Burton's legless lizard

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Burton's legless lizard
Lialis burtonis wild shot.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Pygopodidae
Genus: Lialis
Species:
L. burtonis
Binomial name
Lialis burtonis
Gray, 1835
Lialis burtonis distribution.svg

Burton's legless lizard (Lialis burtonis) is a species of lizard in the family Pygopodidae. The species lacks forelegs and has only rudimentary hind legs. [2] Pygopodid lizards are also referred to as "legless lizards", [3] "flap-footed lizards" [4] and "snake-lizards". [5] This species is native to Australia and Papua New Guinea. [6]

Contents

Taxonomy

English zoologist John Edward Gray described Burton's legless lizard in 1835. [7] The specific name, burtonis, is in honour of British army surgeon Edward Burton (1790–1867). [8] Burton's legless lizard (Lialis burtonis) is a member of the genus Lialis within the family Pygopodidae. [4] There are approximately 40 species in the family Pygopodidae, however, Burton's legless lizard and another species (L. jicari) are the only species that fall within genus Lialis. [4] Members in genus Lialis are considered analogous to macrostomatan snakes as these taxonomic groups have functionally similar adaptations such as the ability to swallow relatively large prey whole. However, their resemblance to snakes is merely superficial example of convergent evolution, and they are not closely related. [4] [9]

Differences between legless lizards and snakes include the lack of venom glands in legless lizards, their inability to constrict prey, the presence of a fleshy tongue rather than a forked tongue, visible ear holes, and remnant hind limbs. [4] [9] [10] Burton's legless lizard and the Pygopodidae, as a whole, are members of the infraorder Gekkota, meaning that they are essentially legless geckos. [11] [12] [13] Pygopods are the namesake of the Australasian gecko superfamily Pygopodoidea (sometimes called Diplodactyloidea), and they are the sister taxon to legged geckos in the family Carphodactylidae. [14] [15]

Description

Burton's legless lizard and its elongated snout and distinctive wedge-shaped head Lialis burtonis.jpg
Burton's legless lizard and its elongated snout and distinctive wedge-shaped head

Burton's legless lizard has significant morphological adaptations to enable it to deal with large struggling prey items. [9] The first adaptation is a skull with an elongated snout that may, along with its pointed, recurved and hinged teeth, be an adaptation that assists it to grip its prey. [16] In addition, this elongated snout may also promote binocular vision which would allow strikes to be more accurately directed. [9] Another adaptation that assists Burton's legless lizard to hold its prey is its flexible mesokinetic and hypokinetic joints which allow its jaws to encircle prey. [9] [16] Lastly, the ability of the species to retract its eyes is of key importance as it is a visual predator that relies on eyesight and this adaptation effectively protects them during conflict. [9]

Distribution and habitat

Burton's legless lizard occurs almost Australia wide but it is absent in parts of southern Australia including Tasmania. [6] This species is also found in Papua New Guinea, although populations are limited to one small area. [6]

Burton's legless lizard is found in a variety of habitats from deserts to the margins of rainforests but not in southern alpine areas and extreme northern deserts as would be expected based on its distribution. [6] [10] It is usually found in low vegetation or debris on the ground such as leaf litter which has been shown to be important to specimens located in tropical environments. [4] [6] This was demonstrated in an experiment where individuals were given a choice of several thermally comparable environments and there was an overwhelming preference for leaf litter by specimens from the tropics. [4] In areas where leaf litter is not as readily available this species will use grasses, abandoned burrows and other shelter that it can find as habitat. [10]

Burton's legless lizard on some sticks Burton's legless lizard habitat shot.jpg
Burton's legless lizard on some sticks

Diet

L. burtonis feeds almost exclusively on lizards. [6] [10] [17] Generally, skinks are the main prey item taken but other legless lizards and geckos are also a part of the diet of Burton's legless lizard. [3] [10] [17] In addition, it has been reported that this species will eat small snakes on rare occasions and this has been documented in a study of the stomach contents of museum specimens. [18] Notably, this species also feeds rather infrequently according to a recent study. [4]

Reproduction

Burton's legless lizard on sand Lialis b. habitat shot.JPG
Burton's legless lizard on sand

Reproduction seems to be seasonal in populations of Burton's legless lizard and mating occurs at similar times throughout Australia. [4] [10] Ovulation and mating for the species usually occurs from September until summer. [4] [10] The species is oviparous and eggs are generally laid from November to January, although, reproduction can occur at any time outside of the usual breeding season and females are capable of laying more than one clutch each year. [4] [18] Eggs are laid under logs or rocks, on the ground, under leaf litter and sometimes in the nests of sugar ants. [10]

Clutches can be laid in quick succession with each clutch containing 1 to 3 tough, leathery eggs, although a clutch size of 2 eggs is by far the most common. [18] [19] Nesting can be communal and up to 20 eggs have been found in a nest. [10] [18] Another characteristic that has been discovered is the ability of females of this species to either store sperm for reproduction at a later time or to reproduce through parthenogenesis which does not require mating to be successful. [4] Hatchlings are approximately 13 centimetres long. [10]

Captivity

In Australia a license is required to keep the Burton's legless lizard as a pet.[ citation needed ]

Behaviour

Burton's legless lizard cleaning its spectacle Burton's legless lizard headshot.jpg
Burton's legless lizard cleaning its spectacle

Burton's legless lizard is generally a diurnal feeder as prey is most commonly encountered during the day but it can be active at any time. [4] This is highlighted as its movements tend to be nocturnal to take advantage of benefits such as reduced risks of hyperthermia during hot conditions and reduced risks of predation from diurnal predators like raptors. [4] Another reason for it to move at night is to avoid revealing its ambush position in the day when it has the highest likelihood of encountering an otherwise unsuspecting prey item. [4] In addition, there is geographic variation in movement and feeding patterns which is expected as this species is very widespread and inhabits a variety of different environments. [4]

This lizard is a visually oriented predator that strikes based on movement and requires shelter to ambush its prey. [4] Shelter is also required to hide from predators and may be particularly important after feeding as individuals become more sedentary than usual which is thought to be an anti-predator response. [20] Alternatively, shelter also plays a key role in lizard thermoregulation. [4] Deep leaf litter for example, is very good shelter as individuals can bury themselves at an appropriate depth to regulate temperature and remain hidden at the same time. [4]

Burton's legless lizard also uses caudal luring as a feeding strategy which is rare in lizards. [21] Notably, this behaviour only occurs if its initial ambush attack is unsuccessful in capturing its intended prey. [21] However, this tactic is not exhibited every time that prey escapes as the likelihood of this tactic being used increases with time since an individual's last meal. [21] Caudal luring can be used to recapture prey in 3 ways as it can be used to lure prey towards it, to distract prey at the moment that it strikes or both. [21]

Feeding strategies are a very important behaviour for this species as the lizards it eats can often be large enough to inflict a retaliatory bite that could cause serious harm. [9] This is thought to be the reason that this species will modify its strike precision according to prey size as strikes at large prey will be directed at either the head or neck to prevent them from biting back. [9] Furthermore, Burton's legless lizard will hold large prey until it is incapacitated before swallowing to prevent harm to itself whereas it swallows small prey that is still struggling as swallowing live prey costs less energy than waiting for it to be incapacitated. [9]

This species also has a tendency to vocalise, especially, when it is threatened. [5] Furthermore, if it is seized by a predator it can drop its tail like many other lizards. [4] However, there are substantial costs associated with a lizard losing its tail as it requires time and energy to grow back. [4]

Burton's legless lizard on a rocky surface Burton's conservation.JPG
Burton's legless lizard on a rocky surface

Conservation

L. burtonis is not a priority for conservation as it is Australia's most widespread reptile and inhabits almost all Australian habitat types with only a few exceptions. [4] [6] In addition, it is not known how abundant Burton's legless lizard is, but there has been no indication that this species is rare or rapidly declining. [4] [6]

Related Research Articles

<span class="mw-page-title-main">Lizard</span> Informal group of reptiles

Lizard is the common name used for all squamate reptiles other than snakes, encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The grouping is paraphyletic as some lizards are more closely related to snakes than they are to other lizards. Lizards range in size from chameleons and geckos a few centimeters long to the 3-meter-long Komodo dragon.

<span class="mw-page-title-main">Pygopodidae</span> Family of lizards

Pygopodidae, commonly known as snake-lizards, or flap-footed lizards, are a family of legless lizards with reduced or absent limbs, and are a type of gecko. The 47 species are placed in two subfamilies and eight genera. They have unusually long, slender bodies, giving them a strong resemblance to snakes. Like snakes and most geckos, they have no eyelids, but unlike snakes, they have external ear holes and flat, unforked tongues. They are native to Australia and New Guinea.

<i>Underwoodisaurus</i> Genus of lizards

Underwoodisaurus is a small genus of Australian lizards in the family Carphodactylidae. Member species are commonly known as thick-tailed geckos, along with the species Uvidicolus sphyrurus.

<i>Lialis</i> Genus of lizards

Lialis is a genus of legless lizards in the family Pygopodidae. The genus is native to Australia and New Guinea.

<span class="mw-page-title-main">Legless lizard</span> Common name for a lizard without obvious legs

Legless lizard may refer to any of several groups of lizards that have independently lost limbs or reduced them to the point of being of no use in locomotion. It is the common name for the family Pygopodidae. These lizards are often distinguishable from snakes on the basis of one or more of the following characteristics: possessing eyelids, possessing external ear openings, lack of broad belly scales, notched rather than forked tongue, having two more-or-less-equal lungs, and/or having a very long tail. Every stage of reduction of the shoulder girdle —including complete loss— occurs among limbless squamates, but the pelvic girdle is never completely lost regardless of the degree of limb reduction or loss. At least the ilium is retained in limbless lizards and most basal snakes.

<span class="mw-page-title-main">Brigalow scaly-foot</span> Species of lizard

The Brigalow scaly-foot, also known as the Queensland snake-lizard, is a species of legless lizard in the family Pygopodidae. It is endemic to Australia and is the only species in the monotypic genus Paradelma.

<i>Anniella pulchra</i> Species of lizard

Anniella pulchra, the California legless lizard, is a limbless, burrowing lizard often mistaken for a snake.

<span class="mw-page-title-main">Common scaly-foot</span> Species of lizard

The common scaly-foot is a widespread species of legless lizard in the Pygopodidae family. It is endemic to Australia.

<span class="mw-page-title-main">Carphodactylidae</span> Family of lizards

The Carphodactylidae, informally known as the southern padless geckos, are a family of geckos, lizards in the infraorder Gekkota. The family consists of 34 described species in 7 genera, all of which are endemic to Australia. They belong to the superfamily Pygopodoidea, an ancient group of east Gondwanan geckos now only found in Australasia. Despite their well-developed limbs, molecular phylogenies have demonstrated that Carphodactylidae is the sister group to Pygopodidae, a highly specialized family of legless lizards.

<span class="mw-page-title-main">Diplodactylidae</span> Family of lizards

The Diplodactylidae are a family in the suborder Gekkota (geckos), with over 150 species in 25 genera. These geckos occur in Australia, New Zealand, and New Caledonia. Diplodactylids are the most ecologically diverse and widespread family of geckos in both Australia and New Caledonia, and are the only family of geckos found in New Zealand. Three diplodactylid genera have recently been split into multiple new genera.

<span class="mw-page-title-main">Hooded scaly-foot</span> Species of lizard

The hooded scaly-foot, also known as western scaly-foot, black-headed scaly-foot or western hooded scaly-foot, is an endemic Australian legless lizard of the family Pygopodidae.

Nephrurus sheai, also known commonly as the Kimberley rough knob-tailed gecko and the northern knob-tailed gecko, is a species of lizard in the family Carphodactylidae. The species is endemic to Australia.

The eastern hooded scaly-foot or eastern scaly-foot is a species of flap-footed lizard found in the complex heaths of the lower west coast and the spinifex grasslands of mainland Australia. They are popular pets and are often mistaken for snakes due to their limbless appearance.

<span class="mw-page-title-main">Papua snake lizard</span> Species of lizard

The Papua snake lizard, also known commonly as Jicar's snake-lizard, the New Guinea snake-lizard, and the Papua snake-lizard, is a species of legless lizard in the family Pygopodidae. The species is endemic to New Guinea including the Bismarck Archipelago.

<span class="mw-page-title-main">Pygopodoidea</span> Superfamily of lizards

Pygopodoidea is a gecko superfamily and the only taxon in the gekkotan subclade Pygopodomorpha. The clade includes three Australasian families: Diplodactylidae, Carphodactylidae, and Pygopodidae. Traditional gekkotan systematics had considered Diplodactylidae and Carphodactylidae as subfamilies of the family Gekkonidae, but recent molecular work have placed Pygopodidae within Gekkonidae making it paraphyletic. These analyses have shown support of Pygopodidae and Carphodactylidae being sister taxa, with Diplodactylidae occupying a basal position in Pygopodoidea.

<span class="mw-page-title-main">Excitable delma</span> Species of lizard

The excitable delma is a species of lizard in the Pygopodidae family endemic to Australia. The lizard gets its name from its active and jumpy defense mechanism. It will erratically jump multiple times in succession, each jump pivoting its body in a different direction. D. tincta is a slender, long legless lizard that through evolution lost its limbs. It is found throughout Australia in a variety of habitats, and spends most of its time hiding. Due to its nocturnal nature, it is rare to spot in the wild. This legless lizard is small to moderate in size, with a tail that is three to four times its body length. The typical size of the excitable delma is 250 – 300 mm. This lizard is an insectivore and feeds on insects it finds when travelling through grass, logs, surface soil, and loose rocks. Like all pygopodids, the excitable delma is oviparous and only lays two eggs per clutch.

<i>Aprasia inaurita</i> Species of lizard

The Mallee worm-lizard , also known as the pink-nosed worm-lizard and the red-tailed worm-lizard, is a slender pygopid species that is endemic to Australia, with recorded distribution across the four southern mainland states, although its distribution is restricted in Western Australia and New South Wales.

<span class="mw-page-title-main">Zuytdorp worm-lizard</span> Species of lizard

The Zuytdorp worm-lizard, also known commonly as Smith's legless lizard, is a species of lizard in the family Pygopodidae. The species is endemic to Australia.

The striated worm-lizard is a species of legless lizard in the family Pygopodidae. It is endemic to southern Australia. Commonly known as Striated worm-lizard but has also been referred to as the Striped or Lined worm-lizard due to its pattern of long, thin parallel streaks. Some populations such as those in WA and Kangaroo Island may have absent stripes or the lines present as lines of dots.

<span class="mw-page-title-main">Olive legless lizard</span> Australian lizard species

The olive legless lizard is a species of legless gecko from the Pygopodidae family. This species is commonly found throughout the Australian Capital Territory, New South Wales, Queensland, Victoria and southeastern South Australia, mostly inhabiting areas consisting of dry to temperate southern grasslands and grassy woodlands.

References

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Further reading

Commons-logo.svg Media related to Lialis burtonis at Wikimedia Commons