Oligosoma aff. waimatense "Marlborough"

Marlborough scree skink

Oligosoma aff. waimatense "Marlborough"

Marlborough scree skink. <a href="https://www.instagram.com/nickharker.nz/">© Nick Harker</a>
Image attribution
Marlborough scree skink (Wairau, Marlborough). © Nick Harker
Herpetofaunal category
NZ Skinks
Species complex
Conservation Status
Threatened - Nationally endangered
Other Names
Marlborough scree skink
Scree skink
Previous scientific names
Oligosoma waimatense.
Common names
Marlborough scree skink

Length: SVL up to 114 mm, with the tail being much longer than the body length.

Weight: Up to at least 28 grams.

 

Description

A beautiful, undescribed species of skink that was recently recognized as a distinct taxon with a snout-vent-length (SVL) up to 114 mm. Dorsal surface typically bright golden or tan (sometimes with olive-green tint) with pronounced black transverse bands and black edging to many of the scales around the mid-dorsal area. There is sometimes a conspicuous "gap" along the dorsolateral area, where bold black bands are absent. The lateral surfaces are similar to the dorsal surface, with bold black transverse bands extending most of the way to the ventral surface. However, the basal color of the mid-lower portion of the lateral surfaces quickly transition to a pale grey color. Ventral surface and throat mostly uniform grey sometimes with a pale pink hue to the belly.

Life expectancy

Upper limit unknown. However, the oldest animals in captivity are known to be around 40 years old.

Distribution

Upper Wairau River, Chalk Range, Clarence River, Inland Kaikōura Range, and Seaward Kaikōura Range.

Ecology and habitat

Marlborough scree skinks are diurnal, saxicolous, and avidly heliothermic. They are highly active and mobile. Marlborough scree skinks occupy lowland, montane/subalpine, and alpine areas. They typically inhabit dry rocky areas with suitable refugia (their large size renders them more vulnerable to predators). These include boulderfields, screes, talus, stoney river terraces, rocky shrubland, and rocky bluffs. Marlborough scree skinks are frequently seen occupying rock tors and bluffs. In these habitats they seek refuge in deep crevices.

Social structure

Unknown.

Breeding biology

Largely unknown, however, scree skinks may breed annually or biennially. Reproductive maturity is thought to be a minimum of 4-5 years of age (Lettink and Monks, 2019).

Diet

Invertebrates, smaller lizards (possibly including conspecifics), and native fruits.

Disease

Marlborough scree skinks are a known host for the ectoparasitic mite Ophionyssus scincorum.

Conservation strategy

Marlborough sree skinks are highly vulnerable to mammalian predation, partly because of their large size. Consequently, they only exist in a few areas in lowland habitat (compared to what their former extent would likely have been), and are more common and widespread at higher altitudes. However, when considering the decline of other mainland lizard populations, including other scree skink populations, it is probable this species is declining as a whole (Lettink and Monks, 2019).

Interesting notes

Marlborough scree skinks have recently been identified as markedly divergent from scree skinks (Oligosoma waimatense). This combined with their geographical separation and morphological differences have led to them being considered a distinct taxonomic unit (Hitchmough et al., 2021).

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.

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.

Lettink, M., & Monks, J. M. (2019). Ecology of scree skinks (Oligosoma waimatense) in O Tu Wharekai Wetland, mid-Canterbury high country, New Zealand. New Zealand Journal of Ecology, 43(1).

Mockett, S. (2017). A review of the parasitic mites of New Zealand skinks and geckos with new host records. New Zealand journal of zoology44(1), 39-48.

O’Donnell, C. F., Weston, K. A., & Monks, J. M. (2017). Impacts of introduced mammalian predators on New Zealand’s alpine fauna. New Zealand Journal of Ecology41(1), 1-22.

Patterson, G. B. (1997). South Island skinks of the genus Oligosoma: description of O. longipes n. sp. with redescription of O. otagense (McCann) and O. waimatense (McCann). Journal of the Royal Society of New Zealand27(4), 439-450.

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

Whitaker, A. H. (1987). The roles of lizards in New Zealand plant reproductive strategies. New Zealand journal of botany25(2), 315-328.

Wotton, D. M., Drake, D. R., Powlesland, R. G., & Ladley, J. J. (2016). The role of lizards as seed dispersers in New Zealand. Journal of the Royal Society of New Zealand46(1), 40-65.