Chevron skink  (Oligosoma homalonotum)

Classified as Vulnerable (VU) on the IUCN Red List 2007 (1).

The chevron skink is New Zealand’s largest living endemic lizard and one of its rarest (2) (4), and is named after its very distinctive markings. The mouth is striped with black and white bands, creating a white tear drop mark under each eye, and alternating pale- and dark-brown v-shaped markings run along the smooth back and tail. The underside is pale with scattered spots (3) (5). Fairly unusually for a lizard, the chevron skink will grunt or squeak if disturbed (4).

Occurs only on Great Barrier Island and Little Barrier Island, off the coast of New Zealand. However, the status of the species on Little Barrier Island is uncertain, as only one individual has ever been found (2).

The chevron skink is restricted to damp areas and is found most often along water courses, among wet leaf litter and in damp, rotten logs (2) (5).

Less than 250 sightings of the chevron skink have been reported since it was first described in 1906, and thus very little is known about the biology or ecology of this rare lizard (4). It is known to be diurnal and insectivorous (2), but little is known about the specific animals that it feeds upon (5). A female may produce up to eight offspring in late summer or early autumn, with young taking up to four years to attain sexual maturity (2).

The chevron skink’s main threat is from alien species, accidentally or intentionally introduced to the islands. On Great Barrier Island, the chevron skink is preyed on by cats and pigs, and while cats were removed from Little Barrier Island in 1980, rodents may also prey on skinks on both islands (2). Habitat degradation by browsing feral cattle and goats poses an additional threat (2). The unintentional release or deliberate introduction of further predators could have a potentially devastating impact, particularly the Norway rat (Rattus norvegicus), which inhabits the edges of water courses and wet places also favoured by the chevron skink (2) (4).

A Chevron Skink Recovery Plan was composed and initiated by the New Zealand Department of Conservation in 1993, which outlined numerous actions for the species’ recovery (2). As a result, an intensive research project was undertaken on Great Barrier Island between 1997 and 2002, looking at the chevron skink’s habitat requirements. New and improved techniques for detecting the well camouflaged skink are now being developed (4). A captive population at Auckland Zoo is also providing information on the species behaviour and biology, which can be used to inform further conservation actions (2).

View information on this species at the UNEP World Conservation Monitoring Centre.

For further information on the chevron skink see:

• New Zealand Department of Conservation:
  www.conservation.govt.nz/templates/podcover.aspx?id=33136