Gehyra girloorloo, Oliver, Paul M., Bourke, Gayleen, Pratt, Renae C., Doughty, Paul & Moritz, Craig, 2016

Oliver, Paul M., Bourke, Gayleen, Pratt, Renae C., Doughty, Paul & Moritz, Craig, 2016, Systematics of small Gehyra (Squamata: Gekkonidae) of the southern Kimberley, Western Australia: redescription of G. kimberleyi Börner & Schüttler, 1983 and description of a new restricted range species, Zootaxa 4107 (1), pp. 49-64 : 56-61

Gehyra girloorloo sp. nov.

Kimberley Karst gecko Figs. 4–7

Holotype. WAM R175045 (field number CCM 3257) (male), Gogo Station, Pillara Range, south entrance of Menyous Gap (18.40439°S; 125.83698°E), collected on 4 November 2014 by P.M. Oliver, G. Armstrong and P. Skipwith.

Paratypes. WAM R113727 (female), Cadjbut Mine 90 km south-east Fitzroy Crossing (18.7500°S; 126.1500°E); NMV D77029 and NMV D77030 (females), and NMV D77031 and NMV D77032 (males), Ngumpan Cliff area (18.75625°S; 126.06474°E); WAM R175037 (PMO147) and WAM R175038 (PMO149) (males), <1 km south of Galeru Gorge (18.61407°S; 126.08386°E); WAM R175039 ( CCM 3242) and WAM R175040 ( CCM 3243) (males), Gogo Station, Limestone Billy Hills (18.32724°S; 125.76498°E); WAM R175043 ( CCM 3246) (female), Gogo Station, Limestone Billy Hills (18.33516°S; 125.75244°E).

Diagnosis. Digits broadly expanded basally and subdigital scansors present on all digits of manus and pes. Digit I of manus and pes clawless, penultimate phalanx of digits II–V free from scansorial pad. Differs from non- Australian Gehyra by the combination of: absence of webbing between third and fourth toes, absence of a skin fold along the posterior hindlimb and small adult size (SVL <48 mm). Differs from all other Australian Gehyra by the combination of small body size (SVL <48 mm), divided subdigital lamellae without basal wedge of granules, short snout and large eyes (OrbL/SnEye 0.58, 0.51–0.72), low number of pre-cloacal pores in males (8–11), postmentals not in contact (at most in point contact) with the second supralabial, one pair of outer chin shields and pinkishbrown dorsal background colour with pattern consisting of alternating bands of indistinct off-white spots and darkbrown transverse blotches on heavily stippled background.

Description of holotype. Adult male with following dimensions (in mm): SVL 41.3, HD 4.7, HL 10.2, HW 8.2, HindL 5.4, ArmL 5.0, TrunkL 18.4, NarEye 3.2, SnEye 4.5, InterN 1.5, InterO 3.2, OrbL 2.4, RosW 1.5, RosH 0.9. Summary meristic data are as follows: SupLab 8; InfLab 7; InterNSc 0; PreCloacal 9; FingSubDL 6; ToeSubDL 7.

A small (41.3 mm SVL), slender gecko ( Fig. 5 ). Head slightly depressed (HD/HL 0.46), moderately wide (HW/HL 0.80), of similar width to midbody, widest at posterior edge of jaw, tapering to snout, narrows posteriorly to a moderately constricted neck. Snout short (SnEye/HL 0.44), less than twice eye length (OrbL/SnEye 0.54), rounded in dorsal profile, slightly convex from mid-eye to naris when viewed laterally in profile. Eyes moderately sized (OrbL/HL 0.24), pupil vertical. Ear openings small and circular. Nostrils rounded, contacted by rostral, supranasal, two postnasals and first supralabial; second (ventral) postnasal ~2 times larger than first (dorsal), supranasals in contact, no internarial scale. Rostral scale rectangular with nearly flat dorsal edge, wider than high, 1.5 mm wide, 0.9 mm high (RosH/RosW 0.58), deeply furrowed, rostral crease extending from dorsal edge ~40% of rostral height. Supralabials 8, infralabials 7. Scales on snout large, up to 3 times larger than scales on crown of head and body, imbricate and slightly projecting along posterior edge; fold of skin across snout from eye to eye (artefact of preservation). A row of slightly enlarged scales above supralabials gradually decrease in size posteriorly. Mental scale triangular, divides postmentals ~35%; postmentals narrowly separated from second infralabial on right side, in point contact on left side; single pair of outer chin shields with curved dorso-postero edge, ~two-thirds the height of postmentals and ~30–40% smaller in area; outer chin shield in point contact with first infralabial on right side, narrowly in contact on left.

Body long (TrunkL/SVL 0.46) and slender, slightly depressed and with a weak ventro-lateral fold posterior to axilla. Dorsal midbody scales small and granular, relatively homogenous, conical, juxtaposed; lateral scales slightly larger, more projecting and heterogeneous than those on dorsal surface, slightly imbricate; ventral scales ~3 times larger than dorsal scales, flat, diamond-shaped with rounded edges, juxtaposed. Pre-cloacal pores in a series of 9, forming a short continuous chevron with apex orientated anteriorly; pores centred in scales, innermost scales the largest. Two enlarged, rounded and protruding cloacal spurs present on either side of cloaca.

Limbs short (ArmL/SVL 0.12; HindL/SVL 0.13); dorsal and ventral scales generally small, rounded and juxtaposed; scales on anterior edge of limbs slightly larger and imbricate. Fingers and toes 5; expanded toe pads oval; distal row of dorsal scales on toe pads elongate and sharply pointed, forming a serrated ‘fringe’. Claws long and free, present on digits 2–5, arising from dorsal surface of expanded toe pads and extending above and beyond toe pad, subdigital lamellae divided, 6 pairs on fourth finger, 7 pairs on fourth toe, all pairs of lamellae in contact, apical lamellae undivided and wedge-shaped.

Most of tail is original (52.0 mm, TailL/SVL 1.3), very thin, tapering gently to fine tip, slightly dorso-ventrally flattened at base, proximal 31 mm section original, distal 21 mm section regrown. At widest part near base— 4.3 mm wide, 3.3 mm deep. Dorsal caudal scales small, granular and relatively homogeneous, subcaudal scales in a single large transversely widened series.

Colouration of holotype (in preservative). Background colour pale grey, lightly stippled with darker gray, a series of pale circular spots tending to form oblique transverse rows, enclosed by more extensive transverselyoriented darker grey markings or larger variegations; crown of head with small pale spots above tympanum region, snout and sides of head dark grey, no streaks emanating posteriorly from eye, labials heavily stippled; limbs as for dorsum with smaller pale spots; undersurfaces pale off-white; dorsal surface of tail encircled by pale (wider) and dark brown (thinner) bands.

Variation. Table 1 presents ranges of variation for the characters measured. In a small number of specimens, the postmental and second infralabial are in point contact, otherwise they are separated. The same pattern holds for internasals—in most specimens the supranasals are in broad contact above the rostral, in a small number a tiny internasal scale is present.

Colouration in preservative is as follows: background dorsal colour pale tan or grey ( Fig. 6 ), densely stippled with fine blackish-brown variegations, moderate sized (0.5 – 1.5 mm wide) poorly defined pale circular to oval spots scattered on the dorsum, separated by concentrated patches of dark-brown markings that coalesce to form weakly defined transverse bands; density and distribution of dorsal pattern elements varies along body: usually little or no clear pattern on anterior portion of head, more clearly defined on nape with scattered small light spots and indistinct dark blotches, and consisting of alternating series of comparatively large and more well defined pale spots and indistinctly defined transverse brown bands on the torso and original tail. Limbs as for torso, with scattered distinct to indistinct small pale spots; undersurfaces largely unpigmented, but with dense fine dark brown maculations around the ventrolateral regions of head, limbs and ventral tail scales. Regrown tail light greyishbrown with diffuse longitudinally aligned narrow dark streaks.

Colouration in life. The following notes are based on photographs of specimens NMV D77030 and WAM R175037 shown in Fig. 7 and WAM R175042–3 (not shown). Dorsal surfaces pale purplish buff very finely stippled with medium brown, overlain on dorsum and tail with alternating transverse series of pale spots lacking borders and irregular dark-brown blotches that tend to be transversely aligned and intermittently bordered with yellow-orange. Head with smaller pale and dark spots with scattered yellow-orange flecks or fine spots. Regenerated tails often have a distinctive yellowish wash and very fine brown longitudinal markings. Iris dark golden brown with fine black reticulations.

Habitat and reproduction. This species is closely associated with dissected limestone outcrops, and also occurs on small trees and shrubs ( Fig. 8 ). It tends to be less common on exposed vertical rock faces than its much larger sympatric congener G. ko i r a Horner. The locally occuring form of Gehyra nana tends to utilise different habitats—it is rarely found on limestone and generally on smaller boulders and rocky debris in surrounding areas. Gehyra girloorloo sp. nov. can be abundant in its preferred habitat, for example, most large shrubs along an open rock face in Menyous Gap had at least one specimen, often positioned head down close to the ground in what appeared to be a hunting posture. In contrast, we found this species to be scarce in early July 2014 when temperatures were low (<15°C), with only two specimens observed over two nights of searching around Mt Piere Station.

Like all Gehyra in the variegata-punctata species-group, this species lays a single egg. Some females were gravid in November in spring at the end of the dry season.

Distribution. Gehyra girloorloo sp. nov. is only known from a small area of limestone outcropping in the King Leopold Range of the south-west Kimberley on Gogo and Mt Piere Stations ( Fig. 1 ). Known localities extend in a narrow band from the limestone Billy Hills in the north-west, to just north-west of Ngumpan Cliff in the southeast, a straight line distance of approximately 55 km.

Etymology. Girloorloo , pronounced “gir-loor-loo”, is a word the local Gooniyandi mob use for the limestone this species appears to be restricted to. This species name was suggested by elders from the Gooniyandi mob who speak for country on which this species occurs.

Comparisons. Gehyra girloorloo sp. nov. can be distinguished from all non-Australian Gehyra by the absence of webbing between third and fourth toes (versus present), the absence of a skin fold along the posterior hindlimb (versus present) and its generally smaller size (max SVL <50 mm versus> 50 mm).

Within Australia, G. girloorloo sp. nov. can be distinguished from all members of the G. australis speciesgroup (which are largely restricted to northern Australia) by its smaller size (max SVL <50 mm versus> 50 mm), divided subdigital lamellae (versus at least some undivided), lower number of pores in the males (<12 versus> 12) and females laying just one egg per clutch.

Gehyra girloorloo sp. nov. can be distinguished from members of the G. variegata group from the Australian arid zone by its lower number of pre-cloacal pores in males (<12 [mode 9] versus usually more than 10 [ Hutchinson et al. 2014]), no conspicuous dark streaks emanating from behind the eyes, at most only light red hues (versus rich reddish-brown) and less contrasting dorsal pattern combining diffuse dark markings (versus extensive reticulations) and diffuse light spots (versus tending towards smaller and well defined). A further species in this group, G. pilbara , is similarly small, but differs in dorsal colouration (reddish-brown vs. pinkish-grey), the presence of obviously enlarged loreal scales above the infralabials (versus absent) and in having an extremely short snout resulting in short, wide postmentals (versus tall and thin in G. girloorloo sp. nov.) ( Fig 4 .).

Gehyra girloorloo sp. nov. can be distinguished from most other members of the G. variegata group that also occur in the AMT as follows: from G. xenopus and G. spheniscus by the absence of a wedge of granules between proximal lamellae (versus present), and in the case of the former species, also much smaller size (max SVL 48 versus 79 mm); from G. occidentalis by its lower number of subdigital lamellae (5–7 versus 7–10) and small body size (max SVL 48 mm versus 76 mm); and from G. multiporosa by the absence of dark lateral head streaks, and fewer pores in males (8–11 versus 20–49).

A final taxon from this region, G. nana , is a complex of species (unpublished data). However, G. girloorloo sp. nov. can be distinguished from both geographically proximate and type G. nana by its pinkish-grey dorsal colouration (versus reddish), background stippled (versus plain), larger and more diffuse pale spots (versus small and clearly defined), diffuse and transversely-oriented dark brown blotches on dorsum (versus clearly defined brown blotches or [usually] spots), and low number of pre-cloacal pores in males (8–11 versus 11–17). Gehyra nana from around localities from where G. girloorloo sp. nov. has been recorded are also particularly small (SVL 39.0, 35.0– 41.9 mm) and strongly spotted (see Fig. 5 ).

Figures

FIGURE 1. Distribution of Gehyra kimberleyi (circles) and G. girloorloo sp. nov. (diamonds) from the Kimberley and surrounding regions of Western Australia; lighter regions are higher in elevation.

FIGURE 4. Chin shield configuration in Gehyra treated here; A) G. kimberleyi WAMR 175035, B) G. pilbara WAMR 108632, C) G. girlooloo sp. nov. WAMR 175045 and D) G. nana WAMR 175063. Scale bar = 1 mm.

FIGURE 5. Dorsal and ventral views of the Gehyra girloorloo sp. nov. holotype (WAM R 175045, CCM 3257). Scale bar = 1 cm.

FIGURE 6. Small saxicoline Gehyra of the southern Kimberley, Western Australia. Top: G. girloorloo sp. nov. NMV D 77030 near Ngumpan Cliff; middle: G. girloorloo sp. nov. WAM R 175037 (PMO 147), Galeru Gorge; bottom: G. nana NMV D 77035 near Ngumpan Cliff (photographs—P. Horner and T. Parkin).

FIGURE 7. Gehyra girloorloo sp. nov. paratypes showing variation in colour and pattern (in preservative). Scale bar = 1 cm.

FIGURE 8. Habitat of Gehyra kimberleyi (small trees in foreground) and G. girloorloo sp. nov. (karstic limestone in background) at Gogo Station, Western Australia (photograph—P. M. Oliver).