''Underwoodisaurus'' is a small

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of Australian lizards in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Carphodactylidae The Carphodactylidae, informally known as the southern padless geckos, are a family of geckos, lizards in the infraorder Gekkota. The family consists of 32 described species in 7 genera, all of which are endemic to Australia. They belong to the s ...

. Member

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

are commonly known as thick-tailed geckos, along with the species '' Uvidicolus sphyrurus''.

Etymology

The generic name, ''Underwoodisaurus'', is in honour of British herpetologist Garth Leon Underwood.Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. . (''Underwoodisaurus'', p. 270).

Taxonomy

The genus ''Underwoodisaurus'' has a complex taxonomic history, but the currently accepted taxonomic concept follows & (2011), with a second species subsequently recognised by & (2011). Reptile systematists nowadays recognise a distinct

, for this and some related genera.

Species

There are two species which are recognised as being valid: *''

Underwoodisaurus milii ''Underwoodisaurus milii'' is a species of gecko, a lizard in the family Carphodactylidae. The species is commonly known as the thick-tailed or barking gecko, referring to its distinctive plump tail and sharp, barking defensive call. The genus i ...

'' (, 1825) – thick-tailed gecko *'' Underwoodisaurus seorsus'' & , 2011 ''

Nota bene (, or ; plural form ) is a Latin phrase meaning "note well". It is often abbreviated as NB, n.b., or with the ligature and first appeared in English writing . In Modern English, it is used, particularly in legal papers, to draw the atten ...

'': A

binomial authority In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

in parentheses indicates that the species was originally described in a genus other than ''Underwoodisaurus''. The species '' Uvidicolus sphyrurus'' is sometimes placed in the genus ''Underwoodisaurus''.

Description

Adults of some species of ''Underwoodisaurus'' can reach a snout-to-vent length (SVL) of . Preanal pores are absent. The feet are generally "bird-like" with long slender digits, and the tail is carrot-shaped. The underside of the body is white, and the

dorsal surface Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ...

ranges from dark purplish-black through reddish-brown to pale fawn, with small white, yellow and black spots in patterns. A thick tail is generally a sign of good health, although lack of thickness may indicate recent egg-laying.

Geographic range and

The genus ''Underwoodisaurus'' is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to Australia. These geckoes are found in a range of

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s including wet coastal heathlands, wet sclerophyll forests, arid scrubland, rocky outcrops and stony hills in eucalypt woodland.

Ecology

Thick-tailed geckos shelter under

leaf litter Plant litter (also leaf litter, tree litter, soil litter, litterfall or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that have fallen to the ground. This detritus or dead organic material and its constituent ...

, around the bases of trees in loose bark, and in crevices. They emerge in the evenings to hunt in open areas for crickets, cockroaches and huntsman spiders. They eat once every 3–4 days. When they see prey they will stare at it and wag their tails, then pounce. When alarmed, the thick-tailed gecko will make a barking sound or hiss. They will also raise their backs. One main predator is snakes.

Reproduction

Thick-tailed geckos lay up to 2 eggs and up to 10 clutches per year. The first clutch of eggs is usually infertile. When the female is

gravid In biology and human medicine, gravidity and parity are the number of times a woman is or has been pregnant (gravidity) and carried the pregnancies to a viable gestational age (parity). These terms are usually coupled, sometimes with additional t ...

the eggs are visible through the skin. The eggs take about 65 days to hatch. Their breeding season is roughly July to February.