Oligosoma repens, Chapple, David G., Bell, Trent P., Chapple, Stephanie N. J., Miller, Kimberly A., Daugherty, Charles H. & Patterson, Geoff B., 2011
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publication ID |
https://doi.org/ 10.5281/zenodo.205462 |
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DOI |
https://doi.org/10.5281/zenodo.6182748 |
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persistent identifier |
https://treatment.plazi.org/id/03AC4C11-8D3A-A42E-FF4C-FBD9FE5D4F82 |
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treatment provided by |
Plazi |
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scientific name |
Oligosoma repens |
| status |
sp. nov. |
Oligosoma repens sp. nov.
Figure 9 View FIGURE 9. a
Oligosoma inconspicuum Jewell 2008: 88
Holotype. Mt Nicholas Road, Eyre Mountains, (45º 15’S, 168º 18’E), RE007279, adult male (coll. T. Bell, 2009).
Paratypes (8 specimens). Cascade Creek, Eyre Mountains (45º 13’S, 168º 26’E), 5 specimens (RE007282, female; RE007285, male; RE007287, male; RE007292, female; RE007294, male) (coll. J. Reardon, January 2010); Lower Nevis Valley (45º 10’S, 168º 57’E), 3 specimens (RE007291, male; RE007295, male; RE007296, male) (coll. B. Barratt, December 2009 – January 2010).
Diagnosis. Oligosoma repens can be distinguished from other related Oligosoma species through a combination of characters ( Figure 4 View FIGURE 4 a – b ). Compared to O. maccanni , O. repens has a glossy appearance, with brown predominating whereas O. maccanni has a greyer ground colour. Oligosoma maccanni has a pale grey ventral colour rather than the bright yellow ventral colour in O. repens . The ear opening in O. maccanni often has large projecting scales on the interior margin, whereas these are often minimal or lacking altogether in O. repens . Oligosoma maccanni has four supraocular scales compared with three in O. repens . Oligosoma polychroma from nearby areas have very similar colour patterns to O. repens , but can be distinguished by a pale dorsal stripe on the outside of the forelimbs, and a greyish-brown ventral colouration. The ear opening in O. polychroma often has prominent projecting scales on the interior margin. There are statistical differences between O. repens and O. toka (SVL/HL, SVL/HLL, ventral scales), O. burganae (AG/SF, SE/EF, HL/HW, SVL/HL), and O. notosaurus (SVL/HL, ventral scales) ( Figure 4 View FIGURE 4 a – b ). All O. repens have three supraoculars whereas all O. inconspicuum and O. notosaurus have four. The number of subdigital lamellae in O. tekakahu (16) is fewer than O. repens (19–23). The dorsal surface of the head is usually unmarked in O. repens , in contrast with O. toka and O. notosaurus in particular. The species is more gracile than the other members of the species complex.
Description of holotype. Body elongate, oval in cross-section; limbs moderately well-developed, pentadactyl. Lower eyelid with a transparent palpebral disc, bordered on sides and below by small, oblong granules. Nostril centred just below middle of nasal, pointing up and back, not touching bottom edge of nasal. Supranasals absent. Rostral broader than deep. Frontonasal broader than long, 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 3, the second is the largest. Frontoparietals distinct, larger than interparietal. A pair of parietals meeting behind interparietal and bordered posteriorly by a pair each of nuchals and temporals, also in contact with interparietal, frontoparietal, third supraocular and 2 postoculars. Loreals 2, similar size; anterior loreal in contact with first and second supralabial, posterior loreal, prefrontal, frontonasal and nasal; posterior loreal in contact with second and third supralabial, first subocular, upper and lower preocular, prefrontal and anterior loreal. Supralabials 7, the sixth and seventh are the equal largest. Infralabials 6, several of them equal in size; fifth supralabial below centre of eye. Mental broader but shallower than rostral. Suboculars separated by fifth supralabial. Chinshields 3 pairs. One primary temporal, approximately half the size of lower secondary temporal. Dorsal scales similar in size to ventral scales, weakly striate. Ventral scales smooth. Subdigital lamellae smooth. Ear opening round, small with insignificant projecting granules. Forelimbs shorter than hindlimbs. Adpressed limbs not meeting in adult. Digits long, sub-cylindrical. Third front digit shorter than the fourth.
Measurements (in mm; holotype with the variation shown in the type series in parentheses). SVL 56.4 (mean 55.1, range 47.6–61.8), HL 8.0 (mean 8.0, range 7.0–9.1), HW 5.7 (mean 5.6, range 4.7–6.0), AG 28.7 (mean 28.8, range 23.6–33.8), SF 20.8 (mean 20.3, range 17.6–22.6), SE 10.5 (mean 10.1, range 9.0–11.3), EF 10.0 (mean 10.4, range 9.1–12.0), and TL unknown (mean 66.5, range 65.0–67.9, N=2).
Variation (holotype with the variation shown in the type series in parentheses). Upper ciliaries 6 (mean 7, range 5–7); lower ciliaries 10 (mean 9, range 7–10); nuchals 0 pairs (mean 2 pairs, range 0–3 pairs); midbody scale rows 32 (mean 32, range 30–34); ventral scale rows 77 (mean 76, range 68–81); subdigital lamellae 22 (mean 21, range 19–23); supraciliaries 6 (mean 6, range 6–7); suboculars 7 (mean 7, range 6–9). Frontonasal seldom separated from frontal by prefrontals meeting in midline. Anterior loreal in contact with first or second supralabial. Secondary loreal usually in contact with secondary and third supralabial. Supralabials 7, the fifth or sixth are the largest. Infralabials 5 or 6 (usual). Third front digit shorter (usual) or as long as the fourth. Maximum SVL 61.8 mm. Two specimens had intact tails (TL/SVL = 1.28). Ratios for morphological measurements (± SD): AG/SF 1.42 ± 0.07; SE/EF 0.98 ± 0.07; HL/HW 1.43 ± 0.07.
Colouration. Dorsal surface yellowish brown often with a median dorsal very dark brown longitudinal stripe, 2 half-scale rows wide, well or partially developed, commencing behind the head and passing back to the base of the tail. A yellowish brown dorsal band 2 half-scale to 1.5 scale rows wide sometimes with light flecks. Another broken dark brown band, 1 half- to 2 half-scale rows wide, shading on to a pale dorsolateral band 1 half- to 2 halfscale rows wide. This pale dorsolateral band, extending from above and behind posterior margin of eye to base of tail. This stripe bordered laterally by a strong yellowish brown band 1–2 scale rows wide, originating behind nostril, passing through eye and ending past base of tail, bordered laterally by a dark yellowish brown band. The strong yellowish band sometimes flecked with white and dark brown. Below this an indistinct pale stripe passes from beneath the posterior border of the eye through the ear, above the limbs to the base of the tail. This stripe is irregularly defined below by brown scales which merge gradually with the yellow ventral colouration. Ventral surface may be lightly speckled with black spots on chin and throat, which are white. Outer surface of forelimbs is dark brown with black and white specks. Juvenile colouration similar to adult, but generally lighter. There do not appear to be sexually dimorphic colour patterns. Dorsal surface of head normally unmarked.
Etymology. From ‘repens’ (Latin, neuter) = unexpected. Refers to the unexpected discovery of a genetically divergent new species in the Eyre Mountains that occurs sympatrically with O. inconspicuum (sensu stricto). The common name is the Eyres skink.
Habitat and life history. The extent of its distribution is unknown, but Oligosoma repens appears to be confined to the Eyre Mountains and also the Hector Mountains (MAVORA 73.02 Eyre; WAIKAIA 74.01 Nokomai; McEwen 1987) of western Otago ( Figure 5 View FIGURE 5 f). Environmental classifications for the Eyres are O1 and Q1 and, for the Hector Mountains, Q1 and Q2 ( Leathwick et al. 2003). Oligosoma repens appears to be abundant around rock piles and screes along the Eyre Mountains foothills (~ 700 m asl, and likely higher), but less abundant elsewhere where cover is scarce on the open Eyre valley flats, except where screes occur. The Eyre Ecological District consists of highly dissected, steep and eroding schist or greywacke mountains with narrow valley floors (ranging from 600–2025 m asl) ( McEwen 1987). The climate of the Eyres ED is cool and moderately wet (annual rainfall 800– 1200 mm); snow may accumulate above 1000 m asl during winter. Much of the Eyres ED was once beech forest, but have been converted to a mixture of exotic pastoral grasslands and native fescue, red or snow tussockland ( McEwen 1987). The skink is sympatric with O. inconspicuum , O. maccanni , and the gecko Hoplodacylus sp. ‘Otago Large’, another undescribed taxon within the H. maculatus species-complex. Oligosoma chloronoton may also be a sympatric species ( McEwen 1987), as well as O. polychroma .
Conservation status. Little is known about the range, abundance and population viability of O. repens . It is currently considered Not Threatened (Range Restricted) in the New Zealand Department of Conservation’s national threat classification lists ( Hitchmough et al. 2010). Further research will be required to assess the conservation status of O. repens .
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