Nannoscincus garrulus, Sadlier & Bauer & Smith, 2006

Sadlier, Ross A., Bauer, Aaron M. & Smith, Sarah A., 2006, A New Species of Nannoscincus Günther (Squamata: Scincidae) from High Elevation Forest in Southern New Caledonia, Records of the Australian Museum 58 (1), pp. 29-36 : 31-36

Nannoscincus garrulus n.sp.

Figs 1–5

Type material. HOLOTYPE: MNHN 2003.1002 Pic Ningua , 17.0 km south of Nakaré, Province Sud, New Caledonia (21°44'25"S 166°09'21"E), collected by R. A. Sadlier, A.M. Bauer, T. Jackman, & C.C. Austin on 27 September 2002 . PARATYPES: AMS R163451–52 , CAS 226164–65 , MCZ R183655 same collection data as holotype; AMS R163453– 57 , CAS 226166–67 Pic Ningua , 17.0 km south of Nakaré, Province Sud, New Caledonia (21°44'36"S 166°09'02"E), collected by R. A. Sadlier, A.M. Bauer, T. Jackman, & C.C. Austin on 26 September 2002 .

Additional material. The following specimens referable to N. garrulus were collected in wet pit traps on both Pic Ningua and Mont Çidoa in 1993–1995, but do not form part of the type series: AMS R151490–97 , R151499–511 , R151513–17 , R151520–26 , R151528–34 , R151536–46 , AIM 1702 , 1704 , 1733 , 1735–39 , 1775–78 , 1783–98 , 1800 – 02,1815 –18, 1820–21 from a range of sites (n = 7) between 970–1110 m elevation on Pic Ningua; AIM 1703 , 1705 , 1734 , 1799 , 1814 , 1819 Mont Çidoa (21°44'S 166°13'E) .

Diagnosis. Nannoscincus garrulus is a large and elongate member of the genus with a two-toned colour pattern on the body ( Fig. 1 ). It can be distinguished from all other members of the genus by the following combination of characters: frontoparietals divided; two loreals, anterior loreal a small semilunar scale positioned off the posterodorsal edge of the enlarged nasal scale and failing to contact the labials; seven or more upper labial scales; left and right oviduct present in females; lower eyelid “scaled”; ear opening minute; body scales striated; adult dorsal colour two-toned; ear opening positioned four scales posterior to lower secondary temporal; presacral vertebrae 33–34; phalangeal formula for manus 2.3.3.3.3; phalangeal formula for pes 2.3.4.4.3.

The first four characters will distinguish N. garrulus from N. rankini , N. greeri , N. hanchisteus , N. humectus , N. exos , and N. manaueti , all of which have fused frontoparietals, a

n.sp. (MNHN 2003.1002) showing scalation.

single loreal, a windowed lower eyelid, and the oviduct present on the right side only. It can be further distinguished from these species by having fewer phalanges on the third and fourth fingers of the manus.

Nannoscincus mariei is somewhat intermediate between the two morphologically-defined species groups, in possessing the derived character state of a single loreal and loss of the left oviduct, but retaining the primitive character state of divided frontoparietals. It also has a “scaled” lower eyelid similar to N. gracilis , N. slevini , and N. garrulus , the structure and possible polarity of which has been discussed elsewhere ( Sadlier, 1990). Nannoscincus garrulus is readily distinguished from N. mariei by the presence of two (vs one) loreal scales, and the presence of a small but obvious ear opening (vs ear opening absent).

Nannoscincus garrulus most resembles N. gracilis and N. slevini . It is noticeably larger (maximum SVL 52.5 mm) than either N. gracilis (SVL 49.0 mm) or N. slevini (SVL 43.0 mm), and has seven or more upper labial scales whereas both N. gracilis and N. slevini have six. It can be further distinguished from N. slevini by the presence of five (vs four) digits on the manus, and from N. gracilis in having more phalanges on the fifth digit of the manus (2.3.3.3.3 vs 2.3.3.3.2).

Etymology. The specific epithet is the Latin word garrulus , meaning talkative, and is in reference to the tendency for this species to emit a squeaking sound when distressed ( Bauer et al., 2004).

Description. Based on the holotype and 12 paratype specimens comprising six adult males, three adult females, and four subadults—measurements are for adult specimens only. Mean values of certain characteristics are reported

with standard deviations. Measurements: SVL 45.0– 52.5 mm; distance from axilla to groin 64.4–66.7% of SVL (¯x = 65.4); distance from forelimb to snout 28.6–31.3% of SVL (¯x = 29.9); hindlimb length 19.0–22.2% of SVL (¯x = 20.6); tail length 106.1% of SVL (estimated from individual with most complete tail). Scalation: Head ( Fig. 2 ): nasals moderately separated, very large and extending laterally along the side of the head; frontonasal broader than long; prefrontals very small and widely separated; supraciliaries 7 (81%), rarely 8, with the first supraciliary contacting frontal (thereby excluding contact between the prefrontal and first supraocular); frontal short, almost as broad as long; supraoculars four; frontoparietals paired; interparietal distinct; parietals each usually bordered by a single nuchal and upper secondary temporal scale (73%) but showing some fragmentation of scales in this region such that nuchals (19%) or upper secondary temporals (8%) are sometimes divided to form two scales; upper labials 7 (96%), rarely 8; lower labials 7; two loreals, anterior loreal reduced to a small semilunar scale positioned off posterodorsal edge of enlarged nasal scale, posterior loreal also semilunar in shape, either contacting the labials narrowly (42%) or excluded from contact by extension of posterior edge of large nasal back to contact lower preocular; single large anterior subocular; pretemporals two; postoculars 3 (77%) or 4; primary temporal single (46%), or divided to form two similar sized scales; upper secondary temporals usually single (92.7%), occasionally divided to form two scales; lower secondary temporals single; tertiary temporals two; postlabials two; ear opening positioned four scales posterior to lower secondary temporal; postmental contacting first and second lower labial; chinshields three, first pair in broad contact. Body: scales striated, midbody scale rows 22–24 (¯x = 22.8±1.01); paravertebral scales 60–73 (¯x = 66.7±3.5). Limbs: scales on top of fourth finger 4–5 (¯x = 4.05±0.14); lamellae beneath fourth finger 4–5 (¯x = 4.1±0.30), rudimentary interdigital webbing at base of fingers ( Fig. 3 ); scales on top of fourth toe 6–7 (¯x = 6.05±0.14), the basal scale present as a large scale at base of third and fourth toes; lamellae beneath fourth toe 13–16 (¯x = 13.77± = 0.83). Osteology: presacral vertebrae 33 or 34 (54%, n = 13); postsacral vertebrae 37–38 (n = 2) phalangeal formula for manus and pes 2.3.3.3.3 and 2.3.4.4.3 (n = 13), respectively.

Colouration (in preservative): dorsal colour light to mid brown, with scattered dark flecks aligned along vertebral axis to form a broken longitudinal line; nape with a variably defined pale blotch with a dark posterior edge. Lateral surface noticeably darker than dorsal, unmarked. Dorsal and lateral surfaces defined by a dark brown to black (darker than lateral colour) dorsolateral stripe, pale-edged above. Dark dorsolateral stripe extends from back of eye (inflected over tympanic region) to level of hindlimbs, breaking up and becoming poorly defined along tail. Head slightly darker at sides than adjacent areas of body, dark colouring extending around lower edge of rostral scale and inflecting upwards to form a dark midrostral streak in boldly marked individuals, subocular labials with pale markings. Ventral surface pale with a light to heavy concentration of scattered brown markings at edges and regular brown markings to throat region.

Distribution and habitat. At present known only from Pic Ningua and Mont Çidoa, at the northern edge of the extensive ultramafic block that covers much of the southern third of New Caledonia ( Fig. 4 ). Closed forest habitat ( Fig. 5 ) is restricted to the top of these mountains from about 900 m elevation. All specimens were collected under logs and rocks in the vicinity of a small, shallow gully. The forest floor was generally dry at the time of collection, the island not having had significant rainfall since the previous wet season (January–March). The apparent absence of individuals away from the gully could indicate the species concentrates in areas where soil moisture is present, such as the gullies, during periods of seasonal dryness. Like all members of the genus, N. garrulus is highly desiccationprone (Bauer & Sadlier, 2000).

The nearest records of the allied Nannoscincus gracilis are from mid elevation forest at Col de Nassirah (348 m) 10 km to the south and west, and Col de Petchécara (435 m) 15 km to the north and east, whereas N. slevini has been recorded from Mt Canala and Plateau de Dogny 25 km to the north and east.

Natural history. All specimens made faint but distinctive squeaks when handled, presumably as a defensive measure ( Bauer et al., 2004). This is the only Nannoscincus , and only New Caledonian scincid, for which vocalization has been documented (under the name N. cf. gracilis — Bauer et al., 2004). One adult female collected in January, the summer wet season, contained two large yolked oviducal eggs (one in the left oviduct and one in the right), and another specimen two large yolked ovarian follicles.

Conservation status. Nannoscincus garrulus has an extremely restricted distribution, being known only from the type locality at Pic Ningua and adjacent Mont Çidoa. That it was not recorded from high elevation on forest on nearby Mt Do indicates the species is not necessarily likely to be more widely distributed. Closed forest habitat occurs at Bwa Bwi (19 km ESE of Pic Ningua and 9 km SSE of Mont Çidoa) and possibly Dent de St-Vincent (20 km SSE of Pic Ningua), both of which lie along a more or less continuous high elevation ridge. However, neither site has yet been surveyed. The size of high elevation forest patches in this area of the southern ultramafic block is extremely small, especially on Pic Ningua and Mont Çidoa.

The forest on Pic Ningua has been set aside as a special reserve. An access road to the mining operation passes along one edge of the forest. Given the very steep relief of the terrain and the small size of the forest patches, any mining activity through or adjacent to the forest has the potential to alter a significant proportion of the overall area of the forest. The mid slopes of the ranges in this part of the island are covered with maquis, and there is a very narrow transition zone between this and the high elevation closed forest. Frequent burning of maquis shrubland, particularly in areas near settlement or development, and its impact upon the forest edge is considered a significant threat to the overall size and quality of isolated closed forest patches in New Caledonia ( Fig. 5 ).

Given the species’ highly restricted distribution, the relatively small size of the remaining moist forest on Pic Ningua and Mont Çidoa, and the threat to this habitat from fire, the species would be ranked as Endangered under a modified IUCN classification system (Sadlier & Bauer, 2003) where area of occupancy <100 km 2, number of populations = 2, and there is an apparent continuing decline in area, extent and/or quality of habitat.

Relationships. A previous scheme of relationships for Nannoscincus ( Sadlier, 1990) identified two groups, the N. gracilis group comprising N. gracilis + N. slevini , and the N. mariei group comprising the species N. mariei + N. rankini + N. greeri . The species N. hanchisteus , N. humectus , and N. exos were subsequently added to the latter group ( Sadlier et al., 2002), and later N. manaueti ( Sadlier et al., 2004) .

The N. mariei group is a well diagnosed clade, characterized by loss of the left oviduct in females, loss of the anterior loreal scale, and a reduced number of lower labial scales. The N. gracilis group also constitutes a clade characterized by a reduction in the number of phalanges in the third and fourth digits of the manus, a pattern of scale reduction in the loreal region resulting in both the anterior and posterior loreals being reduced to small semilunar scales, and a tendency towards greater elongation of the body as seen in the greatly increased number of presacral vertebrae.

Nannoscincus garrulus is clearly a member of the N. gracilis group. It is also very distinct from either N. gracilis or N. slevini in having a number of unusual scalation characteristics including: fragmentation in the region of the primary temporal such that two scales rather than one are often present; fragmentation in the region of the nuchal such that two or more scales rather than one are sometimes present; an increased number of post temporal scales such that four, rather than three or fewer, scales occur between the lower secondary temporal and the ear opening; a tendency for displacement of the posterior loreal by contact between the lower preocular and nasal to exclude contact between the posterior loreal and upper labial scales on occasions; an increased number of lower labial scales such that seven scales border the lip between the mental scale and angle of the jaw; and the presence of seven upper labial scales with three rather than two labial scales positioned below the eye in the area between the anterior preocular scale and postsubocular scales (the fourth wholly bordering the lower eyelid, the third and fifth partially). It is likely that the condition seen in N. garrulus for the first three of these characters is apomorphic. The polarity of the upper labial scale character in N. garrulus is, however, less clear. All other species of Nannoscincus tend to have only two scales (more or less similar in size) positioned immediately below and wholly or partially bordering the lower eyelid. It is possible the extra upper labial bordering the lower eyelid of N. garrulus is derived from a division of one of the two upper labial scales usually seen in other species of Nannoscincus that are positioned immediately below and bordering the lower eyelid.

ACKNOWLEDGMENTS. The authors thank the New Caledonian authorities for permission to collect and conduct research in Province Sud, particularly M. Richard Farman. The types of Nannoscincus garrulus were collected during field research funded by grant DEB 0108108 from the National Science Foundation (U.S.A.), and the specimens were collected under permit 6034–2075/DRN issued by the Direction des Ressources Naturelles of the Province Sud, New Caledonia and exported under permit 6034–2330/DRN of the same authority. The authorities at Société le Nickel (SLN) kindly allowed access to Pic Ningua. Unfailing logistical support and encouragement was provided by Jean Chazeau of the IRD Centre de Nouméa. Hannah Finlay produced the illustration of the head shields ( Fig. 2 ). Todd Jackman and Christopher Austin assisted with fieldwork.

Figures

Fig. 1. Paratype of Nannoscincus garrulus n.sp. (AMS R163457).

Fig. 2. Dorsal (upper), lateral (middle), and ventral (lower) views of the head of holotype of Nannoscincus garrulus

Fig. 3. Left manus of holotype of Nannoscincus garrulus n.sp. (MNHN 2003.1002) showing extensive underside “webbing” between digits of the forelimbs (right) and enlarged dorsal scales at the base of the third and fourth digits (left).

Fig. 4. Map of New Caledonia showing location of Pic Ningua and adjacent Mont Çidoa,

Fig. 5. Isolated closed forest patch on Mont Çidoa, typical of habitat in the area from which the types of Nannoscincus garrulus n.sp. were collected.