Caledoniscincus pelletieri, Sadlier, Ross A., Whitaker, Anthony H., Wood, Perry L. & Bauer, Aaron M., 2014

Sadlier, Ross A., Whitaker, Anthony H., Wood, Perry L. & Bauer, Aaron M., 2014, A new species of lizard in the genus Caledoniscincus (Reptilia: Scincidae) from far northwest New Caledonia, Zootaxa 3795 (1), pp. 45-60 : 50-57

Caledoniscincus pelletieri sp. nov. Sadlier, Whitaker, Wood & Bauer

Figs. 1–5

Holotype. MNHN 2012.0225 (formerly AMS R.174984) Dôme de Tiébaghi (southwest end of plateau), Province Nord, New Caledonia 20°28'20"S 164°12'43"E (collected 23 November 2011, A.H. & V.A. Whitaker).

Paratypes. All Province Nord, New Caledonia: AMS R.174994 Dôme de Tiébaghi (southwest end of plateau) 20°28'30"S 164°12'47"E (collected 24 November 2011, A.H. & V.A. Whitaker); AMS R.177490 Dôme de Tiébaghi (northern end of plateau) 20°26'18"S 164°11'42"E (collected 2 November 2012, S. Astrongatt); AMS R.177491 Dôme de Tiébaghi (southern end of plateau) 20°28'26"S 164°13'44"E (collected 5 November 2012, S. Astrongatt).

Etymology. The species is named after Bernard Pelletier, formerly head of environment for Société le Nickel (SLN), Nouméa, in recognition of his exceptional support to herpetological surveys of mining areas commissioned by SLN and undertaken by Whitaker Consultants Limited (AHW).

Diagnosis. Caledoniscincus pelletieri sp. nov. can be distinguished from the other species of Caledoniscincus by the following combination of characters: (a) body size moderately large (largest of four adult females 58.5 mm SVL); (b) lamellae of fourth toe 35–37; (c) midlateral stripe broad, pale, extending between fore and hind limbs only; and (d) ventral colour bright yellow.

Only three other species of Caledoniscincus , C. constellatus , C. haplorhinus and C. austrocaledonicus (northern and central region populations, see Sadlier et al. 1999), have a pale lateral stripe along the lateral side of the body. However, in these taxa the pale mid-lateral stripe also extends along the neck between the forelimbs and ear opening (complete and unbroken in C. constellatus and C. haplorhinus , but broken in C. austrocaledonicus ), whereas the mid-lateral stripe is absent from the neck of C. pelletieri sp. nov. The general colour pattern of the body of Caledoniscincus pelletieri sp. nov. is most similar to C. constellatus and C. haplorhinus . The females of all three taxa are distinctly two-toned with a light coloured dorsal surface that contrasts markedly with the adjacent darker upper lateral surface, which in turn, is bordered below by a pale midlateral stripe along the side of the body. The ventral colour of Caledoniscincus pelletieri sp. nov. is most similar to C. constellatus in that females of both species have a bold yellow ventral surface, whereas the ventral colour is paler in adult female C. austrocaledonicus (moderate yellow), and even more so in C. haplorhinus (pale yellow).

Caledoniscincus pelletieri sp. nov. is further distinguished from C. constellatus , C. haplorhinus and C. austrocaledonicus in having more lamellae (>35 vs <35) under the 4th toe of the foot ( Table 1 ).

Description. The species is described from four adult females 45–58mm SVL.

Measurements: axilla–groin distance 55.6–63.2% SVL (x = 59.8%); forelimb–snout distance 32.5–37.8% SVL (x = 35.2%); hindlimb length 42.7–48.1% SVL (x = 44.8%); tail length of individual with original tail 195.8% SVL.

Scalation: Dorsal body scales with three strong keels; midbody scale rows 28–32 (x = 30.0, sd = 1.6); dorsal scale rows 63–65 (x = 64.0, sd = 0.8); scales on top of fourth finger 10–11 (x = 10.75 sd = 0.5); lamellae beneath fourth finger 16–18 (x = 17.25, sd = 0.65); scales on top of fourth toe 17–18 (x = 17.75, sd = 0.3); lamellae beneath fourth toe 35–37 (x = 36.1, sd = 0.85).

Osteology: Premaxillary teeth 11 (n = 2); presacral vertebrae 29 (n = 2) – 30 (n = 1); postsacral vertebrae 58 (n = 1) for the only individual with original tail; phalangeal formula for the manus 2.3.4.5.3 and pes 2.3.4.5.4.

Colour and pattern – in life ( Fig. 2 a & 2b): Dorsal surface of adult females pale grey-brown above with a series of small, dark brown blotches spaced along the vertebral line of the neck, body and base of tail, with the posterior edges of the dark markings tending to extend back into the intervening lighter grey-brown areas and to become progressively more continuous, joining around the level of the hindlimbs to form an uneven-sided dark streak along the tail. The top of head is uniformly pale grey-brown and without darker markings. Lateral surface of body between the fore and hind limbs very dark brown divided by a bold white mid-lateral stripe that extends along the side of the body between the limbs. White mid-lateral stripe terminates abruptly at the anterior end just above the insertion of the forelimb, but extends posteriorly beyond the hind limbs and onto the tail, and less distinctly down the leading edge of the front and hind limbs. Lateral surface progressively changes tone from dark to mid-brown on the neck and face, and lacks obvious white markings. Dorsal and lateral surfaces well differentiated and highly contrasting, with the dorsolateral edge irregular, and sometimes (paratype) defined by a pale (cream) narrow stripe between the eye and along the remainder of the body (half scale width). Lateral and ventral surfaces also highly contrasting (changing from dark brown to bright yellow) and well differentiated. The hind limbs of smaller individuals have a russet suffusion above and at the sides. Tail grey-brown above, with the darker vertebral markings on the body, continuing along the tail as a series of interconnected mid-brown blotches. Lateral surface of tail dark over the remainder of its length. Under-surface of the head and neck predominately white but with fine dark brown markings at the side that extend diffusely and irregularly onto the lower surface of head and neck, remainder of body posterior of the forelimbs bold yellow which also extends along the underside of the limbs to the soles and along the proximal third of the tail. Soles of feet grey.

Details of Holotype: Adult female (MNHN 2012.0225); size 58.5 mm SVL; tail incomplete, length 103 mm (19.5 mm of tip reproduced).

Comments. The colouration of female Caledoniscincus pelletieri sp. nov. is similar to that of the single known adult female of its’ sister taxon C. constellatus in having a highly contrasting grey-brown dorsal surface and very dark brown lateral surface to the body, a pattern of dark blotches along the vertebral line of dorsal surface, a bold white mid-lateral stripe to the body, a bold yellow flush to the underside of the body and tail, and to a lesser extent a russet flush to the upper surfaces of the limbs.

The colouration of a single male Caledoniscincus pelletieri sp. nov. photographed on Dôme de Tiébaghi ( Fig. 2 c) is similar to that of adult males of its’ sister taxon C. constellatus in having a reticulate pattern of narrow, bicoloured transverse bars on the dorsal surface of the body, the individual scales of which are black with one to several small white spots within the scale, on a predominately mid-brown background.

The most obvious difference in colouration between the two species (both males and females) is in the absence of a white mid-lateral stripe anterior to the forelimb in C. pelletieri sp. nov. Other differences in colouration between the available specimens of these two taxa include a progressive gradation in tone on the side of the head and neck from mid-brown anteriorly to dark brown approaching the forelimb in adults of both sexes in C. pelletieri sp. nov., whereas the neck is uniformly black on either side of the white mid-lateral stripe in adults of both sexes in C. constellatus . Also, the pale narrow dorsolateral edge is poorly defined or absent in adult female C. pelletieri sp. nov., whereas this marking is clearly defined and 1/2 scale wide in the female C. constellatus .

Distribution and biology. Caledoniscincus pelletieri sp. nov. is known only from the ultramafic massif of Dôme de Tiébaghi in the far northwest of the Grande Terre ( Fig. 3 ). Three individuals were captured at the southern end of the summit plateau and one approximately five kilometres distant at the northern end of the plateau ( Fig. 5 ). All sites were at or just below the plateau rim at elevations between 420– 500 m.

All specimens were captured during the day in glue traps set on the ground in stick litter. No other individuals were observed. The habitat at three sites comprises small remnants of low, closed forest that are surrounded by fireinduced maquis shrubland; at the fourth site the lizard was captured in woody maquis in sparse Araucaria rulei forest. The holotype was captured on the margin of a vehicle track through low forest (6–8 m canopy height) on cuirasse, similar to that illustrated in figure 4a; one paratype (AMS R.174944) was in a steep-sided gully within dense forest (canopy c. 15 m, trunks to 0.5 m dbh) with a thick understorey of palms as illustrated in figure 4b.

Between 2001–2012 six detailed surveys of the lizard fauna were conducted on and around the Dôme de Tiébaghi, using a variety of methods and at a large number of locations that covered the full range of habitats and elevation. Despite this level of survey effort the only specimens of Caledoniscincus pelletieri sp. nov. are those from two separate surveys in 2011 and 2012, and two recent specimens collected (and released) in 2013, it would appear that the species could be both uncommon and localized in distribution in comparison to other members of the genus.

The two female specimens collected in November 2011 both showed evidence of reproductive activity. The larger individual (holotype— 58.5 mm) contained two large shelled eggs and the smaller (AMS R.174994—52.0 mm) had three enlarged ovarian follicles (1 left and 2 right) and an enlarged and convoluted oviduct indicating it was reproductively mature. The two female specimens collected in November 2012 were smaller; one (AMS R.177491— 47.5 mm) had 2 enlarged ovarian follicles (1 left and 1 right) and in the other (AMS R.177490—45.0 mm) the follicles were not enlarged.

Other Caledoniscincus species syntopic with Caledoniscincus pelletieri sp. nov. on the Dôme de Tiébaghi plateau are C. aquilonius , C. atropunctatus , C. austrocaledonicus , C. haplorhinus and C. festivus .

Conservation status. Caledoniscincus pelletieri sp. nov. is exposed to range of human-mediated impacts of which the greatest threat comes from the expansion of the nickel mine on the Dôme de Tiébaghi plateau. Open-cast mining already occurs in very close proximity to all four sites at which this species has been found ( Fig. 5 ), abutting the forest remnants on the southwest end of the plateau and to within 100 m of the collection sites at which the species was discovered in 2011, to within 200 m of the site at the southeast end of the plateau, and to within 250 m of the site at the northern end of the plateau. Even beyond the present area of active mining, the forest and adjacent maquis is extensively tracked. Any expansion of the mine beyond the present mine footprint, or the construction of infrastructural facilities such as tracks or silt-traps within forest and shrubland areas, will result in the destruction and further fragmentation of habitat of Caledoniscincus pelletieri sp. nov.

However, even without further expansion of the mine the species’ habitat is at continued risk of degradation from mining activities. The strong winds that sweep over the plateau carry large volumes of wind-borne dust for considerable distances into the forest where it blankets the foliage and forest floor, and forest within gullies is at considerable risk to erosion and slips from accelerated water run-off redirected from the mine. The extent and quality of forest habitat on the upper part of the massif are also at risk from the wildfires that are commonplace on the slopes of Dôme de Tiébaghi in the dry season. Introduced deer and pigs, both of which are common on the massif, cause damage to forest through browsing and soil and litter disturbance, thus limiting regeneration and opening the forest to increased drying.

Other introduced species present in the forests on the Tiébaghi massif that are a threat to Caledoniscincus pelletieri sp. nov. include rodents, feral cats and invasive ants ( Wasmannia auropunctata and Anoplolepis gracilipes ). Rodents and cats are known to be important predators of lizards ( Whitaker 1978; Towns et al. 2006; Bonnaud et al. 2011; Medina et al. 2011) but distinguishing their relative impacts is difficult because of interactions between them and data on the degree to which they affect New Caledonian skink populations are lacking. However, the impacts of Wasmannia on lizards are better understood and reported as having a severe deleterious effect on the abundance and diversity within lizard communities, including the species of Caledoniscincus ( Jourdan et al. 2001) .

The population size and dynamics of Caledoniscincus pelletieri sp. nov. are not known and cannot be estimated from the data available, and as such its conservation status is derived from its extremely restricted range and the immediate threats to the species identified above. On this basis, C. pelletieri sp. nov. would satisfy the criteria to be ranked as Critically Endangered on IUCN Red List criteria (IUCN 2001).

Dôme de Tiébaghi is a highly significant site for lizard conservation. At least 21 species are known from the area including a number of Critically Endangered taxa, the majority of which are endemic to the massif. In addition to Caledoniscincus pelletieri sp. nov., these Critically Endangered taxa are: Dierogekko nehoueensis Bauer, Jackman, Sadlier & Whitaker , Oedodera marmorata Bauer, Jackman, Sadlier & Whitaker , an undescribed taxon in Bavayia , and the skink Marmorosphax taom Sadlier, Smith, Bauer & Whitaker. Two Endangered taxa with restricted distributions in northern Grande Terre and the Iles Belep, Mniarogekko jalu Bauer, Whitaker Sadlier & Jackman , and Kanakysaurus viviparus Sadlier, Whitaker, Bauer & Smith , also occur on the massif. Further, the Tiébaghi massif is the northernmost limit of range of four other lizard species, Rhacodactylus auriculatus (Bavay) , Caledoniscincus aquilonius , Lioscincus novaecaledoniae (Parker) , and Tropidoscincus boreus Sadlier & Bauer.

The establishment and management of appropriate reserves on Dôme de Tiébaghi is crucial to the long-term conservation of this diverse lizard fauna. Areas of habitat that include one of the sites from which C. pelletieri sp. nov. is known have been identified as potential conservation areas by Société le Nickel, but management of these areas should also include strategies to combat the threats to habitat identified above.

Comparative material examined. The following specimens were used in the morphological comparisons presented in Table 1 . We take here the opportunity to correct site co-ordinates for the types of Caledoniscincus constellatus presented in the original description (Sadlier et al. 2012) due to incorrect conversion from UTM coordinates to latitude and longitude.

Caledoniscincus haplorhinus : AMS R.144257–58, R.144284–86, 144288 Grottes de Koumac, 9km E of Koumac 20°33'18"S 164°21'49"E; AMS R.171480–81 Pointe de Vavouto 21°00'40.3"S 164°41'07.9"E; AMS R.171483 Pointe de Vavouto 21°00’36.4”S 164°41’8.6”E; AMS R.171491 Pointe de Vavouto 21°00’ 17.8S 164°46’ 7.5E; AMS R.146459–68, Pindaï, Plage de Pindaï 21°21'26"S 164°57'11"E; AMS R.146433–4, CAS 198763–69, 198770–71 Plage de Ouano 21°50'43"S 165°48'33"E; AMS R.77409, R.77427, R.77429, R.77437, R.77451–52, R.78319–20, R.78322, R.78326, Nouméa, Fambourg Blanchot 22°18'S 166°27'E; AMS R.135119–23 Nouville, Isle Nou 22°16'S 166°24'E.

Caledoniscincus constellatus : MNHN 2011.0228 Pointe de Vavouto 21°00'29.9"S 164°41'16.1"E; AMS R.171471 & 171496 Pointe de Vavouto 21°00'24.6"S 164°41'13.8"E; AMS R.171470 Pointe de Vavouto 21°00'30.4"S 164°41'19.7"E.

Caledoniscincus austrocaledonicus : 28 specimens as listed by Sadlier et al. (1999) from the neotype locality of Mt. Aoupinié.

Figures

FIGURE 2. Holotype (MNHN 2012.0225) of Caledoniscincus pelletieri sp. nov. an adult female (A), paratype AMS R. 174994 an adult female (B), and an adult male, no voucher (C).

FIGURE 3. Distribution of Caledoniscincus pelletieri sp. nov. (green dot) and its sister species Caledoniscincus constellatus (red square) in north-west New Caledonia.

FIGURE 5. Hypsometric relief map of Dôme de Tiébaghi (A), with sites of known occurrence of Caledoniscincus pelletieri sp. nov. (green dots). Note the isolation of massif by virtue of the low elevation terrain to the north, east and south, the extent of the peridotite (green overlay—note elevational shading applies only within this area); and satellite image of the massif (B) showing the known sites of occurrence (green dots) in relation to the proximity of active mining activity as indicated by the presence of roads and areas of exposed red laterite soils.

FIGURE 1. A Maximum Likelihood (- lnL 5966.829630) tree for the phylogenetic relationships of Caledoniscincus pelletieri relative to each species within the genus—Bayesian posterior probabilities and ML bootstrap support values are presented respectively. The new species is highlighted in grey for clarity. “ R ” numbers are associated with Australian Museum (AMS) specimens.

FIGURE 4. Habitat of Caledoniscincus pelletieri sp. nov. on Dôme de Tiébaghi—closed forest remnant bisected by old mining track (A) on southwest rim of plateau, and closed-canopy forest to c. 15 m with dense understorey of palms (B) where paratype AMS R. 174994 was collected.