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

Slavenko, Alex, Tamar, Karin, Tallowin, Oliver J S, Kraus, Fred, Allison, Allen, Carranza, Salvador & Meiri, Shai, 2022, Revision of the montane New Guinean skink genus Lobulia (Squamata: Scincidae), with the description of four new genera and nine new species, Zoological Journal of the Linnean Society 195 (1), pp. 220-278 : 268-270

ORNITHUROSCINCUS VIRIDIS SP. NOV.

GREEN SMOOTH- EARED SKINK

( FIGS 16 , 23–24 ; 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: 1D260000-8B53-4698-ADC4-A0374C1FD2C1

Holotype: BPBM 44744 (field tag AA 23450), gravid adult female with two embryos, collected by O. Tallowin at Myola 2, 9.1509°S, 147.7678°E (WGS 84), 2075 m a.s.l., crest of Owen Stanley Mts along the Kokoda Track, Central Province, Papua New Guinea, 5 April 2014.

Paratypes (N = 16): Papua New Guinea: Central Province: Crest of Owen Stanley Mts along the Kokoda Track: Myola 2 Guest House , 9.1509°S, 147.7675°E (WGS 84), 2076 m a.s.l. (BPBM 44729–38; four males, five females, one juvenile) ; Myola 1, 9.1508°S, 147.7675°E (WGS 84), 2057 m a.s.l. (BPBM 44739; female) ; Myola 1, 9.1506°S, 147.7672°E (WGS 84), 2072 m a.s.l. (BPBM 44740; male) ; Myola 1, 9.1509°S, 147.7675°E (WGS 84), 2076 m a.s.l. (BPBM 44741–42; two males) ; same locality as holotype (BPBM 44743; male) ; Myola 2, 9.1509°S, 147.7679°E (WGS 84), 2076 m a.s.l. (BPBM 44745; male) .

Diagnosis: A medium-sized species of Ornithuroscincus (adult SVL 42.1–54.8 mm) characterized by the unique combination of short limbs (forelimbs 25.7–30.8% of SVL, hindlimbs 29.0–40.6% of SVL); frontoparietals unfused; nuchals 1–3 pairs; paravertebral scales 57–70; mid-body scale rows 32–41; 4 th digit on front foot not longer than 3 rd; subdigital lamellae 12–18 under 4 th toe; single supradigital scales 3–5 on 4 th toe; dorsal coloration light to dark brown in preservative, light to dark greenish brown in life; dark brown to black lateral field present; dorsolateral stripes absent; flanks speckled with spots no more than a single scale wide, blue in preservative, green in life; uniform coloration on abdomen, thighs and precloacal region that lacks brown spotting, light blue in preservative, bright green in life; tail uniformly light blue more or less speckled with light brown spots; palmar and plantar surfaces brown.

Comparisons: Ornithuroscincus . viridis differs from all other species of Ornithuroscincus in lacking dorsolateral stripes, having shorter relative limb length (forelimbs 25.7–30.8% of SVL and hindlimbs 29.0–40.6% of SVL vs. forelimbs 27.0–36.3% of SVL and hindlimbs 33.3– 47.3% of SVL) and a lower average count of subdigital lamellae under 4 th toe (15.8, range = 12–18 vs. 20.2, range = 17–23). It further differs from O. bengaun and O. shearmani in having unfused (vs. fused) frontoparietals. It further differs from O. albodorsalis , O. noctua , O. nototaenia and O. cf. venemai by lacking a parietal eye spot (vs. present) and by having a higher count of midbody scale rows [32–41 vs. 22–26, 23–28, 24–25 and 24–26, respectively ( Brongersma, 1953a; Zweifel, 1979; Shea & Greer, 2002)].

Ornithuroscincus viridis is most similar in body proportions and scalation to its sister species, O. pterophilus . However, it differs by being slightly smaller on average (mean adult SVL 49.7 mm, range = 42.1–54.8 vs. 55.9 mm, range = 50.1–62.3), in having shorter relative limb length (mean forelimbs 28.2% of SVL, range = 25.7–30.8 and hindlimbs 35.0% of SVL, range = 29.0–40.6 vs. mean forelimbs 30.4% of SVL, range = 27.0–33.7 and hindlimbs 38.0% of SVL, range = 33.3–42.5), a lower average count of subdigital lamellae under the 4 th toe (15.8, range = 12–18 vs. 19.9, range = 17–23), primary nuchal scales being usually as wide as long (15 of 17) vs. wider than long (15 of 18), and most easily by colour pattern: O. viridis lacks dorsolateral stripes (vs. present in O. pterophilus ), has uniform light to dark brown dorsal coloration (vs. light brown spotted with dark brown to black spots) and in life has a slight greenish tint to its dorsal coloration and bright green ventral surfaces (vs. lime green usually with lemon yellow on precloacal region and thighs).

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 (slightly closer to supralabials than to frontonasal); frontonasal large, with seven sides, extending laterally to slightly above the level of nares, not contacting frontal; prefrontals large, in narrow medial contact, bordered ventrolaterally by two loreals; supraoculars four, anterior two in contact with frontal, posterior three in contact with frontoparietals; frontal kite shaped, widest anteriorly; frontoparietals single pair in medial contact, in narrow contact with frontal; interparietal of roughly similar area to single frontoparietal, kite shaped, widest anteriorly; parietal eye spot absent; parietals in contact behind interparietal, in contact anteriorly with frontoparietals, posteriormost supraocular and two pretemporals; nuchals single pair, transversely enlarged, irregularly shaped, roughly as wide as long, separated from secondary temporal by a single intercalated scale. 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; postsuboculars three, lowest interdigitated between subocular supralabial and penultimate supralabial; lower eyelid scaly, moveable, with a clear palpebral disc smaller than size of ear opening; supraciliaries seven, anteriormost not in contact with frontal, posteriormost projecting medially and interdigitated between posteriormost supraocular and upper pretemporal; primary temporal single, interdigitated between posterior two supralabials; 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 single medial scale, third pair separated by three medial scales; posteriormost chin shield in contact with penultimate infralabial. Body scales smooth, in 33 rows at midbody; paravertebral scales 70; medial precloacal scales enlarged, overlapping lateral precloacals. Scales on dorsal surface of fourth toe in two rows proximally, single row distally beginning at third interphalangeal joint, five single scales; subdigital lamellae on fourth toe 18, smooth. In preservative ( Fig. 23 ), dorsum uniform light brown; dorsolateral stripes absent; dorsal pattern sharply replaced by dark brown lateral fields, gradually becoming lighter ventrally; lateral field speckled with multiple pale blue spots one scale wide; head similar in coloration to dorsum, slightly lighter on snout and supraciliaries; labials dark brown at margins, pale blue in centre; venter pale blue with slight brown dusting at edges of scales laterally; light brown dusting more pronounced under tail; palmar and plantar surfaces dark brown. In life ( Figs 16 , 24 ), dorsum dark brown with green tint, becoming lighter dorsolaterally; lateral field black, speckled with multiple green spots a single scale wide, specks extending to margins of dorsal field; venter bright green, lemon yellow under tail; palmar and plantar surfaces dark brown.

Variation: Adult body size 42.1–54.8 mm SVL (mean = 49.7, SD = 3.7, N = 16). Females (mean = 49.9, range = 42.1–54.8, SD = 4.8, N = 7) and males (mean = 49.5, range = 44.1–53.4, SD = 2.9, N = 9) of similar size. Forelimbs 25.7–30.8% of SVL (mean = 28.2%, SD = 1.5, N = 16). Hindlimbs 29.0– 40.6% of SVL (mean = 35.0%, SD = 2.6, N = 16). Scale rows at midbody 32–41 (mean = 36.2, SD = 2.7, N = 17); paravertebral scales 57–70 (mean = 62.8, SD = 3, N = 17). Lamellae under fourth toe 12–18 (mean = 15.8, SD = 1.59, N = 17); single supradigital scales on 4th toe 3–5 (mean = 3.4, SD = 0.7, N = 17). Mostly 1–3 pairs of nuchals, but BPBM 44734 lacks nuchal on left side, with only single nuchal on right side. Nuchals typically roughly as wide as long (N = 15), rarely wider than long (N = 2). Primary nuchals usually separated from secondary temporals by a single smaller intercalated scale (N = 13), rarely by two (N = 2) or none (N = 2). Prefrontals in medial contact in all but BPBM 44733, where separated by a single, azygous scale. Loreals two in all but BPBM 44740, where loreal single. Supraciliaries either seven (N = 7) or eight (N = 8), rarely nine (N = 2). Anteriormost supraciliary either in contact with frontal (N = 9) or not (N = 8). Posteriormost supraciliary usually projecting medially (N = 15), but rarely in line with all other supraciliaries (N = 2). Postsuboculars usually two (N = 14), rarely three (N = 3). Secondary temporals usually two (N = 13), but rarely one (N = 2) or three (N = 2). Posteriormost supralabial fragmented by horizontal suture on left side in three specimens (BPBM 44729, 44740 and 44743). Infralabials either six (N = 12) or seven (N = 5). Infralabials posterior to contact with chin shields usually one (N = 14), rarely two (N = 2) or three (N = 1).

Colour pattern of all specimens generally similar to holotype, with few exceptions. BPBM 44732, 44737, 44741 and 44743 have sparse dark brown spotting on dorsum extending to tail, most pronounced in BPBM 44743. BPBM 44743 has a coppery brown dorsum with light margins, bordered medially by dark brown spotting, creating the appearance of light dorsolateral stripes. Palmar and plantar surfaces of BPBM 44735– 36 lighter brown.

Colour in life: Dorsum light to dark brown, often with green tint, usually uniform but rarely with sparse dark brown spotting ( Figs 16 , 24 ). Green tint not extending to tail, which remains brown. Sides dark brown to jet black, sharply demarcated from dorsum and speckled lightly or heavily with bright green spots a single scale wide. Sides becoming gradually lighter towards venter, dark lateral field of varying width. Venter uniformly bright green, less pronounced on tail and often changing to lemon yellow, with light brown dusting laterally, more pronounced under tail.

Etymology: From the Latin single-ending adjective viridis , green, in reference to the diagnostic coloration of the species in life.

Distribution: Knownonlyfromhigh-elevationgrasslands at 2052–2076 m a.s.l. on the crest of the Owen Stanley Mountains in the Myola dry lakebeds along the Kokoda Track. Little is known about its distribution elsewhere, but it appears to be absent from nearby montane habitats (e.g. 1900 Crossing, 9.1288°S, 147.7264°E; WGS 84), as well as from similar high-elevation grasslands on the southern slopes of Mt Victoria , both localities where its sister species, O. pterophilus , occurs.

Natural history: All of our specimens of O. viridis were collected from underneath logs at the edge of a large (c. 800 ha) expanse of partially swampy grassland that is generally interpreted as an ancient lake bed that has filled in with sediment. The grasses include a mixture of native and introduced species, namely Anthoxanthum horsfieldii (Kunth ex Benn.) Reeder , Capillipedium parviflorum (R.Br.) Stapf , Dimeria chloridiformis (Gaudich.) K.Schum. & Lauterb. , Isachne myosotis Nees , Miscanthus floridulus (Labill.) Warb. ex K.Schum. & Lauterb. , Paspalum scrobiculatum L. and Sacciolepis indica (L.) Chase. These grasses, together with a rich array of sedges, formed a continuous, generally low ground cover that was similar in overall aspect to a temperate meadow. This formation, which is unusual in montane New Guinea, has a different appearance from the high-elevation tussock grasslands that dominate most alpine regions.

The area where the lizards were collected was bordered by a rich, upper montane forest about 15–25 m tall, with an uneven canopy. Aspect dominant species of trees included Saurauia sp. , Opocunonia nymanii (K.Schum.) Schltr. , Elaeocarpus angustifolius Blume , Elaeocarpus fuscoides Knuth , Elaeocarpus murukkai Coode , Elaeocarpus sayeri F.Muell. , Elaeocarpus trichophyllus A.C.Sm. , Sloanea tieghemii (F.Muell.) A.C.Sm. , Lithocarpus lauterbachii (Seemen) Markgr. , Lithocarpus rufovillosus (Markgr.) Rehder , Galbulimima sp. , Litsea albida (Kosterm.) Kosterm. , Syzygium benjaminum Diels , Syzygium callianthum Merr. & L.M.Perry , Syzygium homichlophilum Diels , Syzygium subalatum (Ridl.) Merr. & L.M.Perry , Pandanus spp. , Melicope conjugata T.G.Hartley , Melicope rubra (K.Schum. & Lauterb.) T.G.Hartley , Melicope stellulata T.G.Hartley and Archboldiodendron sp. Pulle’s southern beech, Nothofagus pullei Steenis , occurs on some steep ridges. The understory includes Decaspermum exiguum Merr. & L.M.Perry , Tasmannia piperita (Hook.f.) Miers and a rich array of Ericaceae .

We visited the area during inclement weather and did not observe the lizards when they were active. We found them only under logs in the grassland, not in the adjacent forest. We therefore infer that they are a grassland species.

Reproduction: Viviparous. Litter size of all three gravid females 2.

Conservation status: The species is locally abundant at the type locality, although the population trend is unknown. It does not occur near any protected areas. We did not find it in other grasslands in the overall area, including another ancient grassland-filled lakebed that was located nearby at a slightly lower elevation. This, along with its apparent absence from nearby localities where sympatric lizard taxa occur (such as O. pterophilus or Papuascincus sp. ), would suggest this species may have a restricted distribution, limited to the c. 800 ha grassland. Local landowners, accompanied by dogs, are with increasing frequency establishing hunting camps in the area. Feral pigs were observed foraging nearby. Dogs and pigs are both known to prey on the lizards. Given the relatively small area of occurrence of O. viridis and these threats from introduced predators, we recommend assigning a status of Vulnerable D2 to it.

Figures

Figure 16. Pictures in life of (A) Ornithuroscincus bengaun (holotype; BPBM 37741); (B) Ornithuroscincus pterophilus (holotype; BPBM 45705); (C) Ornithuroscincus sabini (BPBM 16761); (D) Ornithuroscincus shearmani (holotype; BPBM 47951); (E) Ornithuroscincus viridis (holotype; BPBM 44744). Images A, C by Fred Kraus, images B, D, E by Allen Allison.

Figure 23. Ornithuroscincus viridis holotype (BPBM 44744), in (A) dorsal view, (B) ventral view, (C) lateral view of head, (D) dorsal view of head and (E) ventral view of head. Images by Alex Slavenko.

Figure 24. Ornithuroscincus viridis holotype (BPBM 44744) in life, in (A) dorsal view and (B) ventral view. Images by Allen Allison.