Oligosoma auroraensis, Melzer & Hitchmough & Bell & Chapple & Patterson, 2019
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publication ID |
https://doi.org/ 10.11646/zootaxa.4623.3.2 |
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publication LSID |
lsid:zoobank.org:pub:402E9C29-3A36-4A0A-AE8D-5D7B0C335701 |
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persistent identifier |
https://treatment.plazi.org/id/0390B574-CB3F-2B0E-FF2E-E08EFCB4F8C7 |
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treatment provided by |
Plazi |
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scientific name |
Oligosoma auroraensis |
| status |
sp. nov. |
Oligosoma auroraensis sp. nov.
Figures 10a, b View FIGURE 10
Synonyms
HARDY 1977
BIDINOSTI et al. 2008; GREAVES et al. 2008; CHAPPLE et al. 2009; JEWELL & MORRIS 2011; TOWNS et al. 2002; DENT 2016
Oligosoma aff. infrapunctatum “southern North Island”
HITCHMOUGH, R., BULL, L. & CROMARTY, P. 2007; HITCHMOUGH et al. 2010; HITCHMOUGH et al. 2013; BELL 2014; HITCHMOUGH et al. 2016a; HITCHMOUGH et al. 2016b
Oligosoma “ southern North Island”
WILES et al. 2017
Oligosoma aff. infrapunctatum “ Hawke’s Bay ”
VAN WINKEL et al. 2018.
Holotype. Ocean Beach, Cape Kidnappers (39º 45’S, 177º 00’E), NMNZ RE007397, male (coll. T. Bell 26 Mar 2015). GoogleMaps
Paratypes (4 specimens). Ocean Beach, Cape Kidnappers (39º 45’S, 177º 00’E), 4 specimens: NMNZ RE007400, female ; NMNZ RE007398, female ; NMNZ RE007399, female ; NMNZ RE007396, female (coll. T. Bell 26 Mar 2015) .
Other specimens examined (1 specimen). Waimarama, Hawke‘s Bay (39º 49’S, 176º 59’E), NMNZ RE000959, female (coll. Wilson, unknown date).
Diagnosis. O. auroraensis can be distinguished from other species in the O. infrapunctatum species complex by a combination of characters ( Figure 4 View FIGURE 4 a–j). Compared with O. newmani which has 20 or fewer subdigital lamellae on fourth hind toe O. auroraensis usually has more than 20. The mean TL/SVL in O. auroraensis is 1.38 compared with 1.22 for O. newmani and there is also a significantly higher VS count in O. auroraensis compared with O. newmani . There are statistical differences between O. albornense and O. auroraensis (VS). O. albornense differs from O. auroraensis in having subdigital lamellae usually 21 or above ( O. auroraensis ) versus 21 or below. O. albornense appears to have a shorter tail (1.28 TL/SVL versus mean TL/SVL of 1.38 in O. auroraensis ). VS count in O. robinsoni is usually less than 75 whereas in O. auroraensis it is greater than 75. It differs from O. robinsoni i n having subdigital lamellae usually 21 or above ( O. auroraensis ) versus usually 21 or below. The mid-dorsal stripe is to base of tail in O. robinsoni , past base of tail in O. auroraensis . There are statistical differences between O. salmo and O. auroraensis (VS). O. salmo usually has fewer than 20 subdigital lamellae on the fourth hind toe versus usually greater than 20. It differs from O. auroraensis in having subdigital lamellae usually 21 or above ( O. auroraensis ) versus usually 21 or below. It appears to have a shorter tail (1.25 TL/SVL versus mean TL/SVL of 1.38 in O. auroraensis ). None of the O. auroraensis specimens have the extra scale between prefrontals possessed by O. infrapunctatum and O. auroraensis has 7 infralabials whereas O. infrapunctatum has 8.
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 similar in depth to width. 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, 2 nd largest. Preoculars, 2, upper upper one 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, 3 rd supraocular, and 2 postoculars. Loreals 2, similar size; anterior loreal in contact with 1 st and 2 nd supralabial, posterior loreal, prefrontal, frontonasal, and nasal; posterior loreal in contact with 2 nd and 3 rd supralabial, 1 st subocular, upper and lower preocular, prefrontal, and anterior loreal. Supralabials 7, 7 th largest. Infralabials 6, several equally largest. Fifth supralabial below centre of the eye. Temporals: 1 primary; 2 secondary. Ear opening round, moderately large (1.9% as percentage of SVL), with several small projecting granules on anterior margin. Suboculars 8, 4 th and 5 th separated by 5 th supralabial. Mental broader but shallower than rostral. Postmental larger than mental. Chinshields 3 pairs. Dorsal scales largest. Ventral scales and subdigital lamellae smooth. Adpressed limbs meeting. Digits moderately long, subcylindrical. Third front digit shorter than the 4 th.
Measurements (holotype with the variation shown in the paratypes /specimens examined in parentheses). SVL 70.1 (mean 77.9, range 68.0–92.0), HL 11.6 (mean 12.2, range 11.2–13.8), HW 6.6 (mean 7.1, range 6.4–8.1), AG 36.2 (mean 41.0, range 34.0–49.7), SF 27.5 (mean 29.3, range 27.0–32.4), S-Ear 14.8 (mean 14.8, range 14.0–15.7), EF 14.7 (mean 15.8, range 14.0–18.3), HLL 27.0 (mean 28.5, range 26.0–31.0), D-Ear 1.3 (mean 1.3, range 1.1–1.7).
Variation (holotype with the variation shown in the paratypes /specimens examined in parentheses). Upper ciliaries 7 (mean 7, range 5–8); lower ciliaries 12 (mean 10, range 8–12); nuchals 3 pair (mean 3 pairs, range 2–3 pairs); midbody scale rows 32 (mean 31, range 30–32); ventral scale rows 73 (mean 77, range 73–82); subdigital lamellae 22 (mean 21, range 19–22); supraciliaries 5L/6R (mean 5, range 5–6); suboculars 6 (mean 6, range 5–6). Frontonasal usually not separated from frontal by prefrontals meeting in midline. Anterior loreal always in contact with first and second supralabial, posterior loreal always in contact with second and third supralabial. Supralabials 7, the sixth the largest. Infralabials 6 (usual) or 7. Projecting scales usually present in ear opening. Maximum SVL 92.0 mm.
Two of the specimens examined had an intact tail, tail length of intact specimens ranging between 110 – 114 mm. Mean TL/ SVL = 1.40. Ratios for morphological measurements (+ SD): AG/SF 1.39 + 0.13; S-Ear/EF 0.94 + 0.07; HL/HW 1.72 + 0.24 (N=6).
Colouration. This is variable among specimens, but the most common colouration is as follows: Mid-dorsal stripe where present not usually continuous, but if continuous carries past base of tail. Dorsal surface mid brown, usually with light and dark flecking, 5–6 scale rows wide, grading into pale dorsolateral stripe extending from behind eye to base of tail. This pale stripe is bordered below by a ½ scale row wide dark brown band, below that a 2-scale wide lighter brown row, notched on upper and lower edges, running from behind nostril through eye towards base of tail and becoming indistinct towards tip of tail. This band may have lighter speckling. Then a darker brown band 1 half-scales wide. This lower dark brown band is bordered below by a pale stripe, 1 to 2 half-scale rows wide running from below the eye, through the ear, above the limbs to become indistinct after the hindlimbs. This band is notched above and below. Soles of feet cream/brown. Belly pale yellow, speckled with darker flecks. Throat pale, speckled. Outer surface of forelimbs brown, speckled with light and dark. Dorsal surface of head with few dark markings. Under surface of tail shades to grey from yellow. Juvenile colour unknown.
Etymology. The scientific name is derived from the meaning of aurora ‘of the dawn’ and the eastern location of the species. Suggested vernacular names are Hawke’s Bay skink, or eastern speckled skink.
Distribution. The species is recorded from the Hawke’s Bay region of the North Island, in the 34.01 Eastern Hawkes Bay Ecological District. This distribution is well southeast of what is termed as the ‘Taupo Line biogeographic barrier’; other O. aff. infrapunctatum records also exists for south of this line but their identities are not yet confirmed at specific level ( Chapple & Hitchmough 2016). This species is recorded from the coast to 180 m ASL. The species has been found in coastal dunes, grassland, low shrubland, scrubland and coastal forest edges ( van Winkel et al. 2018).
Natural History. Diurnal, strongly heliothermic, terrestrial. A large skink (up to 100 mm SVL, 23 g) that is known from coast and lowland habitats. Population studies have been undertaken at Cape Sanctuary by Victoria University of Wellington ( Bidinosti et al. 2008, Dent 2016, N. Nelson pers. comm.). Dent (2016) estimated the density of eastern speckled skinks to range between 880–990 / ha in exotic grassland and represented 97–99% of all skink captures at a small study site in Cape Sanctuary, but this population was apparently not increasing in response to predatory pest control. The range of these skinks within Cape Sanctuary is currently restricted to a few known grassland and duneland sites ( Bidinosti et al. 2008, Dent 2016). Sex ratios at this population are equal ( Dent 2016, T. Bell, unpub. data). From a large sample of individuals at this location, the mean SVL was 70 mm (range 30–100 mm), original tail length exceeds SVL by a ratio of 1.3, up to 130 mm; mean weight was 8.75 g (range 2–23g); and the percentage of tail loss was very high (81%) although these were typically represented as loss of tail tips (E. Dent, unpub. data; T. Bell, unpub. data). A single melanistic individual has been recorded in this population ( Wiles 2017).
Discussion. Specimens from five localities have been genotyped and are members of or close to Clade 4 of Greaves et al. (2008; Figure 2 View FIGURE 2 ). This clade originally included specimens from the coast near Whanganui. A specimen from Westport was sister to this clade and is separated by 2.9% sequence divergence ( Table 2 View TABLE 2 ). We have obtained ND2 sequences from additional specimens from Ngamatea Station, Kaimanawa Ranges, and from Cape Kidnappers, Hawkes Bay. The Ngamatea Station samples clustered most closely with the Whanganui coast clade (2.8% model corrected ND2 sequence divergence), and the Hawkes Bay samples with the Westport specimen (2.9% model corrected ND2 sequence divergence). An additional specimen labelled „Awarua Point“, but in our opinion clearly mislabelled, also clustered closely with the Hawkes Bay samples. DNA could not be extracted from a museum specimen from Waimarama, Hawke‘s Bay, but this locality is geographically close to Cape Kidnappers and the specimen is morphologically similar to the Cape Kidnappers ones. We have based this description on the Hawkes Bay populations only, recognising that the Whanganui Coast and Kaimanawas populations (5.3% divergent from the Hawkes Bay population, a deeper separation than that between O. salmo and O. albornense ) are likely to require description as a distinct species. These populations are also morphologically distinctive, in particular a specimen from Waiinu Beach seen by one of us (GBP) is quite different from any other members of the O. infrapunctatum group so far examined. However, we lack sufficient preserved material to fully assess or formally describe this potential species here. DNA could not be extracted from the Wairarapa museum specimens, and no live individuals have been found in the Wairarapa region since the 1970s, despite recent species-specific survey effort (T. Bell, unpub. data, 2018). These specimens show some morphological differences from the Cape Kidnappers ones and their taxonomic identity requires further work. The taxonomic status of the unique Westport specimen (2.9% divergent from the Cape Kidnappers population) also requires confirmation.
| NMNZ |
Museum of New Zealand Te Papa Tongarewa |
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