Crenadactylus pilbarensis, Doughty, Paul, Ellis, Ryan J. & Oliver, Paul M., 2016

Doughty, Paul, Ellis, Ryan J. & Oliver, Paul M., 2016, Many things come in small packages: Revision of the clawless geckos (Crenadactylus: Diplodactylidae) of Australia, Zootaxa 4168 (2), pp. 239-278 : 259-261

Crenadactylus pilbarensis sp. nov.

Pilbara clawless geckos

Figs. 3 F, 4E, 14, 15

[‘Pilbara’ of Oliver et al. (2010)]

Holotype. WAM R132630, adult female, Burrup Peninsula , Western Australia (20°35'34"S, 116°47'58"E), collected by B. Maryan, 31 May 1998. Fixed in 10% formalin, stored in 70% ethanol at WAM . Liver sample stored at the Evolutionary Biology Unit , South Australian Museum, Adelaide ( SAMA) .

Paratypes (6). WAM R 100988, 80 km south of Telfer , WA (22°20'S, 122°05'E) ; WAM R132540, Burrup Peninsula, WA (20°36'45"S, 116°47'37"E); WAM R132627, WAM R132629, Burrup Peninsula, WA (20°35'34"S, 116°47'58"E); WAM R 140394, Deepdale Outstation , Robe River Station, WA (21°43'S, 116°11'E) WAM R160059, 55 km east-south-east of Meentheena Outcamp, WA (21°19'19"S, 121°00'08"E) .

Diagnosis. A small (to 28.4 mm SVL) species of Crenadactylus . Rostral in full contact with nostril, internasal (if present) not extending beyond supranasal, single greatly enlarged postmental, dorsal scales homogeneous and moderately keeled, 6 pre-cloacal pores in males with innermost pore-bearing scales in contact, no enlarged tubercles on original tails. Ground colour light brown; dorsal pattern consists of well-defined pale and dark longitudinal stripes, scattered clusters of 1–3 pale scales, lateral zones light grey to tan with stippling occasionally forming 1 or 2 broken or weakly defined lateral lines; ventrum pale off-white with weak to moderate stippling.

Description of holotype. WAM R132630, adult female with the following meristics (mm): SVL 27.0 mm; TailL 24.3 mm (partially regenerated); HeadL 8.4; HeadW 4.1; HeadD 2.5; SnL 3.3; ILL 13.0; SupLab 8 (left), 9 (right); InfLab 8, 9; internasals 1; PCP 0.

A slender, small-bodied gecko; body elongate, oblong in cross section, ~1.5–2.0 times wider than deep; head narrow (HeadW/HeadL 0.49), elongate (HeadL/SVL 0.31), moderately depressed (HeadD/HeadL 0.30); in dorsal view, widest at ear openings, not wider than widest portion of body; head not distinct from neck, neck very weakly constricted; loreal region weakly convex, concave around nasal region; snout elongate (SnL 3.3; SnL/HeadL 0.39), rounded tip; eye moderately large; rostral ~3 times wider than high, in broad contact with nostril, slightly scalloped dorsally to accommodate first supranasal, notched by internasal, rostral groove originates from dorsal edge of scale, ~40% of rostral height; internasal tiny, ~one-fifth the size of first supranasal in area; supranasals 2 per side; first supranasal oblong, transversely oriented, ~2 times wider than high, in broad contact with nostril; second (dorsal) supranasal small, rounded, tapering to blunt point at nostril contact, ~half the size of first supranasal; nostrils small, ~one-third size of first supranasal, directed dorsolaterally, in contact with rostral, first and second supranasals, postnasals, and first supralabial; postnasals 2, equal to size of second supranasal; supralabials 8 on both sides, antero-dorso edge of first supralabial in contact with nostril; second supralabial rectangular, wider than high, length equal to length of first supralabial, supralabials 3–8 smaller than first and second, gradually decreasing in size, all wider than high; scales on crown small and flattened, ~one-third the size of dorsal scales, increasing in size anteriorly onto snout; scales on snout flat, enlarged, ~2–3 times the size of scales on crown; supraocular scales enlarged; single enlarged conical scale at postero-dorso edge of eye; mental trapezoid-shaped, widest anteriorly, narrowing slightly to concave posterior edge, terminates equal to ventral edge of first infralabials; single enlarged postmental, hexagonal in shape, ~2 times area of scales posterior and lateral to enlarged postmental, ~4 times larger than other gular scales; gulars granular, rounded, ~0.25–0.50 the size of scales on ventrum; infralabials 9 on each side, first largest, square-shaped, gradually decreasing in height and width posteriorly, infralabials 1–3 square or rectangular, 4–9 rectangular, wider than high.

Limbs short, distance between limbs nearly half of SVL (ILL/SVL 0.48), slightly over half the length of tail (ILL/TailL 0.54); scales on dorsal surface of forelimbs imbricate, flattened and rounded, decreasing in size distally; scales on ventral surface of forelimbs similar to dorsal; scales on dorsal surface of hind limbs rounded and slightly raised, decreasing in size and becoming more rounded distally; scales on ventral surface of hindlimbs flat and circular, slightly larger in area than dorsal hindlimb scales; fingers 5; toes 5; claws absent from all digits; digits moderately long; fourth finger lamellae in 6 rows; fourth toe lamellae in 8 rows; in dorsal view, enlarged scale between apical plates 1.5 times the size of adjacent lateral scales; apical plates much wider than digit; two pairs of dorsal apical plates; one pair of ventral apical plates, circular.

Scales on dorsum small and homogeneous, round to oblong, juxtaposed; scales slightly raised, moderately keeled, highest point at posterior edge of scale, widest at midpoint of scale, becoming flatter and imbricate laterally; scales on ventrum homogeneous, flat, imbricate, equal to 1.5 times the size of dorsal scales in area, widest at midpoint, tapering to a rounded or flattened posterior edge.

Tail partially regenerated, last 40% of tail regenerated, slightly shorter than SVL (TailL/SVL 0.90), tapers gradually from widest point posterior to vent, more abruptly in posterior quarter of tail; round in cross-section; scales homogeneous, imbricate and flat, square to oblong in shape; subcaudal scales flattened, ~1.5–2 times the size of dorsal tail scales; single enlarged spur on both sides of cloaca, ~3–4 times the size of surrounding scales.

Colouration and pattern. In preservative, pattern comprised of alternating light and dark longitudinal stripes on dorsum and sides; light brown-tan vertebral stripe narrow, 2–4 scales wide, scales lightly stippled with darker brown, originating on back of head, extending length of body, terminates at base of tail where paravertebral stripes merge; paravertebral stripes wider than vertebral, 3–5 scales wide, medium brown, originating from postero-dorsal edge of eye, curving around posterior of head to vertebral stripe, continuing parallel with vertebral stripe for length of body, tapering from hindlimbs to merge and form single broken line on tail; light brown-tan dorso-lateral stripe 3–4 scales wide, extends from postero-dorsal edge of eye, above forelimbs, parallel with vertebral stripe for length of body, over hindlimbs and onto tail, faded and broken on tail; dorsolateral stripe narrow, 3–4 scales wide, ~equal width to paravertebral stripe, dark brown, same as paravertebral, extends from posterior edge of eye above ear opening, above forelimbs along length of body, above hindlimbs and onto tail, ~one-half of tail length; pale lateral zone below dorsolateral stripe with narrow, solid, dark brown lateral stripe between limbs, 2–3 scales wide; weak stripe below lateral stripe on ventro-lateral edge, extending anteriorly from forelimb to ventral edge of ear opening; ventrum pale, heavily stippled with brown flecks; dark triangular patch on snout, crown a mixture of light and dark scales, dark-edged by extension of paravertebral stripes to eyes, top of eyes purplish, dark brown scales below eye on orbit; labials pale, heavily stippled with brown flecks; pale canthal stripe, extension of pale dorsolateral stripe from eye to rostral scale, below a dark loreal stripe, extension of dark dorsolateral stripe; dorsal surface of limbs with mixed pale, light brown and dark brown scales, scattered clusters of pale scales resulting in some spotting, extending onto digits; dorsal stripes (with exception of vertebral) continue to tail but broken up.

Variation. Most specimens conformed to the holotype, with some of the following exceptions. Males possessed 6 pre-cloacal pores (one individual with 4) in a continuous row. Pores formed by a notch in the posterior edge of scale. Females lacked pre-cloacal pores. In males the cloacal spurs are larger than those of females and protrude further than for females. Regrown tails tended to be paler with smaller scales compared to the tail of the holotype.

The diagnostic character of a greatly enlarged postmental was unambiguous in all specimens examined, although the shape tended to vary from round to oblong ( Fig. 3 F). Keeling on the dorsal scales also varied from weak keels to moderately strong.

Colouration and pattern. In life, light to dark brown ground colour with contrasting dark and pale longitudinal stripes. In preservative, thin vertebral stripe pale tan-grey, paravertebral stripes to either side emanating from top of eye and joining just before base of tail; pale dorsolateral stripe from antero-dorso portion of eye to tail, continuing anteriorly from eye as pale canthal stripe; dark brown triangular patch on snout continuous with dark brown crown, intermixed with paler scales; dark dorsolateral stripe from ventro-dorso portion of eye to above limbs to tail, anterior to eye forming dark loreal stripes; labials pale, heavily stippled with dark brown; lateral surfaces pale with thin dark brown stripes, uppermost more defined, lower lateral stripe can be extensively broken and indistinct; stippling on pale ventrum variable; limbs a mixture of dark and light brown scales with small clusters of pale scales apparent; regenerated tails a mixture of dark and pale brown scales, forming short lines or showing no pattern.

Distribution. Restricted to the Pilbara region of Western Australia ( Fig. 2 ). Most records are from the Pilbara craton, although many specimens have also been collected from the Burrup Peninsula. Absent from offshore islands except Dolphin Island that is separated from the Burrup Peninsula by a channel only several hundred metres wide. Northern records are from Shay Gap and Meentheena Conservation Reserve. The southern-most records are from the Barlee Range in the south-west and Kumarina in the south-east. Outlying records to the east are from Karlamilyi (Rudall River) National Park and Jiggalong.

Habitat. Collection records indicate this species occurs in spinifex clumps on rocky hills and in gullies on the mainland, but sandy substrates for the Dolphin Island specimens.

Etymology. Named for the Pilbara region where this species occurs.

Figures

FIGURE 2. Distribution of the Crenadactylus ocellatus species-group including new species described in this paper. Darker shades denote areas of high topographic complexity, lighter shades lower complexity. Colours for taxa match those in Fig. 1. Questionable type location of Ebenavia horni holotype indicated by ‘? ’.

FIGURE 3. Morphological variation within the Crenadactylus ocellatus species group (left to right, top to bottom): A) typical homogeneous dorsal scalation of Crenadactylus species (except C. tuberculatus), B) heterogeneous dorsal scalation of C. tuberculatus sp. nov. with enlarged tubercles, C) typical internasal configuration of Crenadactylus species (except C. horni) showing small internasal when present (upper left) or supranasals in contact (lower right), D) internasal configuration of C. horni showing enlarged internasal extending beyond posterior edge of supranasals, E) typical postmental configuration of Crenadactylus species (except C. pilbarensis) showing granular gular scales, F) postmental configuration of C. pilbarensis sp. nov. showing enlarged postmental, G) typical snout scalation in lateral view (exception C. rostralis, C. naso [part]) showing rostral-nostril contact, H) snout scalation in lateral view of C. rostralis (and C. naso [part]) showing excluded rostral contact with nostril. (Drawings: A, B – K. Aplin; C – F, R. J. Ellis; G, H – R. E. Johnstone.)