Saturday 3 March 2012

A new Bent-toed Gecko from Western Australia.

Bent-toed Geckos are widespread across South-East Asia, the Malay Archipelago and as far south as Victoria State, Australia. They are smallish Geckos noted for an outward bend in the middle digit of their hindlimbs, typically living in rainforest environments.

In a paper published in the journal Zootaxa on 9 February 2012, Aaron Bauer of the Department of Biology at Villanova University and Paul Doughty of the Department of Terrestrial Zoology at the Western Australian Museum describe a new Bent-toed Gecko from East Montalivet Island off the north coast of the Kimberley region of Western Australia.

The new species has been named as Cyrtodactylus kimberleyensis, the Kimberly Bent-toed Gecko. It is described from a single female presumed to be an adult because it was gravid (pregnant with an egg). This individual was about 45 mm long, making the new species the second smallest member of the genus if this individual is typical, surpassed only by C. laevigatus, a species from Komodo and Flores with an average length of adult 43 mm. It is brownish, elongate and slender.

Cyrtodactylus kimberleyensis in life. Bauer & Doughty (2012).

Cyrtodactylus kimberleyensis was discovered on a small island off the Kimberly Coast of Western Australia. It is the first species of Cyrtodactylus discovered in Western Australia, though there are five species known in Queensland. Interestingly Cyrtodactylus kimberleyensis appears to be more closely related to the Bent-toed Geckos of Timor and the Banda Arc than it is to those of Victoria and New Guinea, suggesting a separate Australian colonization event. Bauer & Doughty note that most species discovered in the forests of the coast and islands of Kimberly are related to species in the interior dry-grasslands of the region, and speculate about finding Cyrtodactylus kimberleyensis or related species on the mainland. They note that despite being a biodiversity hotspot the fauna of the area is not well studied, so other links with Timor and the Banda Arc may emerge with further study.

The Kimberly Coast of Western Australia, showing East Montalivet Island where Cyrtodactylus kimberleyensis was found. Bauer & Doughty (2012).

The individual discovered was gravid with a single egg. If this is typical then this is another way in which Cyrtodactylus kimberleyensis is distinctive, since small Geckos, like most small Lizards typically produce clutches of two eggs.

The hind foot of Cyrtodactylus kimberleyensis, showing why it is called a 'Bent-toed' Gecko. Scale bar is 2 mm. Bauer & Doughty (2012).