Ornithuroscincus pterophilus, Slavenko & Tamar & Tallowin & Kraus & Allison & Carranza & Meiri, 2022

ORNITHUROSCINCUS PTEROPHILUS View in CoL View at ENA SP. NOV.

MOUNT VICTORIA SMOOTH- EARED SKINK

( FIGS 16 View Figure 16 , 20–21 View Figure 20 View Figure 21 ; TABLE 1 View Table 1 )

Z o o b a n k r e g i s t r a t i o n: u r n:l s i d: z o o b a n k. org:act: 8D6F7129-1240-4F5A-B31E-0AD103CAA139

Holotype: BPBM 45705 (field tag AA 23742), adult female, collected by A. Allison at grasslands, 8.9592°S, 147.5745°E (WGS 84), 2813 m a.s.l., SE slopes of Mt Victoria , Northern (Oro) Province, Papua New Guinea, 15 August 2015. GoogleMaps

Paratypes (N = 17): Papua New Guinea: Central Province: Crest of Owen Stanley Mts along the Kokoda Track: 1900 Crossing Campsite , 9.1288°S, 147.7264°E (WGS 84), 1936 m a.s.l. (BPBM 44634–37, 44843–44, 44855; one male, three females, three juveniles); Myola 2 Guest House , 9.1509°S, 147.7675°E (WGS 84), 2076 m a.s.l. (BPBM 44859; juvnile); Northern (Oro) GoogleMaps Province: Chopper Pad Camp , 8.9738°S, 147.5697°E (WGS 84), 2680 m a.s.l. (BPBM 45669, 45710–11; one male, one female, one juvenile); grasslands, 8.9554°S, 147.5764°E (WGS 84), 2805 m a.s.l. (BPBM 45704; female); grasslands, 8.9594°S, 147.5740°E (WGS 84), 2820 m a.s.l. (BPBM 45706; juvenile); 8.9585°S, 147.5751°E (WGS 84), 2817 m a.s.l. (BPBM 45713; male); 8.9591°S, 147.5743°E (WGS 84), 2836 m a.s.l. (BPBM 45714; male); 8.9585°S, 147.5753°E (WGS 84), 2814 m a.s.l. (BPBM 45715; female); 8.95919°S, 147.5742°E (WGS 84), 2830 m a.s.l. (BPBM 45716; female) GoogleMaps .

Diagnosis: A medium-sized species of Ornithuroscincus (adult SVL 50.1–62.3 mm) characterized by the unique combination of short limbs (forelimbs 27.0–33.7% of SVL, hindlimbs 33.3–42.5% of SVL); frontoparietals unfused; nuchals 1–4 pairs; paravertebral scales 50–67; midbody scale rows 28–42; 4 th digit on front foot not longer than 3 rd; subdigital lamellae 17–23 under 4 th toe; single supradigital scales 3–8 on 4 th toe; dorsum light brown with two to four more-or-less transverse longitudinal rows of dark brown to black spots of varying width, at their widest giving the impression of black base coloration with light brown striations, often joining to create two transverse rows of dark spots along tail; dark brown to black lateral stripe or field present; dorsolateral stripes present as thin (up to a single scale wide), unfragmented or zigzag light brown stripes extending from orbital region to tail; flanks marked with parallel fragmented light brown to white vertical bars extending ventrally from dorsolateral stripes; uniform coloration on abdomen, thighs and precloacal region, light to dark blue in preservative, lime green in life; brown spotting occasionally occurs on thighs and precloacal region; ventral surface of tail light to dark blue in preservative, lemon yellow in life, with occasional brown spotting; palmar and plantar surfaces light to dark brown in preservative, light or dark brown to lemon yellow in life.

Comparisons: Ornithuroscincus pterophilus differs from O. bengaun in having unfused (vs. fused) frontoparietals. It further differs from O. albodorsalis , O. noctua , O. nototaenia and O. cf. venemai in lacking a parietal eye spot (vs. present). It differs from O. inornatus and O. cf. venemai in having a light brown dorsum with dark spots and thin (up to a single scale wide) light brown dorsolateral stripes that are clearly distinguished from the base dorsal coloration [vs. uniformly light brown dorsum with thick (one to two scales wide) light brown dorsolateral stripes, extending in thickness towards the base of the tail, diffusely demarcated from the base dorsal coloration in O. inornatus ; deep olive grey dorsum powdered with brown, with broad dorsolateral white stripes becoming broader posteriorly in O. cf. venemai ( Brongersma, 1953a) ]. Ornithuroscincus inornatus also lacks the parallel light brown vertical bars that occur on the flanks of O. pterophilus . It further differs from O. inornatus in slightly larger size (adult SVL 50.1–62.3 mm vs. 47.9 mm) and from O. cf. venemai by having a higher count of midbody scale rows (28–42 vs. 24–26; Brongersma, 1953a).

Ornithuroscincus pterophilus is most similar in coloration to O. sabini , from which it differs in having less pronounced dorsolateral stripes, a flank pattern composed of parallel fragmented vertical bars (vs. scattered specks in O. sabini ) and a blue (lime green in life) venter in preservative [vs. white venter in preservative (lemon yellow or white in life) in O. sabini ].

Description of the holotype: Rostral broad and shallow, wider than deep, projecting slightly onto top of snout; nasals more or less rectangular, separated by rostral and frontonasal contact, projecting anterodorsally onto dorsum of snout; nostril circular, centred within nasal; frontonasal large, with seven sides, extending laterally to slightly above the level of nares, in narrow contact with frontal; prefrontals large, separated by frontal and frontonasal contact, bordered ventrolaterally by two loreals; supraoculars four, anterior two in contact with frontal, posterior three in contact with frontoparietals; frontal wedge shaped, widest anteriorly; frontoparietals single pair in medial contact, in contact with posterior three supraoculars and anteriorly in contact with frontal; interparietal smaller than single frontoparietal, almost triangular shaped, widest anteriorly; parietal eye spot absent; parietals in contact behind interparietal, in contact anteriorly with frontoparietals, posteriormost supraocular and pretemporals; nuchals two pairs, transversely enlarged, at least twice as wide as long, anteriormost pair in contact with single secondary temporals. Anterior loreal similar in size to posterior loreal, both higher than long; lower preocular roughly square in shape; upper preocular much smaller, longer than high; presubocular single and rectangular in shape; postsuboculars two, lower interdigitated between subocular supralabial and penultimate supralabial; lower eyelid scaly, moveable, with a clear palpebral disc smaller than size of ear opening; supraciliaries eight, anteriormost in narrow contact with frontal, posteriormost projecting medially and interdigitated between posteriormost supraocular and upper pretemporal; primary temporal single, interdigitated between penultimate and posteriormost supralabial; secondary temporals two, upper larger and overlapping lower; supralabials seven, fifth in contact with small scales of lower eyelid; postsupralabials two; ear opening moderately large and oval shaped, without lobules. Mental single; postmental single, contacting two anteriormost infralabials; infralabials six; enlarged chin shields three pairs, the first pair in medial contact, second pair narrowly separated by a single medial scale, third pair separated by three medial scales; posteriormost chin shield in contact with penultimate infralabial. Body scales smooth, in 42 rows at midbody; paravertebral scales 60; medial precloacal scales enlarged, overlapping lateral precloacals. Scales on dorsal surface of 4th toe in two rows proximally, single row distally beginning at third interphalangeal joint, three single scales; subdigital lamellae under 4th toe 20, smooth. In preservative ( Fig. 20 View Figure 20 ), dorsum light brown, with four transverse longitudinal rows of small dark brown spots no more than a single scale wide, lateralmost rows in contact with dorsolateral stripes and composed of larger spots, one to two scales long; dark brown spots gradually become smaller posteriorly until tail surface becomes uniformly light brown; dorsolateral stripes present in zigzag formation, no more than a single scale wide, extending continuously from orbital region to base of tail; dorsolateral stripes bordered laterally by dark brown fields extending to above limbs, these bordered ventrally by light grey field, itself bordered ventrally by blue venter; lateral fields marked with parallel vertical bars of pale blue spots one to two scales wide and long, extending from dorsolateral stripes ventrally; head similar to dorsum, with dark scale margins and some dark brown spotting, particularly in parietal region; slightly lighter on snout and supraciliaries; labials dark brown at margins and pale blue in centre; venter pale blue, with light brown dusting on proximal third of tail, thighs and precloacal region; palmar surfaces light brown, plantar surfaces white, digits dark brown. In life ( Figs 16 View Figure 16 , 21 View Figure 21 ), dorsal colour light brown, with pale yellow to white dorsolateral stripes; lateral field black dorsally, light brown ventrally, diffusing to ventral surfaces, with parallel heavily fragmented vertical bars extending ventrally from dorsolateral stripes, made up of pale yellow spots; chest and abdomen lime green; ventral surfaces of proximal third of tail, thighs and precloacal region lemon yellow; ventral surface of distal twothirds of tail white; palmar and plantar surfaces lemon yellow to dark brown.

Variation: Adult body size 50.1–62.3 mm SVL (mean = 55.9, SD = 4.2, N = 12). Females (mean = 57.4, range = 51.6–62.3, SD = 3.8, N = 8) have larger average size than males (mean = 53.0, range = 50.1– 57.7, SD = 3.6, N = 4). Forelimbs 27.0–33.7% of SVL (mean = 30.4%, SD = 2.2, N = 12). Hindlimbs 33.3– 42.5% of SVL (mean = 38.0%, SD = 2.7, N = 12). Scale rows at midbody 28–42 (mean = 33.4, SD = 4.58, N = 18), with lower counts for specimens from the Kokoda Track (BPBM 44634–37, 44843–44, 44855 and 44859; range = 28–31) vs. Mt Victoria (BPBM 45669, 45704–06, 45710–11 and 45713–16; range = 30–42); paravertebral scales 50–67 (mean = 60.4, SD = 3.91, N = 18). Lamellae under 4th toe 17–23 (mean = 19.9, SD = 1.7, N = 18); single supradigital scales on 4th toe 4–8 (mean = 4.3, SD = 1.18, N = 18). Mostly 1–4 pairs of nuchals, but BPBM 44843 has two nuchals on left side and one on right and BPBM 44844 lacks nuchal on right side, with only single nuchal on left side. Nuchals typically wider than long but roughly as wide as long in BPBM 44635, 44844 and 45713. Primary nuchals usually separated from secondary temporals by single smaller intercalated scale (N = 13), rarely by two (N = 1) and occasionally by none (N = 4). Prefrontals either in narrow medial contact (N = 8) or separated by contact of frontal and frontonasal (N = 10). Nasal scale single in all but BPBM 44637, where nasal scale is divided by suture extending medioposteriorly from nostril. Presubocular almost always single (N = 16), but absent in BPBM 44843, and two in BPBM 44635. Supraciliaries either seven (N = 5) or eight (N = 13). Anteriormost supraciliary either in contact with frontal (N = 11) or not (N = 7). Postsuboculars usually two (N = 14), occasionally three (N = 4). Secondary temporals usually two (N = 13), but occasionally one (N = 4), and in BPBM 45713 three. Supralabials almost always seven (N = 16), rarely six (N = 2). Posteriormost supralabial fragmented by horizontal suture on left side in BPBM 44635. Infralabials usually six (N = 15), rarely seven (N = 2) or eight (N = 1).

Dark brown spots on dorsum vary from small and hardly distinguishable (BPBM 44855) to large enough to form the appearance of dark brown base coloration (BPBM 45669 and 45710). In general, populations from higher elevations on Mt Victoria (BPBM 45669– 716) have darker dorsal coloration than populations from lower elevations along the Kokoda Track (BPBM 44634–859). Dorsolateral stripes distinct in all but BPBM 44843 and 44845, in which they are indistinguishable in preservative, but were extremely pale in life.

Colour in life: Dorsal surfaces light to dark coppery brown, with small to large dark brown to black spots in two to four more-or-less transverse rows, often extending into two transverse rows along tail ( Figs 16 View Figure 16 , 21 View Figure 21 ). Dorsolateral stripes pale yellow. Sides dark brown to jet black, diffusely giving way ventrally to lighter brown, marked with parallel vertical bars of pale white spots. Venter uniform lime green, often with lemon yellow on tail, precloacal region and thighs. Yellow occasionally absent (BPBM 44843) and lime-green ventral coloration can be pale (BPBM 44843 and 45710). Chin often paler than abdomen. Ventral surfaces of tail and precloacal region occasionally marked with dark brown spots. Juveniles appear to have bright orange tails. Palmar and plantar surfaces light or dark brown to lemon yellow.

Etymology: Masculine Latinized compound adjective derived from the Greek pteris, fern, and philos, lover of, reflecting that most specimens collected on Mt Victoria were found sheltered between fronds of tree ferns.

Distribution: Known only from 1936–2836 m a.s.l. in the south-eastern Owen Stanley Mountains, Papua New Guinea. Currently two populations are known: one from the south-eastern slopes of Mt Victoria (2680–2840 m a.s.l.) and one from the crest of the Owen Stanley Mountains along the Kokoda Track, at “1900 Crossing” (9.1288°S, 147.7264°E; WGS 84) and a single specimen from the nearby Myola dry lake beds. Presumably, O. pterophilus occurs more broadly around Mt Victoria in suitable habitats, but its exact distribution remains to be determined. Nevertheless, it is likely that, similar to most other species of Ornithuroscincus , its overall distribution is narrow.

Natural history: On Mt Victoria , most animals were found in the Isuani Basin high-elevation grassland (> 2800 m a.s.l.), dominated by Gleichenia vulcanica Blume ferns, together with a variety of grasses and sedges, particularly Calamagrostis , Danthonia , Deschampsia , Gahnia and Poa together with Astelia (Asteliaceae) . There are clumps of shrubs, particularly on the grassland margins, dominated by Gaultheria mundula F.Muell. , Dimorphanthera spp. , Rhododendron spp. , Vaccinium amblyandrum F.Muell , Acrothamnus suaveolens (Hook.f.) Quinn and Hypericum spp. Animals were found sheltered between fronds of tree ferns ( Alsophila spp. ) during daytime hours, with air temperatures between 17 and 18°C. Animals were not observed as active, but this may have been due to drought conditions induced by the 2015–16 El Niño.

Three animals were collected from regenerating cloud forest at slightly lower elevations (“Chopper Pad Camp”, 2680 m a.s.l.), also under shelter. The area had apparently been cleared 5–10 years previously and was dominated by second growth, particularly Decaspermum sp. and other myrtaceous shrubs and small trees. Nearby mature cloud forest was dominated by the conifer, Dacrycarpus compactus (Wasscher) de Laub. , which forms nearly pure stands in many areas fringing the grassland.

Reproduction: Viviparous. Litter size varies between 2–3 (mean 2.3, N = 4).

Conservationstatus: Populationsizeandtrendunknown, but animals were not abundant in sampled localities. Based on the populations sampled herein, O. pterophilus has an extent of occurrence of 156 km 2 and an area of occupancy of 20 km 2 (based on occupation of 4 km 2 cells; both calculated using http://geocat.kew.org/). It does not occur near any protected areas. The species appears to be most common in high-elevation grasslands, and the availability of such habitats would therefore greatly impact its exact distribution boundaries. Shortly after the type series was collected there, the grasslands on Mt Victoria experienced extensive anthropogenically-caused bushfires exacerbated by a drought induced by the 2015–2016 El Niño. This likely damaged the habitat and thus the population there. Future warming and severe ENSO events due to climate change are likely to cause continued degradation of suitable habitat. Therefore, we recommend assigning a status of Endangered B1ab(iii) to O. pterophilus .