Monday 12 March 2012

New species of Skink from northwest New Caledonia.

Skinks are smallish lizards with elongate bodies and reduced legs and necks. They are an ancient and successful group, found throughout the tropical, subtropical and warm temperate regions of the world, though individual species (of which there are over 12 000) may be threatened. Skinks can either lay eggs or bear live young (depending on species) and can be divided into tree-dwelling and ground-dwelling species, though this is an ecological rather than a taxonomic distinction; ground-dwelling species tend to have much more reduced limbs than tree-dwelling species, often being quite snake-like. Most skinks are insectivorous, but some will eat vegetable matter, or small rodents.

On 9 March 2012, in a paper in the journal Zootaxa, a team of biologists led by Ross Sadlier of the Section of Herpetology at the Australian Museum, describe the discovery of a new species of skink from the woodlands of northwest New Caladonia.

The species is described as Caledoniscincus constellatus, the Star-studded Caledonian Skink. It is a brown skink with a yellow underside and a white lateral stripe (stripe along its side), the adults of which are 46-57 mm in length. It is a tree-dwelling species found in Acacia Scrub and Mediterranean Woodland. Reproductive and feeding behavior were not recorded.

Male Star-studded Caledonian Skink, Caledoniscincus constellatus. From Sadlier et al. (2012).

There are two other species of Caladonian Skink with white lateral stripes, both of which share at least part of their range with C. constellatus. C. haplorhinus and C. austrocaledonicus. In C. constellatus the lateral stripe is broad and solid when it reaches the ear opening, but in C. haplorhinus, it is narrow and starting to break up. C. austrocaledonicus does not always have a lateral stripe, and where it does this does not reach the ear. Genetic studies have confirmed these are three separate species.

The heads of (A) C. constellatus, (B) C. haplorhinus, and (C) C. austrocaledonicus, showing the position of the lateral stripe at the head. From Sadlier et al. (2012).

C. constellatus is known only from two sites in the northwest of New Caledonia. These are threatened by deforestation by expanding agriculture and ranching, which fragments the landscape and makes it vulnerable to forrest fires, habitat loss due to nickel mining at the Koniambo Mine, and the harmful effects of the invasive Little Red Fire Ant (Wasmannia auropunctata). If these turn out to be the only places where it lives, then C. constellatus would meet the criteria for inclusion in the Critically Endangered category on the IUCN Red List.

Map of northern New Caledonia, showing the two locations where C. constellatus was found. From Sadlier et al. (2012).

The localities where C. constellatuswas found. (A) Acacia scrubland at Pointe de Vavouto. (B) Mediterranean Forrest on Massif Ouazangou. From Sadlier et al. (2012).