Caledoniscincus constellatus, Sadlier, Ross A., Whitaker, Tony, Wood, Perry L. & Bauer, Aaron M., 2012
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publication ID |
https://doi.org/ 10.5281/zenodo.209940 |
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DOI |
https://doi.org/10.5281/zenodo.5661833 |
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persistent identifier |
https://treatment.plazi.org/id/C11687D6-FFED-FFE0-BC9D-6450C9462DDC |
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treatment provided by |
Plazi |
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scientific name |
Caledoniscincus constellatus |
| status |
sp. nov. |
Caledoniscincus constellatus sp. nov.
Figs. 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5
Holotype. MNHN 2011.0228 (formerly AMS R171497) Pointe de Vavouto, Province Nord, New Caledonia 21°00'39.8"S 164°41'04.3"E (collected R.A. Sadlier and A.H. Whitaker 27 Jan. 2009).
Paratypes. AMS R171496 Pointe de Vavouto 21°00'35.1"S 164°41'02.0"E (collected R.A. Sadlier and A.H. Whitaker 27 Jan. 2009); AMS R171470 Pointe de Vavouto 21°00'40.3"S 164°41'07.9"E (collected R.A. Sadlier and A.H. Whitaker 26 Jan. 2009); AMS R171471 Pointe de Vavouto 21°00'34.5"S 164°41'02.0"E (collected R.A. Sadlier and A.H. Whitaker 26 Jan. 2009).
Additional material examined. QM J.58022 Massif d’Ouazangou 20°44’34”S 164°28’03"E collected R. Raven 14 May 1992.
Etymology. The species epithet is Latin for studded with stars and refers to the pattern of white specks on the dorsal surface of males of the species.
Diagnosis. Caledoniscincus constellatus sp. nov. can be distinguished from the other species of Caledoniscincus by the following combination of characters: (a) moderately small size (adult male 46–57mm SVL; adult female 57mm SVL); (b) tail long, approximately 2.0+ longer than body; (c) the fourth toe being covered with 17–19 scales above and 31–33 lamellae below; (d) a broad pale midlateral stripe; (e) bright yellow ventral colour in adults of both sexes.
The presence of a pale midlateral stripe in Caledoniscincus constellatus sp. nov. will distinguish it from all other species of Caledoniscincus except C. haplorhinus and populations of C. austrocaledonicus from the central and northern regions of New Caledonia, both of which also have this character state, and which also occur in the northwest region of New Caledonia. Caledoniscincus constellatus sp. nov. is sympatric with C. haplorhinus on the Pointe de Vavouto, and locally sympatric with both C. haplorhinus and C. austrocaledonicus which occur on the Massif d’Ouazangou-Taom. The general pattern of C. constellatus sp. nov. and C. haplorhinus are similar to each other in that the males and females are two-toned with a light dorsal surface contrasting with a noticeably darker upper lateral surface which is bordered below by a pale midlateral stripe. The most consistent difference between the two species, and with C. austrocaledonicus , is in the positioning of the pale midlateral stripe where it contacts the back of the ear opening ( Fig. 2 View FIGURE 2 ): in C. constellatus sp. nov. the pale midlateral stripe is broad, meets most of the posterior edge of the ear and then continues broadly from the anterior edge of the ear unbroken to the anterior-most upper labials; in C. haplorhinus the pale midlateral stripe is narrow, joins the upper posterior edge of the ear and forms a pale edge over the ear and continues anteriorly as a row of broken pale markings to the anterior upper labials; in C. austrocaledonicus the pale midlateral stripe is narrow, follows a line anteriorly towards the middle of the rear edge of the ear opening, but loses definition approaching the ear opening. The tail of C. constellatus sp. nov. (208% SVL) is also longer than that of C. haplorhinus (maximum 173% SVL) or C. austrocaledonicus (~150% SVL).
There are also marked differences in ventral colouration between these three species. Adult male and female C. constellatus sp. nov. have bold yellow ventral surfaces which distinguish them from C. haplorhinus (adult males moderate yellow; adult females pale yellow) and from C. austrocaledonicus (adult males orange; adult females moderate yellow). Further, the reticulate pattern of narrow, bicoloured transverse bars in adult male C. constellatus sp. nov. is unique and readily distinguishes them from adult male C. haplorhinus which lack any transverse markings on the dorsal surface, and male C. austrocaledonicus which has a pale vertebral marking (rough stripe or variably connected blotches) down the centre of the back.
In scalation there is highly significant levels of difference (t <0.005) between C. constellatus sp. nov. and C. haplorhinus (all populations included) in toe scalation and number of midbody scale rows ( Table 1 View TABLE 1 ). However, there is overlap in range of values for these characters and they are not significantly different when compared with syntopic C. haplorhinus , limiting their usefulness diagnostic markers in the identification of individuals.
Description. Based on three adult males (46–52mm SVL), one adult female (57mm SVL) from Pointe de Vavouto. Measurements: adult size 46–57mm SVL; distance from axilla to groin 58.6–63.2% SVL x = 61); distance from forelimb to snout 30.7–35.4% SVL (x = 33.9); hindlimb length 43.9–47.5% SVL (x = 45.3); tail length of individual with most complete tail 208.1% SVL.
Scalation: midbody scale rows 28–30 (x = 28.5, sd = 1.00); dorsal scale rows 61–65 (x = 63.0, sd = 1.63); scales on top of fourth finger 10–12 (x = 11, sd = 0.81); lamellae beneath fourth finger 16–18 (x = 16.5, sd = 0.7); scales on top of fourth toe 17–19 (x = 18.0, sd = 0.82); lamellae beneath fourth toe 31–33 (x = 31.9, sd = 0.85).
Osteology: presacral vertebrae 28 (n = 1) – 29 (n = 3); postsacral vertebrae 43 (n = 1) for individual with longest tail, tip (19%) reproduced.
Colour and pattern in life ( Fig. 3 View FIGURE 3 ): Dorsal surface of males predominately light brown (larger individuals) to grey-brown (smallest individual) with a reticulate pattern of narrow (one scale width), bicoloured transverse bars, the individual scales of which are black with one to several small white spots medially within the scale and/or along its anterior edge, and the scales making up the of lighter interspaces between the dark transverse bars are densely peppered with minute black spots. Top of head bearing a mix of grey and light brown (larger individuals) or more uniformly grey-brown (smallest individual). Lateral surface of body and head black with a bold white midlateral stripe that extends along the side of the head from the anterior labials to the anterior edge of the ear, and then along the neck from the lower and posterior edge of the ear opening and passing above the forelimb and along the body as a continuous stripe (one scale width) to the edge of the hindlimb, continuing along the hindlimb as a lighter and narrower grey stripe bordered below by a continuation of the black lower lateral colour. The light dorsal and dark lateral surfaces are well differentiated and highly contrasting, the dorsolateral edge is irregular and defined by a pale narrow stripe that is cream with brown suffusion between the naris and eye, white between the eye and level of the forelimb, and of variable in width and clarity of colour along the remainder of the body being narrow (half scale width) and variably suffused with brown to wide (one scale width) and white in colour, with the wider and paler areas appearing more as a series of white blotches. Tail grey-brown above with some continuation medially of the light brown dorsal colouration of the body. Lateral surface of the tail dark basally but mid-brown over the remainder of its length and bordered above by a very narrow, unbroken, black edge along the dorsolateral margin. Undersurface of body and neck white and strongly contrasting with the dark lower lateral surface, the body with a bold yellow flush anteriorly to the level of the forelimbs. Lower labials each with large dark markings, scales along inner edge of jaw line also with scattered dark markings, and the mental scale with dark blotches and numerous minute dark specks to give an overall blackish appearance.
Adult female with the dorsal surface grey-brown above with a series of small, widely separated dark blotches along the vertebral line of the neck, body and base of tail, continuing as a narrow dark vertebral streak along the remainder of the tail. Lateral surface as for males but with the pale dorsolateral markings usually white, near continuous and narrow (1/2 scale width).
Details of Holotype: Adult male (MNHN 2011.0228); size 49.5 mm SVL; tail length 103 mm (19.5 mm of tip reproduced). Midbody scale rows 28; dorsal scale rows 61; dorsal scales of fourth finger 11/11; lamellae of fourth finger 16/16; dorsal scales of fourth toe -/18; lamellae of fourth toe -/31.
Comments. The single juvenile specimen in the Queensland Museum from the Ouazangou massif is assigned to C. constellatus sp. nov. on the basis of having the black upper and lower lateral colouration (including the side of the head) and distinctive broad, pale midlateral stripe and the contact of this stripe with the ear opening diagnostic of the population at the type locality. However, this specimen is poorly preserved and the scalation characters are difficult to assess thus not allowing comparison with the type series from Vavouto with any confidence, although it does appear to have a shorter tail (166% versus 208% SVL) indicating the possibility of some regional differentiation, the significance of which can only be assessed with more samples.
Distribution and biology. Caledoniscincus constellatus sp. nov. occurs in the northwest coast of the Grande Terre on Pointe de Vavouto and on the Massif d’Ouazangou. The site at Vavouto is mostly covered by disturbed vegetation but there is a mixture of dense to open maquis and Acacia shrubland on the coastal hills and remnant sclerophyll forest (‘Formation Jaffré’) in the gully. This site is unique for the occurrence of sclerophyll forest on serpentine. The new species was found in both habitats, and was syntopic with Caledoniscincus haplorhinus which was more abundant. Sclerophyll forest habitat is extremely restricted in distribution, but the mosaic of maquis and acacia shrubland is widespread and extends to the adjacent coastal hills and low-elevation slopes and valleys at the base of the Massif de Koniambo. Investigation of maquis and acacia shrubland at the base of Massif de Koniambo did not record C. constellatus sp. nov., but did record C. haplorhinus . The single juvenile from Massif d’Ouazangou was collected in an insect pitfall trap set in Acacia shrubland in a west-facing gully around 400 m elevation.
Conservation status. Potential threats to the species preferred habitats includes an array of low- to moderatelevel human-mediated impacts, including: extensive loss and fragmentation of sclerophyll forest, near coastal maquis and Acacia shrubland on the central-west and north-west coast from clearing for ranching and agriculture; a decline in the extent and quality of remaining sclerophyll forest, maquis and Acacia shrubland in the long-term from repeated wildfires and, where they occur on ultramafic massifs, from activities associated with nickel mining; a potentially very high risk of a decline in quality (and consequently in extent) of the remaining sclerophyll forest fragments at Pointe de Vavaouto from the immediate proximity of the infrastructural development associated with the Koniambo mine processing facility; a potentially severe negative impact from the invasive little red fire ant ( Wasmannia auropunctata ) in sclerophyll as indicated by studies on congeners (Jourdan et al., 2001).
Based on the threats identified above, the species extremely restricted range and its occurrence at only two locations, C. constellatus sp. nov. is ranked as Critically Endangered on IUCN Red List criteria (IUCN 2001).
Comparative material examined. The following specimens of Caledoniscincus haplorhinus were used in the morphological comparisons: AMS R77407, R77409, R77427, R77429, R77437, R77449–52, R78319–20, R78322, R78326-28 Nouméa, Fambourg Blanchot 22°18'S 166°27'E; AMS R135119-23 Nouville, Isle Nou 22°16'S 166°24'E; R146433–4, CAS 198763–71 Plage de Ouano 21°50'43"S 165°48'33"E; AMS R144257–58, R144284–89 Grottes de Koumac, 9km E of Koumac 20°33'18"S 164°21'49"E; AMS R146459–70, R146472 Pindaï, Plage de Pindaï 21°21'26"S 164°57'11"E; AMS R171478–81 Pointe de Vavouto 21°00'40.3"S 164°41'07.9"E; AMS R171483 Pointe de Vavouto 21°00’36.4”S 164°41’8.6”E; AMS R171491 Pointe de Vavouto 21°00’ 17.8S 164°46’ 7.5E.
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