Oligosoma pikitanga, Bell, Trent P & Patterson, Geoff B, 2008

Bell, Trent P & Patterson, Geoff B, 2008, A rare alpine skink Oligosoma pikitanga n. sp. (Reptilia: Scincidae) from Llawrenny Peaks, Fiordland, New Zealand, Zootaxa 1882, pp. 57-68 : 60-67

Oligosoma pikitanga sp. nov.

( Figs. 4–10 )

Holotype. RE 5315 (juvenile male, 61 mm SVL, 75 mm tail length; Te Papa Tongawera Museum of NZ) Sinbad Gully, Llawrenny Peaks, Fiordland (44° 38'44.46'' S 167° 48'19.65'' E; New Zealand Map Grid ( NZMG) reference E2098195 N2098195, map series 260, sheet code D40.), 1100 m ASL collected by T. Jewell, March 2004 ( Figure 4 ).

Live Specimen. (1) Live adult male (82 mm SVL, 106mm tail length, 10g weight (wt)), Sinbad Gully, Llawrenny Peaks, Fiordland (44° 38'44.46'' S 167° 48'19.65'' E; New Zealand Map Grid ( NZMG) reference E2098195 N2098195, map series 260, sheet code D40) 1150 + 50 m ASL collected by T. Jewell, 10 March 2007. Figs. 5–7 .

Further Live Specimens: (2) Juvenile female (64 mm SVL, 82 mm tail length, 4.5g wt). All subsequent locality details are as for Live Specimen (1); Collected 17 February 2008. (3) Adult male (82 mm SVL, 88 mm tail length, 10.8g wt). Collected 18 February 2008. (4) Adult male (90 mm SVL, 98 mm tail length, 9mm regenerated tail portion (r) 15g wt). Collected 18 February 2008. (5) Adult female, gravid (91 mm SVL, 89 mm tail length, 48mm r, 15g wt). Collected 18 February 2008.

Diagnosis. This medium sized skink (SVL up to ˜ 91mm, 188mm total length and 15g weight) is relatively easily distinguished from all other Oligosoma species, having a characteristic appearance with large green dorsal speckles against a black dorsal base colour, a black upper-lateral band with large salmon-pink lateral speckles, a pale grey chin and a belly flushed with vivid orange. O. pikitanga has a shiny, glossy appearance, and is slender with long toes and long tail. The nearest genetically-related species are each further separated by distinct counts of mid-body scale rows ( O. pikitanga 38; O. infrapunctatum 29–37; O. otagense 46–72; O. taumakae 32–34; O. waimatense 50–68), ventral scale rows ( O. pikitanga 78–88; O. acrinasum 90– 100), subdigital lamellae ( O. pikitanga 20–23; O. acrinasum 16–19) or the relative size of the dorsal scales (in O. pikitanga smaller than ventrals; in O. infrapunctatum larger). This species is allopatric to all other genetically-related species.

Description of Holotype. Body elongate, oval in cross-section; limbs well developed, pentadactyl ( Figs. 4–7 ). Lower eyelid with a transparent palpebral disc, bordered on sides and below by small, oblong granules. Nostril centred just below middle of nasal, pointing up and back. Supranasals absent. Rostral broader than deep. Frontonasal broader than long, separated from frontal by prefrontals meeting in the midline. Frontal longer than broad, shorter than frontoparietal and interparietal together, in contact with 2 anteriormost supraoculars. Supraoculars 4, the 2nd largest. Frontoparietals distinct, larger than interparietal. A pair of parietals meeting behind interparietal and bordered posteriorly by a pair each of nuchals and temporals, also in contact with interparietal, frontoparietal, 4th supraocular and 2 postoculars. Loreals 2, similar size; anterior loreal in contact with 1st and 2nd supralabial, posterior loreal, prefrontal, frontonasal and nasal; posterior loreal in contact with 2nd and 3rd supralabial, 1st subocular, upper and lower preocular, prefrontal and anterior loreal. Supralabials 8 (left)/7 (right), the 7th/6th largest. Infralabials 6, several of them equal in size; 6th/5th supralabial below centre of eye. Mental broader but shallower than rostral. Suboculars 3 and 4 separated by 6th/5th supralabial. Postmental larger than mental. Chinshields 3 pairs. Dorsal scales not largest, weakly striate, 1 x 1.5mm. Ventral scales smooth, c 1.8 x 1.8 mm. Subdigital lamellae smooth. Nasals separate. One primary temporal scale. Forehead concave, snout slightly convex. Ear opening round, moderately large, lacking projecting granules on anterior margin. Forelimbs shorter than hind limbs, adpressed limbs overlapping in live specimen. Digits very long, cylindrical. Third front digit shorter than the 4th. Precloacal scales enlargened, c. 20; postcloacal scales 20. All scales have a glossy appearance.

Measurements (in millimeters; holotype with the Live specimen (1) in parentheses):

SVL 61 (82); HL 10 (13.3); HW 6 (8.3); AG 31 (42); SF 22 (27); SE 11 (14); EF 10 (14); FTL 6.7 (11.0); HLL 26 (34); diameter of eye 2.5 (3.0); diameter of ear 0.9 (1.8); TL 75.0 (106).

5 6 Variation (holotype with the variation shown in the Live specimen (1) in parentheses):

Upper ciliaries 7 (6); lower ciliaries 11 (10); nuchals 1 pair (1 pair); midbody scale rows 38 (38); ventral scale rows 88 (78); subdigital lamellae 23 (20); supraciliaries 7 (6); suboculars 6 (6).

Ratios for morphological measurements (holotype with the Live specimen (1) in parentheses):

AG/SF 1.4 (1.6); SE/EF 1.1, (1.0); HL/HW 1.7 (1.6). Both specimens had intact tails – ratios 1.23 (1.29).

Colour. Primary dorsal markings range from a jet black base with regular green specks, to primarily green with black mottling. Median dorsal stripe absent. Dorsolateral line absent, although intensity of green pigment along the dorsal-lateral area may form a stripe which may be distinct from the head and shoulders but break up progressively down the body. Lateral surface black with grey or pinkish spots. Primary head markings as for dorsal markings. Tail mainly green with some black flecking. Ventral surface vivid orange, shading into gray on undersurface of tail, throat and chin blackish-grey. Soles of feet black, upper and outer surface of limbs blotched with black and pink. Juvenile coloration is similar to adult, however neonate colouration is unknown.

Genetics. Genetic analyses of the Sinbad skink were undertaken by David Chapple and collaborators (D.G. Chapple, C.H. Daugherty & P.A. Ritchie, unpublished data) as part of a wider phylogenetic study of the relationship among all members of the New Zealand skink radiation. Analyses indicate that O. pikitanga is a part of a phylogeny clade containing O. acrinasum , O. infrapunctatum , O. otagense , O. taumakae ( Chapple & Patterson, 2007) and O. waimatense ( Fig. 11). Genetic distances calculated from a Neighbour-Joining (NJ) tree, with 1000 bootstraps, generated in MEGA 3.1 ( Kumar et al. 2004) by D. Chapple (pers. comm.) between O. pikitanga and other species within this clade are as follows: O. acrinasum (11.8%), O. infrapunctatum (10.8%), O. otagense (11.5%), O. taumakae (9.4%), and O. waimatense (10.2%). As a rough guide, from genetic work on other NZ skink species, the level of genetic distance between recognized species (for ND2 and ND4) is at least 7–10% (D. Chapple, pers. comm.). These genetic analyses indicate a clear species-level separation from all other New Zealand skink species, apart from an as-yetundescribed species, O. sp. "Barrier". Genetic distances between this undescribed species and O. pikitanga are only 3.0%, however the two skinks can be readily distinguished by appearance, morphology, ecology and behaviour (Patterson & Bell, in prep). Both the Sinbad and Barrier skinks appear to be the most basal and distinctive members of this clade. The ND2 and ND4 sequence data from mitochondrial DNA genes used to construct the phylogeny are available on GenBank (sequence accession numbers for ND2 are SVS1 (juvenile holotype): EU567713 and SVS3 (live specimen 1): EU885755 ; and for ND4, SVS1: EU567743 and SVS3: EU885758 (D. Chapple pers comm.)).

Etymology. The English words ‘mountain climber’ can be translated into the Maori language as ‘ pikitanga’ and is applied to this skink in reference to the species’ alpine ecology. The common name ‘Sinbad 8 9 10 skink’ has come into popular use and refers to the type locality in the Sinbad Gully, Llawrenny Peaks. The Sinbad Gully was named by Donald Sutherland (a Scottish sailor, soldier and prospector) in 1878, inspired by the legend of Sinbad the Sailor’s Valley of Diamonds (Jewell 2007).

Distribution and ecology. The type locality is the only locality record known to date for O. pikitanga . The Sinbad Gully is a north/north-west facing alpine cirque basin at the head of the Sinbad Valley at 1100m ASL, enclosed on three sides by vertical rock cliffs 150–250m high up to c. 1250m ASL, straddled by the Llawrenny Peaks (Darran Ecological District 72.01; McEwen 1987) reaching to 1925m ASL. The geology of the Llawrenny Peaks is derived of the Milford Gneiss formation ( Blattner 1991; Wood 1962) covering an area of 15km, reaching north to Mt Pembroke across Milford Sound, west to Rugged Mountain and south to Mackinnon Pass. The Milford area (LENZ Environment R2.2a; Leathwick et al 2003) consists of glaciated or partly glaciated mountain ranges up to 2,000m in altitude, dramatically shaped by successive ice-advances in the Pleistocene into U-shaped valleys with 45–90 degree walls. During the last glacial maximum (Otira Glaciation) 18–20,000 years ago, the Milford Sound glacier reached a total depth of 2.17km and extended 12.5 km ( Augustinus 1992) providing widely spaced nunataks at around 2200m ASL (I. Turnbull, pers comm.), suggesting that lizards could not have been present at this time. The last major glaciation event occurred 14,000 years ago ( Fitzsimons 1997, Fitzsimons & Veit 2001).

The climate of Environment R2.2a (as modeled from a suite of stations and extrapolated across the landscape) is very cold with mean annual temperature of 6.5 degrees Celsius and a mean minimum temperature of the coldest month of -0.7 degrees ( Leathwick et al. 2003). Actual temperatures are currently unknown for the cirque basin, however Leathwick et al. (2003) provide a suitable approximation given the species’ known altitude. The high elevation, coupled with its exposure to rain-bearing clouds and westerly winds, results in low sunshine hours of less than 1600 hours per annum ( Atkinson & Merton 2006) and a mean annual solar radiation of 12.1 MJ/m2/day, but this drops to a winter mean solar radiation of 3.1 MJ/m2/day) ( Leathwick et al. 2003). This area receives an extraordinary average annual precipitation of up to 12,000mm /y ( Griffiths and McSaveney 1983), giving rise to numerous cascading waterfalls year round and heavy snow falls during the winter. The cirque basin is snow-bound during winter and avalanche prone in the spring months. The microclimate of the cirque basin is sheltered from the prevailing westerly winds and the gneiss rock also provides thermal refugia from extreme elements.

Little is known about the biology, ecology and life-history of O. pikitanga . This new species occupies damp alpine to sub-alpine cliffs in the Llawrenny Peaks and is likely to occupy cirque basin walls and similar steep rock terrain, foraging on ledges amongst vegetation, and utilizing crevices in the rock as refugia (Bell et al. in press, Bell & Patterson (in prep)). The elongate body form, long toes and relatively high scale counts are suggestive of a saxicolous existence, typical of other saxicolous Oligosoma species, such as O. waimatense and O. grande (Gray, 1845) . The striking green colouration of this skink also suggests it has a strong association with the vegetation of the area. All but one skink have so far been discovered among pockets of vegetation on rock bluffs. As with almost all other Oligosoma species, this species is likely to be diurnal and livebearing and one individual skink was observed sunbasking (H. Edmonds, pers. comm.). The juvenile holotype was found under loose rocks at the foot of the cirque wall at 1100m ASL and five animals were found among snow tussock ( Chionochloa pallens ) vegetation on the cirque wall at 1150m + 50m ASL. Sympatric species include a putative new species ( O. sp. ‘mahogany skink’, affiliated with the cryptic skink, O. inconspicuum species-complex; Bell et al. in press; Bell & Patterson in prep, and D. Chapple, pers comm.) and the Cascades gecko (a member of the forest and alpine gecko, Hoplodactylus granulatus species-complex; Bell et al. in press and R. Hitchmough, pers. comm.).

The flora and fauna of the Sinbad Gully are species-diverse. The flora is adapted for alpine and sub-alpine areas, particularly for (1) rocky cliffs and areas and/or (2) snow accumulation during the winter. These include alpine tussock ( Chionochloa pallens , C. ovata and C. crassicula ), ferns ( Blechnum spp., kiokio), whipcord hebes ( Hebe spp), pohuehue ( Muehlenbeckia axillaris ), Coprosma and snowberries ( Gaultheria spp.), Dracophyllum spp, mountain daisies ( Celmisia hectorii , tikumu) and lily ( Astelia spp.), mountain buttercup ( Ranunculus lyallii ) and snow marguerite ( Dolichoglottis scorzoneroides ). Other plants present are Aciphylla spp. and the native broom (Carmichaeli) (K. Lloyd, pers. comm.). The skink has a strong association with the vegetation as all captures (both by hand and trap) were within vegetation and not on bare rock surfaces. These skinks are likely to forage within vegetation and utilize this vegetation as refugia.

The fauna of the Sinbad Gully include the rock wren ( Xenicus gilviventris ), kea ( Nestor notabilis ), New Zealand falcon ( Falco novaeseelandiae , karearea) and weka ( Galliralus australis ).

Ecological and ecophysiological studies of this skink, the Barrier skink, ( O. sp. ‘Barrier’), and the Fiordland skink, ( O. acrinasum ) would provide a valuable insight into how these skinks survive such contrasting yet extreme environments.

100 Oligosoma infrapunctatum (OIF1)

Oligosoma infrapunctatum (OIF2)

100 Oligosoma otagense (OOT1)

62 Oligosoma otagense (OOT2)

100 Oligosoma taumakae (OBI2)

Oligosoma taumakae (OBI3)

70

100 Oligosoma acrinasum (OAC1)

Oligosoma acrinasum (OAC3)

93 Oligosoma waimatense (OWA2)

100 Barrier Skink (BKS1)

100 Barrier Skink (BKS2)

100 Oligosoma pikitanga (SVS1)

Oligosoma pikitanga (SVS3)

Oligosoma smithi (OSM1)

Oligosoma zelandicum (OZE3) 55 Cyclodina oliveri (COL1)

Oligosoma n polychroma (ONP1) 0.01 Conservation status. Oligosoma pikitanga (as O. sp. 'Sinbad Gully') is a threatened species currently listed by the New Zealand Department of Conservation as DD, OL (data deficient, one location) (Hitchmough et al. 2007) based on the type population. A recent DOC meeting ( Henderson 2007) and report (Bell et al. in press) have also since classified the species as being of regional high priority and as requiring urgent surveys, research, and conservation action.

It is concerning that only six specimens of this species have been discovered, despite four recent lizard surveys from 2004 to 2008. Rock climbers over recent years have found many geckos but no skinks around the 200m high ‘Shadowland’ wall, which forms a large part of the cirque bluffs on which this skink exists ( Jewell & Morris 2007). Detailed faunal and floral surveys in extensive rocky and vegetation habitat throughout the Sinbad Gully environment during the 1970's also found no evidence of skinks (R. Morris pers. comm.; D. Merton pers. comm.).

The known habitat is protected within a National Park, but invasive mammalian predator control is not currently undertaken within the known range for these skinks. Recent accounts of mice ( Mus musculus ) and possums ( Trichosurus vulpecula ) indicate the presence of mammals in the area (Bell et al in press). Native predators may be the weka ( Galliralus australis ) and kea ( Nestor notabilis ).

A similarly-sized sister species, the Fiordland skink, O. acrinasum , is extant along the harsh littoral rock areas of the south-western Fiordland coastline ( Hardy 1977) almost exclusively on islands free of introduced mammalian predators ( Thomas 1985a & b). Given both skinks’ close relationship to each other, similar morphology and occupation of similarly extreme environments, Oligosoma pikitanga may have experienced similar severe range constrictions as a result of potentially similar predator pressure, particularly from mice, rats and stoats; the insofar observed cliff-dwelling behaviour of this skink may in fact be an artifact of current introduced mammalian predator pressure.

Figures

FIGURE 4. Sinbad skink (Oligosoma pikitanga) holotype (RE 5315) photographed at the head of the Sinbad Gully, March 2004. Note the particularly long toes. Photograph: Rod Morris

FIGURES 5, 6. Dorsal and ventral views of the Sinbad skink (Oligosoma pikitanga, Live specimen 1) from the head of the Sinbad Gully, March 2007. Photographs: Trent Bell

FIGURE 7. Sinbad skink Live specimen 1 displaying full body detail in natural surroundings, Sinbad Gully, March 2007. Note the large green speckles and elongated tail. Photograph: Rod Morris

FIGURES 8 – 10. Head and chin drawings of O. pikitanga (note the lateral drawing is from Live Specimen, due to the poor condition of the lateral head side of the Holotype).