Crenadactylus rostralis Storr, 1978

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 : 262-264

Crenadactylus rostralis Storr, 1978

South-west Kimberley clawless geckos Figs. 3 H, 4F, 16, 17

Crenadactylus ocellatus rostralis Storr, 1978 [‘Kimberley A’ of Oliver et al. (2010, 2012b)]

Holotype. WAM R32154, adult male, Geikie Gorge , Western Australia (18°07'S, 125°39'E), collected by W.H. Butler, April 1968. Fixed in 10% formalin, stored in 70% ethanol at WAM.

Paratypes (17). WAM R23058*, 43 km SE Halls Creek , WA (18°27'S, 127°15'E) ; WAM R26824–26, Napier Range, WA (17°20'S, 124°50'E); WAM R27388–92, Mount Anderson , WA (18°02'S, 123°56'E) ; WAM R46058– 59*, near Wolfe Creek Meteorite Crater , 122 km SW Halls Creek, WA (18°43'S, 126°45'E) ; WAM R46115*, 11 km E Margaret River Homestead , WA (18°38'S, 126°58'E) ; WAM R56841–45*, Lake Argyle , WA (16°15'S, 128°45'E) .

Some registration numbers presented in the original description are in error, with WAM R56441–45 associated with different species. The error originates from a minor numerical error in the registration numbers presented by Storr (1978), and underlined here. The correct numbers associated with the paratype specimens are WAM R56841– 45. Nine paratypes (marked with an asterisk) designated by Storr (1978) fall within the distribution of lineages associated with the C. naso complex identified by Oliver et al. (2012b), and are not true C. rostralis .

Diagnosis. A moderate-sized (to 32.7 mm SVL) species of Crenadactylus . Rostral not in contact with nostril, 2–3 internasals present, not extending beyond supranasal, postmentals granular, dorsal scales homogeneous and weakly keeled, 4–6 pre-cloacal pores, innermost pore-bearing scales in contact, no enlarged tubercles on original tails. Ground colour light greyish brown; dorsal pattern consists of well-defined pale and dark longitudinal stripes, lateral zone light grey with usually two moderate to well-defined dark lines between limbs, stippled with single pale scales; ventrum pale grey to white with moderate stippling forming longitudinal lines.

Description of holotype. WAM R32154, adult male with the following meristics (in mm): SVL 29.8; TailL 27.5 (original); HeadL 9.3; HeadW 4.6; HeadD 2.8; SnL 3.3; ILL 14.5; SupLab 9 (left), 9 (right); InfLab 9, 9; internasals 3.

A slender, small-bodied gecko; body elongate, oblong in cross section, ~1.5–2 times wider than deep; head narrow (HeadW/HeadL 0.50), elongate (HeadL/SVL 0.31), moderately depressed (HeadD/HeadL 0.30); in dorsal view, widest between eye and ear openings, narrower 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 3.3; SnL/HeadL 0.36), rounded tip; eye moderately large; rostral ~3 times wider than high, excluded from nostril contact by first supranasal, dorsal edge concave to accommodate first supranasal, slightly notched by median internasal, rostral groove originates from dorsal edge of scale below internasal, ~40% of rostral height; internasals 3, median internasal tiny; supranasals 2 per side; first oblong, transversely-oriented, ~2.0–2.5 times wider than high, in broad contact with nostril; second supranasal small, rounded, ~size of first supranasal; nostril small, ~1/3 size of first supranasal, directed dorso-laterally, in contact with both supranasals, 3 postnasals and first supralabial; postnasals 3, first and third ~half the size of first supranasal, second small, ~1/3 of first and third; supralabials 9 on both sides, antero-dorso edge of first supralabial in contact with nostril; second supralabial rectangular, wider than high, supralabials 3–5 smaller than first and second, all wider than high, sixth supralabial ~equal to first supralabial, supralabials 7–9 smaller than first two, gradually decreasing in size posteriorly; scales on crown small and granular, ~half the size of dorsal scales, becoming flattened and increasing in size anteriorly onto snout; scales on snout flat, enlarged, ~1.5–4.0 times the size of scales on crown; supraocular scales enlarged; 3 enlarged conical scales at postero-dorso edge of eye; mental trapezoidal, widest anteriorly, narrowing slightly to rounded posterior edge; gulars granular, ~1/3 to 1/4 the size of scales on ventrum; infralabials 9 on each side, first trapezoidal, slightly smaller than second, infralabials 2–4 square, gradually decreasing in size posteriorly, infralabials 5–9 rectangular, wider than high, gradually decreasing in height and width posteriorly.

Limbs short, distance between limbs nearly half of SVL (ILL/SVL 0.48), just over half of tail length (ILL/ TailL 0.52); scales on dorsal surface of forelimbs flat and rounded, imbricate, decreasing in size and becoming more granular distally; scales on ventral surface of forelimbs similar to dorsal; scales on dorsal surface of hind limbs rounded and slightly raised, imbricate, decreasing in size and becoming more granular distally; scales on ventral surface of hind limbs circular and slightly raised, increasing in size and becoming flatter and imbricate distally, granular on feet; fingers 5; toes 5; claws absent from all digits; digits moderately short; fourth finger lamellae 6 rows; fourth toe lamellae 8 rows; in dorsal view, enlarged scale between apical plates ~equal to 2 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 homogeneous, small, feebly keeled, juxtaposed, scales slightly raised with 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 1.5–2.0 times the size of dorsal scales in area, widest at midpoint, rounded posteriorly.

Tail original, nearly equal to SVL (TailL/SVL 0.92), tapers gradually from widest point posterior to vent to narrow rounded point; round in cross-section; scales homogeneous, imbricate and flat, variable in size and shape, ~3–4 times the size of scales on dorsum; ventral tail scales similar to dorsal tail scales, flattened and imbricate, ~1.5–3 times the size dorsal tail scales; single enlarged spur on both sides of cloaca, ~5–6 times the size of surrounding scales; pre-cloacal pores 6, forming a slight curve, median innermost pore-bearing scales in contact, pore-bearing scales notched on posterior edge to accommodate pore.

Coloration and pattern. In preservative, colour faded to light brown. A thin pale vertebral stripe 2–3 scales wide, bracketed by medium brown paravertebral stripes 3–4 scales wide; a light brown dorsolateral zone 6–8 scales wide, with several widely-spaced pale scales, continuing forwards through eye and onto snout as pale canthal stripe; dark brown dorsolateral stripes 3–4 scales wide, in contact with dorsal edge of hindlimb, continuing forwards to eye and onto snout as loreal stripe; light brown lateral zone below dark dorsolateral stripe, 3–4 scales wide; ventro-lateral stripe medium brown, weakly defined, 3–5 scales wide; crown and snout medium brown, bordered by light brown stripe (extension of dorsolateral zone); supralabials stippled with dark brown, continuing as weakly-defined dark brown stripe to arm; ventrum pale with 4 longitudinal stripes, outer pair darker, 2–3 scales wide, inner pair narrower, 1–2 scales wide; arms with dark variegations on dorsal surface, legs with weaklydefined dark brown longitudinal lines, ventral surfaces of limbs with irregular stippling; basal portion of tail (original) with dark brown stripes continuing from paravertebral and dorsolateral stripes on body, ventral portion of tail with 2 dark brown stripes.

Variation. Other specimens generally corresponded to the holotype specimen, with the following exceptions. The degree of keeling on the dorsal scales ranged from feebly keeled to smooth and rounded. Females lacked pre-cloacal pores and the spurs were smaller and less projecting.

Colouration and pattern. In life (based on recent photographs by PMO), background colour grey-brown with a series of alternating pale and dark alternating longitudinal stripes; pale grey vertebral stripe bordered by medium dark brown paravertebral stripes; pale to medium grey dorsolateral zone, continuing forwards through eye as pale canthal stripe; dark brown lateral stripe, continuing through eye on snout as poorly-defined loreal stripe; light grey ventrolateral zone with occasionally poorly-defined thin dark stripe near ventrolateral edge of body; top of head dark brown with some pale mottling; labials pale, stippled with dark brown. Dark brown paravertebral and lateral stripes usually with scattered pale scales. Lateral stripe usually darker than paravertebral stripes, but can also be of similar shade. Ventrolateral zone can be much paler than dorsolateral zone. Limbs dark brown with variable small pale spots; original tails continue dorsal pattern, regenerated tails with a mixture of pale and dark scales not forming conspicuous lines.

In preservative, pattern consists of alternating dark and light stripes. Silvery-grey vertebral stripe, narrow, 2–3 scales wide; medium grey-brown paravertebral stripes, bordered by dark brown edges, 6–7 scales wide; pale dorsolateral stripe, 4–5 scales wide, starts at postero-dorsal edge of eye, continues above limbs to tail; dark brown dorso-lateral stripe extends posteriorly from back of eye to top of hindlimb, anteriorly extends to top of ear opening; below dorsolateral line are two thin, ventro-lateral stripes; pale lateral zone divided by thin dark lateral stripe between limbs, forming pale line below dorsolateral that extends from angle of jaw across top of forelimbs and through hindlimb. Ventrum lightly stippled, one or two weakly defined brown lines towards outer edge of ventrum. Pale canthal and dark loreal stripes weakly defined, continuation of pale and dark dorsolateral stripes; top of eyes purplish; labials pale and heavily stippled with brown flecks; posterior edge of jaw heavily stippled, continuing as lateral line below ear opening to forelimb. Limbs dark, back of thigh has strong pale stripe, diffuse with small clusters of pale scales.

Distribution. Genotyped specimens were all collected from the Devonian Reefs Ranges in the south-western Kimberley region ( Fig. 2 ), extending from the Napier Ranges in the north-west to the Pillara Range on Gogo Station in the south-east. Additional (not genotyped) records of Crenadactylus from Mt Anderson in the south-west (~ 40 km from Derby) and from the south-east Kimberley are here considered to belong to C. rostralis pending genetic data to resolve their status ( Fig. 2 ). All samples formerly regarded as this species from elsewhere in the Kimberley are here considered part of the C. naso species complex.

Habitat. The few records with collection details all mention occurring in spinifex, including a number of recent samples that were raked from large clumps on and around limestone ranges (PMO, pers. obs.).

Etymology. The name rostralis is from the Latin rostrum, meaning beak or snout, in reference to this species’ distinctive configuration of having the rostral scale separated from the nostril.

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.)