Crenadactylus tuberculatus, 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 : 256-259

Crenadactylus tuberculatus sp. nov.

Cape Range clawless geckos Figs. 3 B, 4D, 12, 13

[‘Cape Range’ of Oliver et al. (2010)]

Holotype. WAM R174304, adult male, Charles Knife Road , Cape Range National Park, North West Cape, Western Australia (22°05'26.48"S, 114°00'39.57"E) by P. Doughty, A.M. Bauer and R.J. Ellis, 19 August 2014. Fixed in 10% formalin, stored in 70% ethanol at WAM . Liver sample stored in 100% ethanol at WAM.

Paratypes (6). WAM R61203, Yardie Creek , WA (22°20'S, 113°49'E) ; WAM R134295, WAM R134627, WAM R134945, 1.5 km SW Vlamingh Head lighthouse, North West Cape , WA (21°48'30"S, 114°06'07"E) ; WAM R132481, WAM R132483, Shothole Canyon , Cape Range National Park, WA (22°03'S, 114°01'E) .

Diagnosis. A very small (to 27.7 mm SVL) species of Crenadactylus with long (HL/SVL 0.30–0.35) and narrow (HW/HL 0.43–0.50) head. Rostral in full contact with nostril, internasal (if present) not extending beyond supranasal, 2 small postmentals, dorsal scales heterogeneous with scattered enlarged keeled tubercles, males with 4 pre-cloacal pores with innermost pore-bearing scales separated by a small intervening scale, no enlarged tubercles on original tails. Ground colour light to dark greyish-brown, dorsal pattern consists of weakly-contrasting pale and dark longitudinal stripes, small pale spots may be present in dorsolateral zone, lateral zones grey with at most faint uniform stippling (not forming irregular lines), ventrum pale off-white with stippling absent to weak.

Description of holotype. WAM R174304, an adult male with the following meristics (in mm): SVL 24.8; TailL 11.3 (original); HeadL 7.9; HeadW 3.9; HeadD 2.3; SnL 2.2; ILL 11.2; SupLab 8 (left), 8 (right); InfLab 9, 9; internasals 1; PCP 4.

Slender, small-bodied with elongate body, round to oblong in cross section, ~1.5 times wider than deep; head narrow (HeadW/HeadL 0.49), elongate (HeadL/SVL 0.32), moderately depressed (HeadD/HeadL 0.29); in dorsal view, widest just posterior to eye, slightly wider than widest portion of body; head not distinct from neck, neck weakly constricted; loreal region weakly convex, weakly concave around nasal region; snout elongate (SnL 2.2; SnL/HeadL 0.40), round tip; eye moderately large; rostral ~3 times wider than high, in broad contact with nostril, dorsal edge concave to accommodate first supranasal, rostral groove ~60% of rostral length from dorsal edge below internasal notch; internasal tiny, ~one-fifth the size of first supranasal in area; supranasals two per side; first supranasal (in contact with rostral) oblong, transversely oriented, ~2.5 times wider than high, in broad contact with nostril; second (upper) supranasal small, rounded, ~one-third the size of first supranasal; nostril small, ~one-third size of first supranasal, directed dorsolaterally, in contact with rostral, first and second supranasals, three postnasals, and first supralabial; postnasals 3; supralabials 8 on both sides; antero-dorso edge of first supralabial in contact with nostril, postero-dorso edge notched by third postnasal and first loreal; 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, ~equal to size of smaller dorsal scales, ~one-sixth the size of enlarged dorsal tubercles, increasing in size anteriorly onto snout; scales on snout flat, enlarged, ~1.5–2.0 times the size of scales on crown; supraocular scales enlarged; two enlarged conical scales at postero-dorso edge of eye; mental trapezoid-shaped, widest anteriorly, narrowing slightly to posterior edge, terminates just beyond ventral edge of first infralabials; postmentals two, round in shape, ~equal to size of scales posterior to postmental; gulars granular, rounded; infralabials 9 on each side, first largest, square-shaped, gradually decreasing in height and width posteriorly, 1–3 square, 4–9 rectangular, wider than tall.

Limbs short, distance between limbs nearly half of SVL (ILL/SVL 0.45), nearly equal to tail length (ILL/TailL 0.99); scales on dorsal surface of forelimbs 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 flattened and more rounded distally; scales on ventral surface of hind limbs flat and circular, imbricate, increasing in size distally; 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 ~2 times the size of adjacent lateral scales; apical plates much wider than digit; one pair of ventral apical plates, circular, as wide as long.

Scales on dorsum heterogeneous: background of small homogeneous scales with scattered enlarged scales with prominent keeling; small dorsal scales homogeneous, slightly raised; enlarged tubercles scattered on dorsum and nuchal region, loosely aligned longitudinally, ~4–6 times the size of surrounding smaller scales in diameter, separated from one another by 1–4 smaller scales, enlarged tubercles have raised midline forming a moderate keel, tallest at posterior edge of scale; some enlarged tubercles in dorso-lateral zone, absent on lateral surfaces; scales on ventrum homogeneous, rounded and flattened, ~2 times the size of smaller scales present on dorsum, all similar in size and shape.

Tail original, nearly half of SVL (TailL/SVL 0.45), tapers gradually from widest point posterior to vent to narrow rounded point; round in cross-section; dorsal scales somewhat rounded and imbricate, variable in size and shape, ~0.25–0.75 the size of enlarged tubercles on dorsum; ventral tail scales similar to those of dorsal tail scales but more flattened; single enlarged post-cloacal spur on both sides of cloaca, ~6 times the size of surrounding scales; pre-cloacal pores 4, forming a partial chevron, pore-bearing scales notched on posterior edge to accommodate pore, two pores on each side separated by a single intervening poreless scale.

Colouration and pattern. In life, ground colour light brownish-grey with moderately-contrasting dark brown longitudinal stripes, all stripes with some intermingling of dark and pale scales, some hints of orange on enlarged tubercles. Dark paravertebral stripes enclose a narrow pale vertebral stripe from the crown to posterior to hindlimbs where the paravertebral stripes join; pale dorsolateral stripe from posterior edge of eye to tail, small widely-spaced clusters of orange-tinted enlarged tubercles above hindlimbs and before tail, stripe continuing forwards anterior to eye as pale canthal stripe; above pale canthal stripe a dark triangular patch on snout; crown with a mixture of dark brown and black scales; dark brown dorsolateral stripe from posterior edge of eye to tail, continuing forwards on snout as dark loreal stripe; labial scales pale with dark mottling; lateral surfaces light brown with dark variegations suggesting a lateral line; limbs a mixture of light and dark brown scales with peppering of black scales occasionally forming short lines; ventrum pale off-white with dark stippling on underside of limbs, lower abdomen and between arms, elsewhere lightly stippled; original (see below) tail light to medium brown with scattered black scales. In preservative, colours faded but all stripes discernible.

Variation. Most specimens examined conformed to the holotype, with the following exceptions. Enlarged dorsal tubercles tended to not occur anterior to the ear openings, but in some individuals they occurred up to the level of the eyes, especially behind the eyes. Most individuals lacked tails (original or regrown), and we believe the holotype tail is an original based on the scalation and darker colouration compared to regenerated tails in our limited sample. Regrown tails tended to be paler with smaller scales compared to the holotype tail. WAM R134627, a male, has an atypical pattern of three pre-cloacal pores in a single row, but the scales in this area were irregularly-shaped. Females differed from males in that they lacked pre-cloacal pores and the cloacal spurs tended to not protrude laterally as much as those of males.

Colouration and pattern. Of the few individuals photographed in life, most of the variation is in shade—from light tan or brown to dark greyish brown. Other variable features are the small clusters of orange-tinted scales within the pale dorsolateral stripe near the legs and base of tail, ranging from absent to conspicuous. Occasionally the upper lateral zone has a dark edge that forms a weakly-defined additional thin lateral stripe, continuing anteriorly from forelimb to ear opening. In contrast to the holotype, the pale spots on the limbs are more conspicuous in most other individuals.

Distribution. Restricted to the Cape Range of the North West Cape on the Western Australian coast near Exmouth ( Fig. 2 ). The southernmost records are from Yardie Creek, where it is sympatric with C. occidentalis sp. nov. ( Fig. 2 ). Several records are from Charles Knife Road and Shothole Canyon, with additional records from near Vlamingh Head and the lighthouse at the northern end of the Cape Range. All save one record are from within the boundaries of the Cape Range National Park.

Habitat. Most habitat notes indicate collection from living or dead spinifex clumps, and usually in limestone gorges but with some records from coastal dunes. One specimen was collected from a dead log (WAM R88600). The holotype was collected from the upper edge of a rocky gorge with scattered shrubs and spinifex. Etymology. The species name tuberculatus (Latin) is in reference to the enlarged tubercles on the dorsum of this species, unique within Crenadactylus .

Remarks. No other Crenadactylus has heterogeneous dorsal scales as observed in C. tuberculatus sp. nov. ( Fig. 3 B). The function of these scales is unknown. This species is also Australia’s smallest gecko species (maximum SVL <28 mm).

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.)