The hooded scaly-foot (Pygopus nigriceps), 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.[2][3]
| Hooded scaly-foot | |
|---|---|
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Order: | Squamata |
| Family: | Pygopodidae |
| Genus: | Pygopus |
| Species: | P. nigriceps
|
| Binomial name | |
| Pygopus nigriceps (Fischer, 1882)
| |
| |
| Synonyms | |
|
Cryptodelma nigriceps Fischer, 1882 | |
Description
editAdult hooded scaly-foots range from 45 to 55 cm long,[4][5] with an average snout to vent length of 22.7 cm.[6] Females are generally larger than males.[3] Hooded scaly-foots show no trace of forelimbs, whilst the hind limbs are reduced to scaly flaps.[3][4][7] These hind limbs are small and paddle-shaped, with modified scales which do not aid in movement.[4][5]
The scales of the hooded scaly-foot are smooth and weakly glossed.[4][5][8] Usually, it has 120 or more ventral scales,[6][8] which are in a paired series, much larger than the adjacent body scales.[6][7] Body colour varies from brown to reddish-brown,[6] with desert specimens usually a more orangish colour and other individuals a duller brown.[4] It is white below.[5][7] The species has little to no body pattern, with oblique dark lines converging mid-dorsally.[6][8]
These scaly-foots are characterised by black bands across the head and neck which may look like a hood.[6][7][8] This hood comprises a band across the eyes onto the lips, a dark smudge on the nostrils, and a broad band across the neck.[5][6][8] These dark bands may fade or merge with age.[5][7] The lidless eye is well developed,[4][7] covered with a transparent spectacle.[3][8] The species is able to lick clean this spectacle using its broad, fleshy tongue.[5] It also retains conspicuous ear openings.[3][5]
The hooded scaly-foot can be differentiated from the four other species in the genus Pygopus if the nostril contacts the first upper labial scale.[6][8]
Ecology
editThe hooded scaly-foot is found throughout Australia, except for the wetter areas of the south and Tasmania.[4][7]
The species is mostly nocturnal, due to the generally hot weather where it occurs, although in cooler conditions, it forages by day.[4][5] It is a terrestrial surface-dweller, but individuals have been noted up to 1.5 m above the ground in vegetation.[7] Captive scaly-foots have lived up to seven years, but little is known about ages of individuals in the wild.[7]
Hooded scaly-foots are found in a range of habitats,[4][5] favouring dry open habits.[6] They are found particularly in sandy deserts vegetated with triodia,[6][7] but also in open woodlands and shrublands.[5] The species shelters under rocks and woody debris, in grass tussocks and soil cracks, abandoned burrows, insect holes, and in termite mounds.[5][6][8]
Diet
editThe hooded scaly-foot feeds predominantly on surface-active arthropods.[3][6][8] Insects are the main prey type, while it is also noted to feed on spider egg sacks and scorpions.[3][5][6][7] The species has been observed to actively search for prey.[7] Once caught, larger prey is crushed and disabled as the hooded scaly-foot rotates its body rapidly, in a crocodile-roll fashion.[5][7] Body fluids are then licked up.[5]
Behavior and defense
editScaly-foots move through lateral undulations of their bodies and tails,[7] and in open terrain they have been noted to move in wriggling leaps.[8] The hind-limb flaps are held alongside the body during movement, although they may be extended when stressed or when climbing.[7] As stated earlier, hooded scaly-foots have a voice. This harsh squeak is emitted under stress and occasionally in social interactions.[7]
When disturbed, hooded scaly-foot raise their heads and fore parts of their bodies from the ground, flatten their necks, and flicker their tongues, occasionally striking out.[5][6][7] The species does this in apparent mimicry of venomous snakes, to deter predators.[5][6][7] The markings on the hooded scaly-foot resemble those of young brown snakes.[6] When grasped, they struggle fiercely, rotating their bodies and uttering long squeaking sounds.[6] They readily shed their tails and will regenerate a new one.[4][8] The regenerating tail can be identified through a change in scale arrangement and pattern.[8]
Reproduction
editHooded scaly-foots are oviparous, laying two parchment-shelled eggs per clutch.[5][7] Pygopus species have been noted to lay communally,[3][7] while known incubation periods range from 66 to 77 days.[7] Pelvic spurs, modified spine-like scales, are found in addition to the hind-limb ‘flaps’ on males, are thought to assist the male in gripping the female.[4]
Predation
editPredators of the hooded scaly-foot include: raptors, elapid snakes, goannas, feral cats, and foxes. Burton's snake lizard (Lialis burtonis) is also known to eat legless lizards. In all cases, legless lizards are a minor component of the predator's diet.[7]
References
edit- ^ Cowan, M., How, R. & Ellis, R. 2017. Pygopus nigriceps. The IUCN Red List of Threatened Species 2017: e.T102831509A102831677. https://doi.org/10.2305/IUCN.UK.2017-3.RLTS.T102831509A102831677.en. Downloaded on 11 February 2019.
- ^ Pygopus nigriceps at the Reptarium.cz Reptile Database. Accessed 9 September 2020.
- ^ a b c d e f g h Patchell, Frederick; Richard Shine (February 1986). "Food habits and reproductive biology of the Australian legless lizards (Pygopodidae)". Copeia. 1986 (1): 30–39. doi:10.2307/1444884. JSTOR 1444884.
- ^ a b c d e f g h i j k Hoser, Raymond (1989). Australian Reptiles and Frogs. Pierson & Co. pp. 79–83.
- ^ a b c d e f g h i j k l m n o p q r Cronin, Leonard (2001). Australian Reptiles and Amphibians. Envirobook. p. 166.
- ^ a b c d e f g h i j k l m n o p q Wilson, Steve (2003). A Complete Guide to Reptiles of Australia. New Holland: Reed. pp. 102–122.
- ^ a b c d e f g h i j k l m n o p q r s t u v Shea, Glenn. "Fauna of Australia: Family Pygopodidae" (PDF). Archived from the original (PDF) on 24 August 2012. Retrieved 16 June 2012.
- ^ a b c d e f g h i j k l Wilson, Steve (2005). A Field Guide to Reptiles of Queensland. Australia: New Holland. pp. 62–69.