Oligosoma microlepis

Small-scaled skink

Oligosoma microlepis
(Patterson & Daugherty, 1990)

Small-scaled skink (Rangitīkei District). © Nick Harker
Image attribution
Small-scaled skink (Rangitīkei District). © Nick Harker
Herpetofaunal category
NZ Skinks
Species complex
Conservation Status
Threatened - Nationally Vulnerable
Common names
Small-scaled skink

Length: SVL up to 73mm, with the tail often being longer than the body length

Weight: up to 13 grams

Description

Small-scaled skinks are a small and distinctive looking species from the central North Island. A close relative of the shore skink (Oligosoma smithi), they are descended from common ancestors which became trapped inland as the coastline expanded outwards during the Pliocene.

Head is short and blunt with distinctive teardrop markings under their strikingly dark eyes. Dorsal surfaces are light grey-brown in colour with a dark mid-dorsal stripe, lighter coloured flecks, and pale dorso-lateral stripes which are crenulated at the margins giving the dorsum a checker-board appearance. Flanks have a broad dark brown-grey lateral stripe bordered below by a lighter coloured lower-lateral stripe which is also crenulated at the margins. Lower (ventral) surfaces are pale cream or white without speckles. In tact tail is longer than the body length (SVL).

Life expectancy

Unknown.

Distribution

Occurs only in the central North Island. Found around Lake Taupo (including Motutaiko Island in the lake), the Rangitikei River, Ruahine Ranges, and just north of Taihape.

Ecology and habitat

Small scaled skinks are diurnal and avid sun-baskers which can often be seen basking fully exposed in their habitat. They are terrestrial and mainly inhabit rocky substrates exposed to the sun including screes, rock outcrops, cliffs, pebble and boulder banks on the edges of rivers and sometimes dense vegetation associated with such habitats. Small-scaled skinks will now often occur in modified or marginal habitat on agricultural land.

Social structure

Thought to be largely solitary, but can live in dense colonies.

Breeding biology

The reproductive biology of small-scaled skinks is poorly known, but females in captivity are known to give birth to litters of 2-3 young in January-March.

Diet

Diet includes small invertebrates. Small-scaled skinks have been observed hunting and consuming small insects such as flies in the wild. They likely also consume the berries / fruit of native plants, in common with other species of New Zealand skinks.

Disease

Unknown.

Conservation strategy

Small scaled skinks are secure on one pest-free island (Motutaiko Island), elsewhere they are exposed to the full suite of introduced predators on the mainland.

A population is held in captivity for insurance purposes.

Interesting notes

Small scaled skinks are descended from common ancestors with shore skinks (Oligosoma smithi) which became trapped inland as the coast expanded outwards during the Pliocene.

References

Chapple, D. G., Ritchie, P. A., & Daugherty, C. H. (2009). Origin, diversification, and systematics of the New Zealand skink fauna (Reptilia: Scincidae). Molecular phylogenetics and evolution52(2), 470-487.

Daugherty, C. H., Patterson, G. B., Thorn, C. J., & French, D. C. (1990). Differentiation of the members of the New Zealand Leiolopisma nigriplantare species complex (Lacertilia: Scincidae). Herpetological monographs, 61-76.

Hitchmough, R., Barr, B., Knox, C., Lettink, M., Monks, J. M., Patterson, G. B., Reardon, J. T., van Winkel, D., Rolfe, J., & Michel, P. (2021). Conservation status of New Zealand reptiles, 2021New Zealand threat classification series 35. Wellington: New Zealand Department of Conversation.

Hitchmough, R.A., Barr, B., Lettink, M., Monks, J., Reardon, J., Tocher, M., van Winkel, D., Rolfe, J. (2016). Conservation status of New Zealand reptiles, 2015; New Zealand threat classification series 17. Wellington: New Zealand Department of Conservation.

Jewell, T. (2011). A photographic guide to reptiles and amphibians of New Zealand. Auckland: New Holland Publishing.

Nelson-Tunley, M. (2012). Population fragmentation in the small-scaled skink (Oligosoma microlepis): the consequences of human landscape transformation on a habitat specialist's distribution, morphology, and genetics: a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Manawatu, New Zealand (Doctoral dissertation, Massey University).

Nelson-Tunley, M., Morgan-Richards, M., & Trewick, S. A. (2016). Genetic diversity and gene flow in a rare New Zealand skink despite fragmented habitat in a volcanic landscape. Biological Journal of the Linnean Society119(1), 37-51.

Patterson, G. B., & Daugherty, C. H. (1990). Four new species and one new subspecies of skinks, genus Leiolopisma (Reptilia: Lacertilia: Scincidae) from New Zealand. Journal of the Royal Society of New Zealand20(1), 65-84.

Patterson, G. B., & Daugherty, C. H. (1995). Reinstatement of the genus Oligosoma (Reptilia: Lacertilia: Scincidae). Journal of the Royal Society of New Zealand25(3), 327-331.

Robb, J. (1986). New Zealand Amphibians & Reptiles (Revised). Auckland: Collins, 128 pp.

Towns, D. R., Neilson, K. A., & Whitaker, A.H. (2002). North Island Oligosoma spp. skink recovery plan 2002–2012: Threatened species recovery plan 48. Wellington: Department of Conservation.

van Winkel, D., Baling, M. & Hitchmough, R. (2018). Reptiles and Amphibians of New Zealand: A field guide. Auckland: Auckland University Press, 376 pp.