivore, occasionally eating smaller lizards.

reproductive biology

Females lay clutches of hard-shelled eggs throughout the year. There is an incubation period is 45–71 days. The female is capable of sperm storage.

conservation status

Not threatened. This species may cause declines in native geckos where it is introduced.

significance to humans

This commensal species is found frequently in and around houses and other manmade structures.

Web-footed gecko

Palmatogecko rangei

subfamily

Gekkoninae

taxonomy

Palmatogecko rangei Andersson, 1908, Lüderitz, Namibia

other common names

French: Gecko du désert; German: Schwimmfußgecko.

physical characteristics

This species usually is 2.4–2.6 in (60–65 mm) in snout-vent length, with a maximum of 3.2 in (78 mm). The body is elongate and cylindrical, with slender legs terminating in broad webbed feet. The skin is translucent and pinkish with brown markings on top and bright white below.

distribution

The species is distributed through western Namibia and adjacent northwestern South Africa and western Angola.

habitat

These geckos inhabit the Namib Desert dunes.

behavior

This species is nocturnal and retreats by day into burrows up to 20 in (50 cm) long, excavated in windward dune faces using webbed feet. It assumes a stiff-legged posture when it is alarmed. Males attack and bite to defend the area around burrows.

feeding ecology and diet

This gecko preys on dune-dwelling spiders and beetles. All water is obtained from condensed fog or from prey.

reproductive biology

The species breeds in spring. Females lay two calcareous (hard-shelled) eggs, 0.8 × 0.4 in (21 × 10 mm), in burrows in the sand in summer (November to March). Incubation lasts about 90 days.

conservation status

The species is widespread and common in most of its range in Namibia and probably in Angola. A small South African population is threatened by diamond-mining operations.

significance to humans

None known.

Madagascar day gecko

Phelsuma madagascariensis

subfamily

Gekkoninae

taxonomy

Gecko madagascariensis Gray, 1831, Madagascar. The nominate form (the first subspecies to be named) and three additional subspecies—Phelsuma madagascariensis boehmei, P. m. grandis, and P. m. kochi—are all from Madagascar.

other common names

French: Phelsume de Madagascar; German: Madagassischer Taggecko.

physical characteristics

This species grows to 3.9–5.1 in (100–130 mm) in snout-vent length. The body is heavy and the tail thick. The toes have pads that are broadened distally, with a greatly reduced first digit on each foot. The scales are small and granular, and the pupils are circular. Males have precloacal glands. These geckos are bright green with red markings on the snout, head, and back.

distribution

The species ranges across northern and eastern Madagascar.

habitat

These arboreal geckos are found on trees in disturbed areas and in primary forest; they also are found on houses.

behavior

These geckos are diurnal and may congregate in high-density populations. Males maintain territories.

feeding ecology and diet

This is a generalist insectivore, but it also eats fruit or nectar, if available.

reproductive biology

Several clutches of one or two hard-shelled eggs are laid every four to six weeks during the summer or early fall (November to May). The incubation period is about two months.

conservation status

Not threatened. CITES regulates international trade.

significance to humans

This species is common in the herpetocultural trade. It breeds very well in captivity and can occur around human dwellings.

Common plate-tailed gecko

Teratoscincus scincus

subfamily

Gekkoninae

taxonomy

Stenodactylus scincus Schlegel, 1858, I-li River, Kazakhstan.

other common names

English: Frog-eyed gecko, wonder gecko; German: Wundergecko.

physical characteristics

This species reaches 4.6 in (116 mm) in snout-vent length. The head is large, with prominent eyes. The digits are straight, without pads. The body is covered with large cycloid, imbricate scales (which is uncommon for geckos) extending along the dorsum of the tail. There are no precloacal glands. The color and pattern of these geckos vary, but they usually have brown, orange, or bluish stripes or bands on a whitish, yellow, or gray background.

distribution

Teratoscincus scincus scincus lives in southern Kazakhstan, Uzbekistan, Turkmenistan, Tadzhikistan, Kyrgyzistan, and northern Afghanistan. T. s. keyserlingii occurs in eastern Iran, southern Afghanistan, western Pakistan, the United Arab Emirates, and Qatar. T. s. rustamovi exists in the Fergana Valley of Uzbekistan and Tadzhikistan.

habitat

The habitat is sandy arid and semiarid areas.

behavior

This species is nocturnal and burrowing. The enlarged scales of the tail can be rubbed together to create a buzzing noise that may deter predators. The fragile skin is damaged easily and can be shed to escape predators.

feeding ecology and diet

This species is a generalist insectivore.

reproductive biology

Females lay clutches of two hard-shelled eggs.

conservation status

Not threatened.

significance to humans

These geckos are traded commercially as pets.

Burton's snake lizard

Lialis burtonis

subfamily

Pygopodinae

taxonomy

Lialis burtonis Gray, 1834, Round Hill Fauna Reserve, New South Wales, Australia.

other common names

English: Burton's legless lizard; French: Lialis de Burton; German: Spitzkopf-Flossenfuß.

physical characteristics

The species reaches 10 in (250 mm) in snout-vent length. It is elongate, with no forelimbs and with hind limbs reduced to small flaps. The tail is longer than the body. The head is long, with a very elongate snout, and the pupils are vertical. It is brown or gray, with or without a pattern of regular spots or stripes.

distribution

The species ranges across Australia and southeastern New Guinea.

habitat

The geckos live in terrestrial habitats, from deserts to humid forest.

behavior

They are active day or night.

feeding ecology and diet

The species feeds on lizards, chiefly small skinks.

reproductive biology

Mating occurs in the spring, and females lay two elongate, leathery-shelled eggs in summer.

conservation status

The species is widespread and common throughout most of its range.

significance to humans

None known.

Resources

Books

Greer, A. E. The Biology and Evolution of Australian Lizards. Chipping Norton, Australia: Surrey Beatty and Sons, 1989.

Rösler, H. Geckos der Welt, alle Gattungen. Leipzig: Urania-Verlag, 1995.

Szczerbak, Nicolai N., and Michael L. Golubev. Gecko Fauna of the USSR and Contiguous Regions. Ithaca, NY: Society for the Study of Amphibians and Reptiles, 1996.

Periodicals

Bauer, A. M., and I. Das. "A Review of the Gekkonid Genus Calodactylodes (Reptilia: Squamata) from India and Sri Lanka." Journal of South Asian Natural History 5, no. 1 (2000): 25–35.

Bauer, A. M., and A. P. Russell. "Hoplodactylus delcourti n. sp. (Reptilia: Gekkonidae), the Largest Known Gecko." New Zealand Journal of Zoology 13, no. 1 (1986): 141–148.

——. "The Evolutionary Significance of Regional Integumentary Loss in Island Geckos: A Complement to Caudal Autotomy." Ethology, Ecology, and Evolution 4, no. 4 (1992): 343–358.

Cooper, W. E., Jr. "Prey Chemical Discrimination and Foraging Mode in Gekkonoid Lizards." Herpetological Monographs 9 (1995): 120–129.

Daniels, C. B. "Running: An Escape Strategy Enhanced by Autotomy." Herpetologica 39, no. 2 (1983): 162–165.

Frankenberg, E., and D. L. Marcellini. "Comparative Analysis of the Male Multiple Click Calls of Colonizing House Geckos Hemidactylus turcicus from the Southern U.S.A. and Israel and Hemidactylus frenatus." Israel Journal of Zoology 37, no. 2 (1990): 107–118.

Girling, J. E., A. Cree, and L. J. Guillette Jr. "Oviductal Structure in a Viviparous New Zealand Gecko, Hoplodactylus maculatus." Journal of Morphology 234, no. 1 (1997): 51–68.

Haacke, W. D. "The Burrowing Geckos of Southern Africa, 1. (Reptilia: Gekkonidae)." Annals of the Transvaal Museum 29, no. 12 (1975): 197–243.

Hedges, S. B., and R. Thomas. "At the Lower Size Limit in Amniotes: A New Diminutive Lizard from the West Indies." Caribbean Journal of Science 37, no. 3–4 (2001): 168–173.

Ineich, I. "La Parthénogenèse chez les Gekkonidae (Reptilia, Lacertilia): Origine et Evolution." Bull. Soc. Zool. France 117, no. 3 (1992): 253–266.

Kluge, A. G. "Cladistic Relationships in the Gekkonoidea (Squamata, Sauria)." Miscellaneous Publications, Museum of Zoology, University of Michigan 173 (1987): i–iv, 1–54.

——. "Gekkotan Lizard Taxonomy." Hamadryad 26 (2001): 1–209.

Patchell, F. C., and R. Shine. "Food Habits and Reproductive Biology of the Australian Legless Lizards (Pygopodidae)." Copeia 1986, no. 1 (1986): 30–39.

Petren, K., D. T. Bolger, and T. J. Case. "Mechanisms in the Competitive Success of an Invading Sexual Gecko over an Asexual Native." Science 259, no. 5093 (1993): 354–358.

Russell, A. P. "A Contribution to the Functional Analysis of the Foot of the Tokay, Gekko gecko (Reptilia: Gekkonidae)." Journal of Zoology London 176, no. 3 (1975): 437–476.

Werner, Y. L. "Observations on Eggs of Eublepharid Lizards, with Comments on the Evolution of the Gekkonoidea." Zool. Meded. 47, no. 17 (1972): 211–224, pl. I.

Whitaker, A. H. "The Roles of Lizards in New Zealand Plant Reproductive Strategies." New Zealand Journal of Botany 25, no. 2 (1987): 315–328.

Organizations

Global Gecko Association. 4920 Chester Street, Spencer, Oklahoma 73084-2560 USA. Web site: <http://www.gekkota.com>

Aaron Matthew Bauer, PhD