Cyrtodactylus manos, Oliver & Karkkainen & Rösler & Richards, 2019

Oliver, Paul M., Karkkainen, Denise Taimi, Rösler, Herbert & Richards, Stephen J., 2019, A new species of Cyrtodactylus (Squamata: Gekkonidae) from central New Guinea, Zootaxa 4671 (1), pp. 119-128 : 120-124

Cyrtodactylus manos sp. nov.

urn:lsid:zoobank.org:act:EF2B60F0-6F45-459F-92D0-F20417FB663C

Yellow-snouted bent-toed gecko

Figs. 1–2

Cyrtodactylus sp. Rösler et al. 2007, p. 207

Cyrtodactylus ‘Gobe Ridge’ Oliver et al. 2012a, p. 439

Cyrtodactylus sp. ‘Gobe Ridge’ Tallowin et al. 2018, p. 33

Holotype. SAMA R62654 (Field number JCUNQ2462 ), adult female with partially regrown tail, Papua New Guinea: Southern Highlands Province, road east of Gobe Ridge Camp , 855 m. a.s.l. (143.7743ºE, 6.8145ºS); with ethanol preserved tissue for genetic analysis stored in the Australian Biological Tissues Collection (under registration number ABTC98417 ), collected by Stephen Richards and Daniel Wemp on 29 October 2001.

Diagnosis. Cyrtodactylus manos sp. nov. can be distinguished from all other Melanesian Cyrtodactylus by its unique combination of: small size (SVL to 75 mm); narrow head (HW/SVL 0.17); ventrolateral fold scalation homogeneous and lacking enlarged tubercles; forelimbs without tubercles; dorsal tubercles in 16–18 longitudinal rows at mid-body; ventral scales in approximately 46 longitudinal rows at mid-body; subcaudal scales not transversely widened or enlarged on original tail; largest precloacal scales roughly triangular and> 10 rows anterior to cloaca; enlarged femoral scales extending to knee, discontinuous with enlarged precloacals, ovoid and approximately twice as long as wide; and dorsal colour pattern on torso consisting of 11 dark-brown transverse irregularly-shaped dorsal bands or series of blotches ( Fig. 1 ).

Description of holotype. Adult female with two oocytes each 4.9 mm in length; body size small for a Melanesian Cyrtodactylus (SVL 73 mm; reported as 75 mm in Rösler et al. 2007, suggesting shrinkage in preservative) and habitus slender. Head long (HL/SVL 0.24), narrow (HW/SVL 0.17), clearly distinct from neck ( Fig. 1 ). Snout shorter than broad, rounded in dorsal profile, truncate in lateral profile; loreal region slightly inflated; interorbital region and top of snout concave; canthus rostralis rounded, weakly defined; eye-naris distance effectively same as orbit diameter (EN/OrB 0.98). Eyes large (OrB/HL 0.34), pupil vertical; supraciliaries extending from anteroventral to posterodorsal edge of orbit, longest at the anterodorsal margin. Ear opening trapezoidal, bordered above by small but distinct dorsal skin fold.

Rostral broadly pentagonal, wider than high, bordered dorsally by two small rounded supranasals and five internasals (two larger and transversely widened, and three tiny and granular). Nares bordered by first supralabial, rostral, supranasal, and five (left) or six (right) granular postnasals. Supralabials generally wider than high, 12 to rictus of jaw on right side, 10 on left side, 10 to midpoint of eye on right side, nine on left. Head, temporal and nu- chal scales small and granular, in nuchal and temporal regions these are interspersed with numerous low, rounded tubercles approximately 2–3 times the width of surrounding granular scales. Ten (right) and 11 (left) enlarged in- fralabials, generally wider than high, becoming narrower towards anterior and posterior ends of lower jaw, bordered by numerous rows of slightly enlarged scales grading into smaller granular gular scales. Mental wider than long, broadly triangular and slightly constricted at point of contact with four postmentals; outer postmentals large and in contact with the first infralabial; inner postmentals of same size as bordering gular granules.

Body gracile; trunk nearly half of body length (Trk/SVL 0.48), with ventrolateral folds. Dorsum at mid body with 16–18 rows of tubercles up to three times wider than surrounding small granular scales. Ventral scales much larger than dorsal scales, increasing in size medially, arranged in approximately 46 rows at midpoint of body. Precloacal region with numerous rows of roughly triangular or rounded enlarged scales, tapering in size gradually from largest located approximately 15 scale rows anterior to cloaca to much smaller scales bordering cloaca. Enlarged ovoid femoral scales roughly twice as long as wide, in series discontinous from enlarged precloacals, and extending from knee to almost level with point of limb insertion ( Fig. 2 ).

Limbs slender, forelimbs (FA/SVL 0.15) shorter and less robust than hindlimbs (HDL/SVL 0.18). Lateral and dorsal surfaces of upper and lower hindlimb with numerous low, rounded tubercles of 2–3 times the size of surrounding granular scales. Digits long and well developed, inflected at basal interphalangeal joints; subdigital lamallae smooth, rounded, undivided and expanded proximal to digital inflection (7–8–8–8–6 manus; 7–10–11–11 –8 pes); narrow distal to digital inflection (8– 9–12–12–11 manus; 7– 9–11–13–11 pes); large recurved claws sheathed by a dorsal and ventral scale.

Tail thin and partially regrown, 37 mm original, 42 mm regenerated; original tail with an indistinct broad dorsal furrow extending full length, caudal scalation irregular, grading from smaller dorsal scales to larger ventral scales, and tubercles on dorsal and lateral surfaces at the base; regrown tail with poorly distinguished and highly irregular scalation; post-cloacal spurs rounded, three on the right side and four on the left.

Colouration in preservative. Base colouration of dorsal surfaces light-brown. Dorsum with 11 dark-brown transverse irregularly-shaped dorsal bands or series of blotches (not including nuchal band) extending from neck to cloaca, becoming increasingly irregular towards posterior of torso; numerous tiny dark-brown maculations distributed across dorsum giving an overall medium-brown wash. Dorsal tubercles light-brown. Top of head with limited irregular-shaped medium-brown mottling, both sides of head with indistinct postorbital blotches. Snout variegated with medium- to light-brown, with the palest brown regions appearing as spots. Supracilaries very light-brown in dorsal view, but dark-brown, almost black when viewed from below. Limbs and toes light-brown, extensively varie- gated with medium- to dark-brown. Ventral ground colouration buff, with extensive and relatively homogenous tiny medium-brown maculations. Original tail light-brown dorsally with four irregularly-shaped dark-brown bands and further larger blotches and smaller flecks of dark-brown between these bands; ventrally buff with medium-brown variegations and extensive dark-brown maculations of varying density. Regrown tail relatively uniform mediumbrown.

Colouration in life. Base dorsal and lateral colouration on head, neck, trunk and limbs overall brownish-yellow, overlain with medium- to dark-brown transverse bands, blotches and maculations ( Fig. 1 ). Postorbital stripe dark-brown and meandering, more distinct in life than in preservative. Yellowish colouration prominent on dorsal tubercles, supracilaries, supralabials, infralabials and across the surface of the snout, where it forms numerous spots surrounded by darker-brown regions. Iris is bluish-grey with extensive black reticulations and thin yellowish margin along the pupil. Original tail with alternating dark-brown (four) and light (three) bands, two anteriormost light bands greenish-yellow, posteriormost light band greenish-white. Regrown tail dark-brown with dense yellowish flecking along the dorsal surface and additional sparse light-whitish flecking laterally.

Measurements of holotype. SVL 73, TL 79, OT 37, TrK 35.3, HW 12.6, HH 9.3, HL 17.4, EN 5.8, IN 3.1, OrB 5.9, EAR 1.7, FA 10.7, HDL 12.9. Meristics: SUPR 12R/10L (10/9 to midpoint of eyes), INFR 10R/11L, DTR 16–18, VENT 46. Toe I LAM 7 expanded 7 narrow, Toe IV LAM 11 expanded 13 narrow, PCTUB 4L/3R.

Comparisons. Cyrtodactylus manos sp. nov. can be distinguished from the ‘giant’ (maximum SVL> 126 mm: Oliver et al. 2014), Melanesian Cyrtodactylus in the C. loriae , C. louisiadensis and C. novaeguineae groups (sensu Tallowin et al. 2018) by the combination of its small adult size (SVL <80 mm), dorsal pattern of numerous transverse dark markings (> 6 versus <6), absence of enlarged tubercles on the ventrolateral folds (versus present), and absence of tubercles on the forelimbs (versus present and numerous). Cyrtodactylus manos sp. nov. further differs from members of the C. louisiadensis group in lacking transversely enlarged subcaudal scales (versus present), and from the C. novaeguineae species complex (sensu Oliver et al. 2016) by the absence (versus presence) of ventral tubercles on the throat and along the ventrolateral folds.

Cyrtodactylus manos sp. nov. differs from both of the two remaining smaller species in the C. novaeguineae group ( C. aaroni Günther and Rösler and C. mimikanus Boulenger ) in its combination of smaller body size (maximum SVL 75 mm versus 86.5 mm for C. aaroni and 103 mm for C. mimikanus ), in lacking transversely widened subcaudal scales (versus present), in lacking enlarged tubercles on the ventrolateral fold (versus present), in lacking tubercles on the forelimbs (versus present), and in having a dorsal pattern of 11 dark-brown transverse irregularlyshaped dorsal bands or series of blotches (versus 7–10 relatively straight and largely unbroken brown bands bordered posteriorly by narrow to wide whitish margins). Cyrtodactylus manos sp. nov. also differs from the poorly known C. derongo Brown and Parker by the combination of smaller body size (maximum SVL 75 mm versus 112 mm), in having obvious ventrolateral folds (versus absent), in having ovoid enlarged femoral scales (versus subcircular), and in having a dorsal pattern in life of dark-brown transverse irregularly-shaped dorsal bands or series of blotches on a paler yellowish-brown ground colour (versus reddish-brown ground colouration with extensive small white blotches and maculations).

Cyrtodactylus manos sp. nov. differs from C. sermowaiensis De Rooij in its smaller size (maximum SVL 75 mm versus 112 mm), in lacking enlarged tubercles on the ventrolateral folds (versus present), in lacking tubercles on the forelimbs (versus present), in having a narrower head (HW/SVL 0.17 versus 0.18–0.20), in possessing enlarged ovoid femoral scales (versus no enlarged femoral scales), a dorsal pattern of 11 thin dark-brown transverse irregularly-shaped bands or series of blotches (versus 5–6 irregular dark-brown dorsal bands or series of blotches alternating with less extensive brown interstitial bands), and snout colouration in life dark-brown overlain by yellowish blotches (versus light greyish-brown overlain with dark-brown blotches); from C. arcanus Oliver, Richards & Sistrom in its lower number of dorsal tubercle rows (16–18 versus 22–25), absence (versus presence) of tubercles on the forelimbs, and in lacking transversely widened subcaudal scales (versus present); and from C. minor Oliver & Richards in its narrower head (0.17 versus 0.20–0.21), contrasting dark-brown mottling on back of head (versus at most very indistinct fine medium-brown reticulations or maculations), snout with yellow (or light brown in preservative) spots contrasting against a dark-brown background (versus plain mid-brown), and largest precloacal scales often triangular and> 10 rows anterior to cloaca (versus always circular and <10 rows anterior to cloaca) (Oliver & Richards 2012).

Cyrtodactylus manos sp. nov. differs from C. boreoclivus Oliver, Krey, Mumpuni & Richards and C. medioclivus Oliver, Richards & Sistrom by the combination of small size (maximum SVL 75 mm versus> 90 mm), nar- rower head (HW/SVL 0.17 versus 0.19–0.20), in lacking transversely enlarged subcaudal scales (versus present), in lacking enlarged tubercles on the ventrolateral folds (versus present), in lacking tubercles on the forelimbs (versus present) and in having a higher number of transverse bands of blotches on the dorsum (>5 versus <5); and from C. tanim Nielsen & Oliver by its smaller size (maximum SVL 75 mm versus> 90 mm), in lacking tubercles on the forelimbs (versus present), enlarged femoral scales ovoid and up to approximately double length of bordering scales (versus subcircular and always less than twice length of bordering scales), and dark-brown dorsal bands narrower and tending to be broken on posterior of dorsum (versus wider and generally unbroken for the length of the torso).

Cyrtodactylus manos sp. nov. occurs in close proximity to two similarly sized and patterned Cyrtodactylu s that are widespread in southern New Guinea. Of these, it differs from C. capreoloides Rösler, Richards & Günther in lacking enlarged tubercles along the ventrolateral folds (versus present), in having more ventral scales at midpoint of body (46 rows versus 31–39), and a higher number of brown bands or series of blotches extending from back of neck to cloaca (11 versus 5–6) ( Oliver et al. 2012a); and from C. papuensis Brongersma by its larger size (maximum SVL 75 mm versus 67 mm), in lacking enlarged tubercles on the ventrolateral folds (versus present), in lacking tubercles on the forelimbs (versus present), in having enlarged ovoid femoral scales (versus subcircular), and having yellow spots across the snout in life (versus absent) ( Rösler et al. 2007).

Genetic differentiation. Based on an alignment of the coding region of the mitochondrial ND2 gene Cyrtodactylus manos sp. nov. is genetically most similar to and may be the sister taxon to Cyrtodactylus arcanus from lower montane and hill forests in Madang and Jiwaka Provinces on the northern versant of New Guinea’s Central Cordillera. The divergence between these species is however relatively deep (mean Tamura-Nei genetic distances 0.227) and is estimated to have occurred over 10 million years ago ( Tallowin et al. 2018).

Etymology. The Greek manos can mean rare, sparse or thin (for example in the context of gases), we here use it in reference to the paucity of material for this species.

Distribution and ecology. Known only from 855 m a.s.l. in rugged karst country on Gobe Ridge, Southern Highlands Province, Papua New Guinea ( Fig. 3 ). This area receives extremely high annual rainfall, with significant precipitation normally occurring in each month ( McAlpine et al. 1983). The holotype was collected at night from ~ 2 m above the ground in a tree near the side of an infrastructure access road. The forest at the type locality is complex with small-crowned hill forest including Nothofagus trees on the upper slopes and ridges, and medium-crowned hill forest without Nothofagus on the lower slopes and gullies ( Fig. 4 ). Searching away from the road was limited by the challenging terrain, and no further specimens were observed during several nights of survey in the same area. No other geckos from the genus Cyrtodactylus species were observed at the collection site, however one specimen of Gehyra baliola was collected ( Oliver et al. 2010).

IUCN status. This species is known from a single specimen, so we recommend it be assessed as Data Deficient.

Figures

FIGURE 1. Holotype of Cyrtodactylus manos sp. nov. SAMA R62654 in life: A) whole body and B) head. Photographs by Stephen Richards.

FIGURE 2. Details of precloacal and female scales of holotype of Cyrtodactylus manos sp. nov. SAMA R62654. Enlarged ovoid femoral scale series apparent on left upper hindlimb. Scale = 2mm. Photograph courtesy Geoff Thompson, Queensland Museum.

FIGURE 3. Locality details for holotype of Cyrtodactylus manos sp. nov. and its putative sister taxon Cyrtodactylus arcanus.

FIGURE 4. Hill and lower montane forest on rugged karst ranges viewed from the type locality of Cyrtodactylus manos sp. nov. at Gobe Ridge, Papua New Guinea. Photograph by Stephen Richards.