McGregor’s skink (Oligosoma macgregori)

Also known as: Macgregor’s skink
Synonyms: Cyclodina macgregori
KingdomAnimalia
PhylumChordata
ClassReptilia
OrderSquamata
FamilyScincidae
GenusOligosoma (1)
SizeSnout-vent length: up to 11.2 cm (2)

Classified as Vulnerable (VU) on the IUCN Red List (3).

One of New Zealand’s rarest lizards, McGregor’s skink is a medium-sized and secretive reptile (4), with a long body, short but well-developed limbs, and smooth, shiny scales (2) (5). The back is light yellowish-brown, with irregularly broken, darker stripes running from the neck to the base of the tail, and in some individuals onto the tail itself (2) (6). The underside of the body and the inner surface of the limbs are grey, cream or light pink, often with darker flecks, and a dark patch containing yellowish areas extends from behind the ear to just level with the forelimbs. The eyes are relatively small compared to other related species, and may be marked underneath with a pale, black-edged ‘tear drop’ (2) (6). Previously classified within the genus Cyclodina, recent molecular evidence suggests that McGregor’s skink, together with all native New Zealand skinks, should be placed within a single genus, Oligosoma (1).

McGregor’s skink is endemic to New Zealand, where it has an extremely fragmented distribution, being found only on Motuharakeke Island in the Cavalli Islands, Mauitaha Island in the Outer Bream Islands, Sail Rock in the Hen and Chickens Islands, and Mana Island, near Wellington (2) (4) (7). Populations have also been translocated to Lady Alice and Whatupuke Islands (7) (8).

Inhabits mainly coastal scrub or forest, often in areas that have been heavily burrowed by sea birds (7). McGregor’s skink usually shelters by day under rocks and logs, or amongst leaf litter, and is often found in bouldery areas, where it is protected from extremes of temperature and where moisture levels are high (4) (7).

Little is known about the biology of McGregor’s skink, though it is likely that, like other skinks, it feeds mainly on insects (5) (9). Individuals are usually active in the early morning and late evening (7), and may be quite aggressive in defence of preferred sites (4). McGregor’s skink is ovoviviparous, meaning the developing eggs hatch inside the female, the female then giving birth to live young. Usually only two young are born at a time, in late summer or early autumn (February to March). McGregor’s skink takes up to four or five years to reach adult size, and may live for over ten years (4).

Once far more widespread, including on mainland New Zealand, McGregor’s skink is now restricted to a few islands that are free of mammalian predators such as mice, to which the whole of the genus are believed to be vulnerable (4) (7). The possibility of such predators reaching these islands is probably the greatest threat to the remaining populations of McGregor’s skink. Habitat disturbance is now unlikely to be affecting McGregor’s skink (8), although past road construction may have reduced available shelter (4). The species’ vulnerability to heat stress and to water loss through the skin may also restrict it to habitats with high humidity and protection from temperature extremes (7). The relatively low reproductive rate typical of New Zealand skinks (10) may mean that populations take a long time to recover from any losses.

McGregor’s skink has been included in a recovery plan, published in 1999, which sets out objectives for the conservation of this and other related skinks (7). Conservation measures already in place include the translocation of groups of McGregor’s skinks as part of the planned restoration of two islands from which introduced rodents have been removed. Other translocations have also been proposed, with the short-term aim of increasing the number of populations and expanding the area the species occupies. Eradication of rodents and other introduced predators from other islands is ongoing, and the future of the remaining populations of McGregor’s skink will also rely on preventing these predators from reaching the skink’s last few island strongholds (4) (7). An incursion of ship rats was discovered on Lady Alice and Whatupuke Islands in early 2009, but the rats have since been eradicated (8). There also needs to be careful consideration of any proposed introductions of native species, such as the weka, Gallirallus australis, which may prey on the vulnerable McGregor’s skink population (4).

For more information on the conservation of McGregor’s skink and other New Zealand lizards, see:

New Zealand Department of Conservation - Cyclodina skink:
http://www.doc.govt.nz/conservation/native-animals/reptiles-and-frogs/lizards/cyclodina-skink/

New Zealand Herpetological Society:
http://www.reptiles.org.nz/

For more information on ecological restoration projects taking place on Mana Island, New Zealand, see:

Friends of Mana Island:
http://www.manaisland.org.nz/index.htm

Authenticated (29/04/09) by Dr David Towns, New Zealand Department of Conservation.

  1. Chapple, D.G., Ritchie, P.A. and Daugherty, C.H. (01/01/0001 00:00:00) Origin, diversification, and systematics of the New Zealand skink fauna (Reptilia: Scincidae). Molceular Phylogenetics and Evolution,.
  2. Hardy, G.S. (1977) The New Zealand Scincidae (Reptilia: Lacertilia): a taxonomic and zoogeographical study. New Zealand Journal of Zoology, 4: 221 - 325.
  3. IUCN Red List (February, 2009)
    http://www.iucnredlist.org/
  4. Newman, D.G. (1994) Effects of a mouse, Mus musculus, eradication programme and habitat change on lizard populations of Mana Island, New Zealand, with special reference to McGregor’s skink, Cyclodina macgregori. New Zealand Journal of Zoology, 21: 443 - 456.
  5. Halliday, T. and Adler, K. (2002) The New Encyclopedia of Reptiles and Amphibians. Oxford University Press, Oxford.
  6. Chapple, D.G., Patterson, G.B., Bell, T. and Daugherty, C.H. (2008) Taxonomic revision of the New Zealand copper skink (Cyclodina aenea: Squamata: Scincidae) species complex, with descriptions of two new species. Journal of Herpetology, 42(3): 437 - 452.
  7. Towns, D.R. (1999) Cyclodina Spp. Skink Recovery Plan 1999-2004. Threatened Species Recovery Plan 27. Department of Conservation, Wellington, New Zealand.
  8. Towns, D.R. (2009) Pers. comm.
  9. Burton, M. and Burton, R. (2002) International Wildlife Encyclopedia. Third Edition. Marshall Cavendish, New York.
  10. Cree, A. (1994) Low annual reproductive output in female reptiles from New Zealand. New Zealand Journal of Zoology, 21: 351 - 372.