Strophurus williamsi

Strophurus williamsi
	Eastern spiny-tailed gecko in Pilliga forest, NSW, Australia
Conservation status
	; Least Concern (IUCN 3.1)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Family:	Diplodactylidae
Genus:	Strophurus
Species:	S. williamsi
Binomial name
	Strophurus williamsi; (Kluge, 1963)
Synonyms
	Diplodactylus williamsi; Kluge, 1963;

Last updated August 16, 2023

Strophurus williamsi, also known commonly as the eastern spiny-tailed gecko, the soft-spined gecko,^[1]^[2] and Williams' spiny-tailed gecko,^[3] is a species of lizard in the family Diplodactylidae. The species is endemic to semi-arid regions of eastern Australia including Queensland, New South Wales, Victoria and South Australia.^[1]^[2] It has become a popular species as a pet for its distinctive tail features. S. williamsi has been grouped within a clade of seven other species that are believed to have diverged from their ancestors around 20 million years ago.^[4]S. williamsi can be distinguished from closer relatives by arboreality (living in trees) and diurnal (day-active) activity.

Description

S. williamsi is a small-sized, slender bodied gecko with a snout to vent length of 6 cm and tail length of 5 cm. Their main body colour is grey with darker brown/grey patches and spots. Some individuals may display a diamond or reticulated pattern on the dorsal surface. Ventral surfaces are pale grey or white and are dotted with brown or black spots. During the day, individuals can be found basking on thin branches relying on their camouflage colouration to protect them from predators. Their eyes have an orange to red rim around the iris. The toes are long and expanded with well-developed adhesive pads. Toe tips have large adhesive lamellae that decrease in size towards the palm.^[6]

The species can be distinguished from similar looking Strophurus from the rows of enlarged projections along the back of the tail.^[8] These projections, otherwise known as tubercles, occur in four longitudinal rows along the back of the tail and are orange in colour. Studies conducted by Eric Pianka depict that the tails of eastern spiny-tailed geckos have evolved to obtain antipredator functions and are also commonly used in behavioural displays.^[9] The caudal glands are able to project thin streams of a sticky, noxious and odorous substance through the skin ruptures of the mid-dorsal line of the tail. These defence secretions (composed of protein and glycoprotein) can be aimed at a predator by the curving of the tail. It has been found that this caudal-gland ejection (the ejection of a sticky defensive secretion from the tail) has a direct link with lower rates of tail loss in S. williamsi. This may also be due to the elaboration of tubercles surrounding the caudal glands as many other species of gecko rely solely on autotomy to escape predators.^[4]

Another antipredator function is a defensive posture that usually involves lifting and arching of the body and extending the throat while slowly waving the tail from side to side.^[10] During this display, individuals open their mouths exposing their vibrant mouth colour which is usually dark blue or bright yellow.

Males can be distinguished from females from a single diagonal row of cloacal scales. Males generally have one to five scales which are much larger and more prominent in females which have one to three. Males also possess preanal pores which are absent in females.^[11]

Etymology

The specific name, williamsi, is in honour of American herpetologist Ernest Edward Williams.^[3] Their common name 'Eastern-spiny tailed gecko' directly relates to the distinctive features of 'spikes' protruding from the tail.

Taxonomy

The genus Strophurus is one of only two squamate lineages that obtain specialised causal defence glands. Many species in this genus also have caudal ornamentation or bright coloured patterns on the iris, tail and the mouth.^[4] The genus currently contains 20 species which were separated from Diplodactylus which are mostly terrestrial ground-dwelling species.

Ecology and habitat

There are numerous ecosystems and ecoregions which the eastern spiny-tailed gecko inhabits with different vegetation structure and composition. The preferred habitats of S. williamsi are sclerophyll forest, savanna,^[1] eucalypt woodland and eucalypt forest communities. They have also been found bordering the edge of rainforest communities that are adjacent the previously said vegetation communities. Earlier studies have shown S.williamsi is commonly found beneath the loose bark of Callitrius pine or Ironbarks and in tree hollows and tree trunks.^[12] The species is also associated with shrubs, Spinefex, Casuarina, Callitris and Leptospermum.^[13] During the night-time when the species is most active, they can be found foraging on the ground around grassy bushes. There are numerous populations of S.williamsi inhabiting savanna ecosystems without trees and therefore, the species may also occupy other niches that have not yet been studied.

Geographic range

In Australia, S. williamsi is found in north-eastern New South Wales, Queensland, south-eastern South Australia, and north-western Victoria.^[1]^[2] The map below shows a patchy distribution of the species distributed throughout the east of the continent as far north as Cairs in QLD, as south as Adelaide in SA and as west as Bourke in NSW. The species can be commonly found within Murray-Darling woodlands and mallee ecoregion in Victoria. In central NSW and south-west QLD, the semi-arid biome makes up the greatest area of occupation for the species with multiple shifts into surrounding sclerophyll and monsoon communities.^[10] The preferred temperature range of the species is 25–30 °C.

Reproduction

The breeding season for eastern spiny-tailed geckos is from September to February and reproduction is dioecious. S. williamsi is oviparous which is where young are produced through the expulsion of undeveloped eggs rather than giving birth to live young.^[2] Females lay two clutches of two eggs at a time which are generally laid at the base of trees, under rocks or in abandoned burrows that are no longer occupied by other animals.^[14] Eggs hatch within 45–80 days within a temperature range of 27–30 °C and optimal humidity of 70–80%. Three to five days after the hatchlings emerge from the eggs, the juvenile geckos can begin feeding. Subsequent matings can be observed as soon as one hour after the deposition of the clutch occurs. On average, females can produce five clutches per year.

Diet

Eastern spiny-tailed geckos are insectivorous feeding primarily on arthropods. Their main diet consists of crickets, grasshoppers, moths, spiders and termites.

Threats

Strophurus williamsi has been evaluated and categorised by the IUCN as a species of least concern meaning that they are not a focus for conservation because they are not threatened. The species is however, vulnerable to pressure by grazing and habitat loss, mostly occurring due to land clearing for agriculture. Predators of the eastern spiny-tailed gecko include feral cats, larger lizards such as goannas, birds of prey. They are also commonly preyed upon by the pale-headed snake.

Related Research Articles

Strophurus is a genus of lizards in the family Diplodactylidae. All species of Strophurus are endemic to Australia, and are sometimes given the common names phasmid geckos, spiny-tailed geckos, and striped geckos.

The south-western spiny-tailed gecko, also known commonly as the soft spiny-tailed gecko, is a species of lizard in the family Diplodactylidae. The species is endemic to Australia. Two subspecies are recognized.

Diplodactylus vittatus, commonly known as the eastern stone gecko, stone gecko, and wood gecko, is a species of diplodactylid lizards that occurs in forest, shrubland and arid regions across Australia. It is widespread across the states of Queensland, Victoria and New South Wales, commonly found in dry peripheral bushlands. This gecko can be kept as a pet or seen within zoo enclosures.

The northern spiny-tailed gecko is a species of lizard in the family Diplodactylidae. The species is endemic to Australia.

Lucasium byrnei, also known commonly as the gibber gecko, Byrne's gecko, and the pink-blotched gecko, is a species of small, nocturnal lizard in the family Diplodactylidae. The species is endemic to Australia.

Strophurus intermedius, also known commonly as the eastern spiny-tailed gecko or the southern spiny-tailed gecko, is a species of lizard in the family Diplodactylidae. The species is endemic to semi-arid regions of Australia in New South Wales, Northern Territory, South Australia, Victoria and Western Australia, in mallee shrubland and woodland habitats.

The variable fat-tailed gecko or burrow-plug gecko is a diplodactylid gecko endemic to central and arid inland areas of Australia. Widespread across the continent, the variable fat-tailed is most commonly found in sandy desert habitats dominated by Spinifex grasses. They have also been bred in captivity by zoos and as pets.

The border beaked gecko is a gecko endemic to Australia in the family Gekkonidae. It is known for its distinctive beak-like snout and ability to camouflage itself in its surroundings.

The Goldfields spiny-tailed gecko is a species of lizard in the family Diplodactylidae. The species is endemic to Australia.

Strophurus elderi, also known commonly as the jewelled gecko, is a terrestrial, nocturnal species of gecko, a lizard in the family Diplodactylidae. Previously classified within the genus Diplodactylus, S. elderi is one of 22 geckos belonging to the genus Strophurus. The species is endemic to the arid regions of central and north-western Australia.

Strophurus jeanae, also known commonly as the southern phasmid gecko and Jean's spiny-tailed gecko, is a species of gecko, a lizard in the family Gekkonidae. The species is endemic to Australia.

The short-tailed striped gecko, also known commonly as McMillan's spiny-tailed gecko, is a species of lizard in the family Diplodactylidae. The species is endemic to Australia.

The robust striped gecko, also known commonly as Michaelsen's spiny-tailed gecko, is a species of lizard in the family Diplodactylidae. The species is endemic to Australia.

The Exmouth spiny-tailed gecko, also known commonly as Rankin's spiny-tailed gecko, is a species of lizard in the family Diplodactylidae. The species is endemic to Western Australia.

The western spiny-tailed gecko is a species of lizard in the family Diplodactylidae. The species is endemic to Australia.

Strophurus taenicauda, also known commonly as the golden spiny-tailed gecko or the golden-tailed gecko, is a species of lizard in the family Diplodactylidae. The species is endemic to eastern Australia. Three subspecies are recognized.

The Western Shield spiny-tailed gecko, also known commonly as Wellington's spiny-tailed gecko, is a species of lizard in the family Diplodactylidae. The species is endemic to Australia.

The Mount Augustus spiny-tailed gecko, also known commonly as the Mount Augustus striped gecko and Wilson's spiny-tailed gecko, is a species of lizard in the family Diplodactylidae. The species is endemic to Australia.

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.

References

1 2 3 4 5 Hobson, R.; Venz, M. (2018). "Strophurus williamsi". IUCN Red List of Threatened Species . 2018: e.T102702792A102702815. doi: 10.2305/IUCN.UK.2018-1.RLTS.T102702792A102702815.en . Retrieved 23 October 2022.
1 2 3 4 Strophurus williamsi at the Reptarium.cz Reptile Database. Accessed 23 October 2022.
1 2 Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore: Johns Hopkins University Press. xiii + 296 pp. ISBN 978-1-4214-0135-5. (Strophurus williamsi, p. 286).
1 2 3 Melville, Jane; Schulte, James A.; Larson, Allan (2004). "A molecular study of phylogenetic relationships and evolution of antipredator strategies in Australian Diplodactylus geckos, subgenus Strophurus". Biological Journal of the Linnean Society. 82: 123–138. doi:10.1111/j.1095-8312.2004.00324.x.
↑ Gilding, Lockie (2017). "Eastern Spiny-tailed Gecko (Strophurus williamsi)". Flickr. Retrieved 19 October 2020.
↑ Laube, A (2013). "Reptile Forums UK: Strophurus Williamsi". Reptile Forums UK. Retrieved 20 October 2020.
↑ Kieran, Palmer (2015). "Eastern spiny-tailed gecko from Barcaldine, central QLD". Flickr. Retrieved 19 October 2020.
↑ "Strophurus williamsi". www.jcu.edu.au. 2015-10-19. Retrieved 2020-10-14.
↑ Pianka, ER (1976). "Comparative ecology of twelve species of nocturnal lizards (Gekkonidae) in Western Australia". Copeia. 1976: 125–142. doi:10.2307/1443783. JSTOR 1443783.
1 2 Neilson, SV (2016). "Stripes, jewels and spines: further investigations into the evolution of defensive strategies in a chemically defended gecko radiation (Strophurus, Diplodactylidae)". Zoologica Scripta. 45 (5): 481–493. doi:10.1111/zsc.12181. hdl: 10072/411159 . S2CID 89325880.
↑ Kluge, AG (1963). "A new species of gekkonid lizard, genus Diplodactylus Gray, from Eastern Australia". Proceedings of the Linnean Society of New South Wales. 22: 230–234.
↑ James Cook University (n.d.). "Strophurus williamsi". James Cook University. Retrieved 20 October 2020.
↑ "Eastern Spiny-tailed Gecko | Central QLD Coast Landcare Network". cqclandcarenetwork.org.au. Retrieved 2020-10-20.
↑ Suárez, Miguel A. (2019-02-10). "Strophurus: australian spiny-tailed geckos". HerpetoNatura. Retrieved 2020-10-20.