Oligosoma oliveri (MCCANN, 1955)
Can you confirm these amateur observations of Oligosoma oliveri?
|Higher Taxa||Scincidae, Eugongylinae, Scincoidea, Sauria, Squamata (lizards)|
|Common Names||Marbled Skink, Oliver's New Zealand Skink|
|Synonym||Leiolopisma oliveri MCCANN 1955|
Leiolopisma oliveri — GREER 1974: 16
Leiolopisma oliveri — ROBB 1975
Cyclodina oliveri — HARDY 1977
Cyclodina oliveri — WELLS & WELLINGTON 1985
Cyclodina oliveri — HICKSON et al. 2000
Oligosoma oliveri — PATTERSON & BELL 2009
Oligosoma oliveri — CHAPPLE et al. 2009
|Distribution||New Zealand (Poor Knights Islands off the east coast of Northland)|
Type locality: Poor Knights Island, Northern Islet (= Tawhiti Rahi) (35° 28’ S, 174° 44’ E).
|Types||Holotype: NMNZ R153, adult female|
|Diagnosis||DIAGNOSIS: Cyclodina oliveri can be distinguished from all other C:Vclodina species through a combination of characters. Cyclodina oliveri has a prominent teardrop marking under the eye and >= 4 midbody scale rows, distinguishing it from C. aenea, C. aenea "Te Paki", and C. aenea "Poor Knights Islands". Cyclodina oliveri has an unbroken subocular scale row, distinguishing it from C. aenea "Poor Knights Islands". The genetic results indicate that C. oliveri is closely related to C. whitakeri; however, it can be distinguished through several morphological characters, predominantly coloration and scale counts. Cyc!odina oliveri lacks the yellow and orange coloration of many C. whitakeri specimens (Hardy 1977). Cyc!odina oliveri (TLlSVL: 1./1) has a shorter tail than C. whitakeri (TLlSVL: 1.2; Hardy 1977). Although there is overlap in midbody scale counts between C. oliveri (4-42) and C. ornata (28-7; Hardy 1977), the coloration differs between these two species. Colour pattern distinguishes C. oliveri from C. macgregori and C. alani, with C. alani having a more robust body form and greater maximum SVL.|
Diagnosis. An Oligosoma with a squarish mid-body cross-section; opaque, divided palpebral disc; a prominent tear-drop mark beneath each eye; iris light brown to orange; mid-body scale rows 37–44; ventral scale rows 88–97; eye diameter < distance from the eye to mouth; adult SVL ≥ 90 mm; dorsal markings dominated by pale blotches or mottling; belly cream and markings form broad blotching. Distinguished from similar congeners (which share both the squarish body cross-section and the tear-drop subocular marking) as follows: alani (Robb) has a black iris, much larger dorsal blotches and is bulkier, up to 142 mm SVL; macgregori (Robb) has longitudinal streaks on the dorsum and a uniform belly; ornatum (Gray) is much smaller (SVL usually < 80 mm), usually has a yellow belly and usually has a tapering pale dorso-lateral stripe; pachysomaticum has 32–36 mid-body scale rows, 72–88 ventral scale rows, dorsal and ventral patterns dominated by dark flecks, and a larger eye (diameter > distance from eye to mouth); roimata (Patterson, Hitchmough & Chapple) (sympatric) is much smaller at up to 65 mm SVL, has only 32–34 mid-body scale rows and 1 primary temporal scale (versus 2 in oliveri); townsi usually has only 1 primary temporal scale and few ventral markings; and whitakeri has a dark-brown iris, yellow-orange venter and dorsal and ventral patterns of dark flecks [Jewell 2019: 391].
|Comment||Abundance: Rare, threatened, or endangered species.|
Synonymy: Leiolopisma pachysomaticum ROBB 1975, previously a synonym of O. oliveri, was revalidated by Jewell 2019.
Habitat: Lives primarily among leaf litter on the floor of coastal forest and scrub, utilizing a range of cover objects and sea bird burrows as retreat sites, and is crepuscular with peaks of activity after dusk and before dawn. Gravid females occasionally bask but the species is normally otherwise inactive by day (Jewell 2019).
Illustration: in BioGecko 3: 72 (by Trent Bell).
Cyclodina oliveri and C. townsi are very difficult to distinguish morphologically. This is chiefly because the scale counts for C. oliveri on the Poor Knights overlap greatly with those for C. townsi, as noted by Hardy (1977). However, the Poor Knights skinks are so distinctive, in terms of coloration, body size and scalation, that it is not surprising that Hardy (1977) thought that there might be two subspecies within what is now classified as C. oliveri. The Poor Knights skinks are larger and more strikingly coloured than the C. oliveri from other islands, and their scale counts are significantly higher. Cyclodina townsi and C. oliveri can be distinguished only by a combination of colour pattern and temporal scale counts.
|Etymology||named after the collector of the type, W.R.B. Oliver (1883–1957), former director of the Dominion Museum (now Museum of New Zealand/Te Papa Tongarewa) in Wellington, New Zealand.|