Oligosoma kokowai, Melzer & Bell & Patterson, 2017

Melzer, Sabine, Bell, Trent & Patterson, Geoff B., 2017, Hidden conservation vulnerability within a cryptic species complex: taxonomic revision of the spotted skink (Oligosoma lineoocellatum; Reptilia: Scincidae) from New Zealand, Zootaxa 4300 (3), pp. 355-379 : 361-365

Oligosoma kokowai sp. nov.

Figure 3a , b

Holotype. Brothers Island (41° 07’S, 174° 26’E), NMNZ RE000305, female (coll. R. Dell, 11 Sep 1948)

Paratypes (19 specimens). Brothers Island (41° 07’S, 174° 26’E), 3 specimens ( NMNZ RE000307, female; NMNZ RE000308, immature; NMNZ RE000309, male) (coll. C. Lindsay, 11 Sep 1948) ; Stephens Island (40° 40’S, 174° 00’E), NMNZ RE000313, unknown (coll. C. Lindsay, 13 Sep 1948) ; Stephens Island - No 3 house (40’S, 174° 00’E), NMNZ RE005217, female (coll. M. Thompson, 0 6 Nov 1998) ; St Arnaud (41° 46’S, 172° 44’E), NMNZ RE003999 (S357), male (coll. B. Thomas, 20 Jul 1968) ; Aniseed valley , Roding River (41° 23’S, 173° 15’E), NMNZ RE006227, immature (coll. G. Patterson, 0 9 May 1984) ; St Arnaud (41° 46’S, 172° 44’E), 2 specimens ( NMNZ RE004148 (S506), female; NMNZ RE004149 (S507), male) (coll. B. Thomas, 22 Oct 1969) ; Somes Island (41° 15’S, 174° 53’E), NMNZ RE000909, female (coll. D. Fairfax, 20 Jan 1958) ; Somes Island (41° 15’S, 174° 53’E), 2 specimens ( NMNZ RE005262, female; NMNZ RE005263, male) (coll. K. Neil, Jan 1997) ; Martinborough (41° 13’S, 175° 27’E), NMNZ RE001009, female (coll. Hewett, Aug 1963) ; Napier (39° 29’S, 176° 55’E), 2 specimens ( NMNZ RE003648 (S3), female; NMNZ RE003819 (S177), female) (coll. A. Whitaker, 17 Apr 1966) ; Cape Turakirae (41° 26’S, 174° 55’E), NMNZ RE004122 (S480), male (coll. A. Whitaker, 0 7 Aug 1969) ; Ward Island (41° 18’S, 174° 52’E), NMNZ RE005458, female (coll. R. Ainsworth, 0 7 Jan 1984) ; Turakirae Head , Lower Hutt (41° 26’S, 174° 55’E), NMNZ RE006226, male (coll. S. Keall, 12 Jan 1984) ; Napier (39° 32’S, 176° 55’E), NMNZ RE005320, female (coll. K. Hewitt, 12 Dec 2006) .

Diagnosis. Although Greaves et al. (2007) distinguished two subclades within this clade based on genetic variation, we could not find any significant morphological differences to warrant splitting them into two species. This species, O. kokowai , can be distinguished from other species in the O. lineoocellatum species complex by a combination of characters. The subdigital lamellae count is usually below 24, compared with O. prasinum and O. elium where it is usually above 24. All the specimens examined had one nuchal pair, in contrast with O. prasinum and O. lineoocellatum which always have more than 1 pair, and O. elium which usually has more than 1 pair. There are significant differences between O. kokowai and O. elium (lower ciliary count, AG/SF), O. lineoocellatum (lower ciliary count, SVL/HW), and O. prasinum (midbody scale count) ( Figure 6b ). Dorsal ocelli continue down tail unlike in many specimens of O. prasinum and O. elium . Pale dorsolateral stripes are usually much more pronounced than in O. prasinum . The ventral surface is often bright red-orange, unlike any of the other three species.

Description of Holotype. Habit lacertiform, body elongate, oval in cross-section; limbs well developed, pentadactyl. Lower eyelid with a transparent palpebral disc, bordered on sides and below by small, oblong granules. Snout moderately blunt. Nostril centred in lower middle of nasal, not touching bottom edge of nasal, pointing up and back. Supranasals absent. Rostral narrower than deep. Frontonasal broader than long, not separated from frontal by prefrontals meeting in midline. Frontal longer than broad, shorter than frontoparietal and interparietal together, in contact with 2 anteriormost supraoculars. Supraoculars 4, 2nd largest. Preoculars, 2, upper one the larger. Frontoparietals distinct, larger than the interparietal. A pair of parietals meeting behind interparietal and bordered posteriorly by a pair of nuchals and temporals, also in contact with interparietal, frontoparietal, 4th supraocular, and 2 postoculars. Loreals 2, anterior one the larger; 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 7, 6th largest. Infralabials 6, 5th largest. Fifth supralabial below centre of the eye. Temporals: 1 primary; 2 secondary. Ear opening round, moderately large, lacking projecting granules on anterior margin. Suboculars 5, 2nd and 3rd separated by 5th supralabial. Mental broader but shallower than rostral. Postmental larger than mental. Chinshields 3 pairs. Dorsal scales similar in size to ventral scales, weakly striate. Ventral scales and subdigital lamellae smooth. Adpressed limbs not meeting. Digits moderately long, subcylindrical. Third front digit similar in length to 4th.

Measurements (in mm; holotype with the variation shown in the specimens examined in parentheses). SVL 81.1 (mean 73.1, range 35.4–90.3), HL 11.5 (mean 11.5, range 6.9–13.3), HW 6.7 (mean 6.4, range 3.6–7.8), AG 44.8 (mean 40.1, range 16.1–50.2), SF 29.0 (mean 27.1, range 15.0–32.1), S-Ear 14.1 (mean 13.9, range 7.8– 16.8), EF 15.0 (mean 14.1, range 7.8–17.3), HLL 24.1 (mean 23.7, range 12.0–28.0).

Variation (holotype with the variation shown in the paratypes in parentheses).

Upper ciliaries 7 (mean 6, range 5–8); lower ciliaries 9 (mean 8, range 5–10); nuchals 1 pair (mean 1 pair, range 1–1 pair); midbody scale rows 34 (mean 34, range 32–37); ventral scale rows 94 (mean 84, range 74–97); subdigital lamellae 24 (mean 23, range 21–24); supraciliaries 5 (mean 5, range 4–5); suboculars 5 (mean 5, range 4–5). Frontonasal seldom separated from frontal by prefrontals meeting in midline. Anterior loreal usually in contact with first and second supralabial, posterior loreal always in contact with second and third supralabial. Supralabials 7 (usual) or 8, the sixth or seventh the largest. Infralabials 6 (usual) or 7. Projecting scales usually present in ear opening. Maximum SVL 90.3 mm.

Only 4 of the specimens examined had an intact tail, tail length of intact specimens ranging between 66–95 mm. Mean TL/SVL = 1.11. Ratios for morphological measurements (± SD): AG/SF 1.47 ± 0.16; S-Ear/EF 0.99 ± 0.08; HL/HW 1.81 ± 0.09 (N=20).

Colouration. This is variable among specimens, but the most common colouration is as follows: No middorsal stripe. Dorsal surface olive green, with regular light and dark flecking, 6 scale rows wide, grading into pale dorsolateral stripe extending from behind eye to base of tail, becoming indistinct thereafter. This pale stripe extends into dark brown lateral stripe three or four scale rows wide, running from behind nostril through eye to base of tail, becoming indistinct thereafter. This brown band is speckled with light and dark along its length and bordered below by another pale band that breaks up into irregular cream and dark brown mottling. Grading into a grey or red-orange unmarked belly. Soles of feet grey. Throat usually unmarked. Outer surface of forelimbs olive green, speckled with light and dark. Colouration can be variable, O. kokowai in Nelson can be everything from pale, almost straw-brown to mid-dark brown to olive to bright or even dark green dorsally (T. Jewell, pers. comm.). They do not appear to be sexually dichromatic. Juveniles have a brown base colour and lack the characteristic green shading of adults.

Etymology. McCann (1955) gave the specific name “ festivum ” to the holotype. However, this name is no longer valid. Another skink species from New Caledonia was also described in Leiolopisma by Jean Roux (1913). Roux's taxon was described as Lygosoma (Liolepisma) austro-caledonicum festivum , while McCann's was described as Leiolepisma festivum . Because they were first both described in the same genus/subgenus ( Liolepisma being a misspelling of Leiolepisma , and subgenera being treated as equivalent to genera by the Code of Zoological Nomenclature), they are primary homonyms, and the junior homonym is permanently unavailable [Glenn Shea, pers. comm.] This also applies to Wells & Wellington’s (1985) resurrection of McCann’s species name. The specific name is from the Maori kōkōwai , meaning red or auburn and refers to the colour of the ventral surface of this skink. The current accepted vernacular name is ‘spotted skink’ ( Bell 2014) but we propose changing it to ‘northern spotted skink’ to distinguish it from the other species in this complex.

Figures

FIGURE 3. a) O. kokowai holotype, RE 000305, Brothers Island (photo: Jean-Claude Stahl). b) Live specimen of O. kokowai, Matiu / Somes Island.

FIGURE 6. a – e. Notched boxplots comparing the morphological characteristics of the species in the Oligosoma lineoocellatum species group (O. elium, O. kokowai, O. lineoocellatum, O. prasinum). a) snout-vent length (SVL) / head width (HW), b) midbody scales, c) lower ciliaries, d) axilla-groin (AG) / snout-forelimb (SF), e) upper ciliaries. If there is no overlap between two medians, then the medians are significantly different at a 95 % confidence interval.