Oligosoma judgei, Patterson, Geoff B & Bell, Trent P, 2009

Patterson, Geoff B & Bell, Trent P, 2009, The Barrier skink Oligosoma judgei n. sp. (Reptilia: Scincidae) from the Darran and Takitimu Mountains, South Island, New Zealand, Zootaxa 2271, pp. 43-56 : 46-49

Oligosoma judgei sp. nov. ( Figs. 4–5 )

Holotype. RE6878 Te Papa Tongarewa Museum of NZ; Barrier Knob, Darran Mountains, Fiordland; 44° 38’20.00” S 168° 01’30.00” E at 1600m ASL; adult male, 80.5 mm SVL, 87.4 mm tail length of which 4.5 mm was regrown, coll. T. Bell, March 2008 ( Figure 4 ).

Paratype: RE4126 Te Papa Tongarewa Museum of NZ; Students Peak, Earl Mountains, Fiordland; no available latitude/longitude co-ordinates; coll. T. Choate, 1966.

Live Specimens. Four live specimens, Barrier Knob, Darran Mountains, Fiordland, 1600 m ASL collected by T. Jewell and T. Bell, February 2007. Tail tip tissue samples from two animals collected by T. Bell, February 2007. An additional four live specimens collected by T. Bell, T. Jewell, P. Lei and H. Edmonds, same location, February and March 2008 ( Figure 5 ).

Diagnosis. Oligosoma judgei can be distinguished from all congeners by a combination of characters. The coloration is similar only to O. grande , O. waimatense and O. acrinasum . O. judgei has fine green or yellow dorsal speckles against a black dorsal base colour, a black dorso-lateral band with green or yellow lateral speckles, and a white ventral surface speckled occasionally with black. In O. waimatense dark blotches on the dorsal surface are made up of smaller spots forming transverse bands – no such patterning is evident in O. judgei . The maximum SVL of O. judgei is significantly less than for O. grande , O. waimatense and O. otagense . The ear opening is approximately 32% wider than in O. grande (SVL/ear diameter = 44 in O. grande [n=4], O. judgei holotype = 58 [diameter could not be measured accurately in paratype]), and separated from primary temporal by 6 scale rows in O. judgei vs 4 scale rows in O. grande . The nearest genetically-related species are each further separated by distinct counts of mid-body scale rows ( O. judgei 44– 50 vs O. pikitanga 38; O. infrapunctatum 29–37; O. taumakae 32–34; O. acrinasum 37–38), ventral scale rows ( O. judgei 90–97 vs O. pikitanga 78–88), subdigital lamellae ( O. judgei 24–25 vs O. pikitanga 20–23; O. acrinasum 16–19) and the relative size of the dorsal scales ( O. judgei smaller than ventrals vs larger in O. infrapunctatum ).

We now consider in greater detail differentiation from O. pikitanga which is genetically very similar to O. judgei (see below). Morphological evolution and molecular evolution are often not closely linked in the New Zealand lizard fauna and there are numerous examples of cryptic species (similar morphology, but genetically distinct) and ‘morphological’ species (morphologically distinct, but genetically similar) ( Hitchmough 1997; D. Chapple pers comm. 2008). Two examples of the latter are H. kahutarae , which is genetically a very close sister species to H. granulatus , yet morphologically and ecologically very distinct, and the genus Naultinus , for which genetic diversity is so shallow that some proponents have suggested that the seven recognised taxa are conspecific ( Hitchmough 1997; Chambers et al 2001; Hitchmough 2008). However in Naultinus , morphological differences strongly support retaining the presently recognised species ( Hitchmough 1997, 2008).

This situation has arisen largely because of the geological upheaval and climatic stresses that have occurred in New Zealand, resulting in high geographical and ecological diversity, giving way to rapid bursts of speciation in the lizards ( Slack et al 1995; Hickson et al 2000; Chambers et al 2001). The recent geological and climatic challenges of the Fiordland region indicate fast speciation is likely to occur even with relatively slow corresponding genetic changes. Such appears to be the case with O. pikitanga and O. judgei .

Oligosoma judgei differs morphologically, ecologically and behaviourally from O. pikitanga in several significant aspects ( Table 1 ). We consider such differences to be very unlikely within one species across two populations that are in such close proximity (closest known populations c. 20 km apart) and at similar altitude to each other. However, we acknowledge that there is a possibility, given that the two closest sites are contiguous but separated by the formerly glaciated Arthur River Valley, of a cline connecting the two species. Surveys throughout the area separating the two species should be a priority.

judgei and the Sinbad skink, O. pikitanga .

Genetics 3% genetic differentiation between the two species (D. Chapple, pers. comm. 2008)

Appearance Dull Glossy sheen

Body Proportions Stout Slender

Colour Black with fine green, brown or yellow flecks, Black or green with large green black dorso-lateral band with speckles white speckles, salmon pink lateral sides, belly, speckled occasionally with black belly flushed with orange

SVL and tail Similar size and ranges, reaching up to 91mm SVL and 190mm total length

Morphometrics

TL/SVL ratio 1.08 1.23–1.29

(intact) 14.7g, ra. 14–15.4g Up to 15g

Wg 1.3–1.5 1.6–1.7

HL/HW ratio 44–50 38

Midbody scale row 90–97 78–88

Ventral scale row 24–25 20–23

Lamellae Similar to postmental Smaller than postmental

Mental scale Widely, or moderately widely separated Narrowly separated

Nasals

a. Data from Bell & Patterson (2008).

Figures

FIGURE 4. Barrier skink (Oligosoma judgei) holotype (RE 6878). Photograph: Trent Bell

FIGURE 5. Dorsal and ventral views of (top to bottom) Barrier skink, Sinbad skink, Barrier skink, Sinbad skink. Photographs: Trent Bell

Tables

TABLE 1. Comparison of ecological, behavioural, genetic, phenotypic and morphometric features identified between O.

Character	O. judgei	O. pikitanga a
Ecological	Clean rocky cliffs, not strongly associated with vegetation	Damp cliffs, strongly associated with vegetation
Behaviour	Bold, avid sun-basker	Extremely shy, rarely visible
Altitude	High altitude zone (1250–1600 m ASL, potentially up to 1800m)	Mid-altitude zone (1100 m ASL)