Gehyra einasleighensis Bourke, Pratt, Vanderduys & Moritz, 2017, sp. nov.

Gehyra einasleighensis sp. nov.

Einasleigh rock dtella Figs. 3–5

Holotype. QM J94587 (field number CCM0092) (male), Cobbold Gorge camp (18.79611°S; 143.42386°E); collected on 18 April 2013, by C. Moritz, E. Vanderduys and R. Agudo.

Paratypes. Australia: Queensland: QM J94588 (field number CCM 0105) (female), Whitewater Station, Undara (18.14897°S; 144.57213°E), QM J94589 (field number CCM 5118) (male), 9 km west of Georgetown (18.28926°S; 143.46529°E), QM J94591 (field number CCM 5128) (male), East of Croydon (18.23171°S; 142.4129°E), QM J94595 (field number CCM 5186) (female), 34 km E of Georgetown (18.27407°S; 143.83688°E), QM J94597 (field number CCM 5196) (male), north of Forsayth (18.5667°S; 143.56871°E), QM J94598 (field number CCM 5213) (male), 6.6 km SE of Petford (17.37989°S; 144.96419°E).

Diagnosis. Digits broadly expanded basally and subdigital lamellae 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 very small adult size (SVL <41 mm). Differs from all other Australian Gehyra by the combination of small body size (SVL <41 mm), small number (± 6) of divided subdigital lamellae, postmentals contacting both first and part of second infralabials, one pair of outer chin shields, supranasal scales in broad contact, usually no internasal scale, and mid tan to golden dorsal background colour with pattern consisting of scattered pale ocelli and irregular dark-brown blotches on stippled background.

Description of holotype. Adult male with following dimensions (in mm): SVL 39.6, HeadD 4.8, HeadL 9.5, HeadW 7.4, CrusL 5.2, ForeaL 5.0, TrunkL 13.2, NarEye 2.9, SnEye 4.7, EyeEar 2.6, IntNarDist 1.0, IntOrbDist 4.7, OrbitL 2.0, RosW 1.4, RosL 0.9. Summary meristic data are as follows: SupLab 10; InfLab 9; Internarials 0; 4FLam 5; 4TLam 5; pores 16.

A small (39.6 mm SVL) gecko (Fig. 3). Head slightly depressed (HD/HL 0.50), with a moderately long snout (SnEye/HeadL 0.49). Head moderately wide (HeadW/HeadL 0.78), widest at anterior edge of ear, tapers from mid eye to a rounded snout. Slight concavity in the canthal region, between interorbital and labial regions. Head narrows posteriorly to a wide neck (neck width divided by HeadW, 0.91). Eyes moderately large (OrbitL/HeadL 0.22), but less than 50% of snout length (OrbitL/SnEye 0.44), with a moderately sized vertical pupil. Ear openings moderately sized, circular in shape. Nostrils rounded, orientated antero-laterally, contacted by rostral, supranasal, two post nasals, and first supralabial scale, supranasals in broad contact, no internarial scale. Rostral scale with a deep squared base and roughly rectangular shape, rising to a shallow gable shape, with a deep medial groove extending ~50% of rostral height, 1.4 mm wide, 0.9 mm high (RosH/RosW 0.63). Supralabials 7, infralabials 6. Mental scale triangular in shape, widely separating the upper third of inner postmentals. Anterior edge of first infralabial scale rounded where in contact with mental scale. Inner postmental scales in contact with first and ~ ¼ of second infralabial scale, single pair of outer postmentals, with curved latero-postero edge, ~half the height of inner postmentals and ~30% smaller in area; outer postmentals in contact with second infralabials. Outer postmentals separated from the third infralabials by a series of enlarged scales (parinfralabials, King 1982, cited in Hutchinson et al. 2014) that border the ventral edge of the infralabials. Second infralabial notched where this series of parinfralabial scales begins (Fig. 6). On head, scales are largest on snout, up to three times larger than on crown of head, neck and body, and rounded and tightly packed.

Body short (TrunkL/SVL 0.33), moderately robust and slightly depressed. Dorsal body scales small and granular, generally homogenous in size, rounded and tightly juxtaposed; ventral body scales diamond-shaped, flattened and laterally more imbricate, up to four times larger than the very small, typically rounded and tightly packed scales on ventral surface of head and neck. Pre-cloacal pores 16, forming a long shallow chevron with apex orientated anteriorly, each scale with a large circular perforation in centre. Three enlarged, rounded and protruding cloacal spurs present on either side of cloaca. A single subcaudal pore is present in the centre of the base of the tail. Limbs moderate length relative to short trunk (ForeaL/SVL 0.13; CrusL/SVL 0.13), scales as for body but tending to overlap laterally and distally and more heterogeneous than those on dorsal surface; five digits on manus and pes, toe pads broadly expanded basally with subdigital lamellae present on all digits, digit one of manus and pes clawless, claws long and free, present on digits II–V, arising from dorsal surface of expanded toe pads and extending above and beyond toe pad. Distal row of dorsal scales on toe pads sharply pointed, forming a serrated ‘fringe’. Subdigital lamellae divided, 5 pairs on fourth finger, 5 pairs on fourth toe, all pairs in contact, apical lamella undivided, forming a small rounded wedge.

Tail original but incomplete (10.8 mm), broad and dorso-ventrally flattened at base, with minimal taper between base and break. At base 5.2 mm wide. Dorsal caudal scales small, granular and largely homogeneous, subcaudal scales flattened, overlapping, with rounded edge orientated posteriorly, forming a series of single series of narrow and transversely widened scales extending along length of the (incomplete) tail.

Colouration (in preservative). Background dorsal colour pale tan, pattern of faded off-white and dark brown ocelli of similar size, ocelli small (6–9 scales), scattered, not in contact, generally poorly defined. On shoulders, neck and crown of head pale ocelli smaller and more numerous, and dark markings form indistinct streaks and blotches. Single narrow dark streak emanating posteriorly from eye; limbs as for dorsum; ventral surfaces creamy yellow; dorsal surface of tail patterned with scattered pale and dark ocelli, not aligned into bands.

Variation. Summary measurements (in mm) for type and referred adults (8 males, 8 females) are as follows (mean/mode, with range in parentheses): SVL 36.6 (31.5–40.4); HeadL 8.9 (7.4–10.0); HeadW 7.5 (6.0–8.2); HeadD 3.9 (2.9 –4.8); ForeaL 4.1 (3.0–5.2); HindL 4.2 (2.9–6.2); TrunkL 14.3 (12.7–16.4); NarEye 2.7 (2.3–3.4); SnEye 3.8 (3.2– 4.7); EyeEar 2.4 (2.0–3.1); IntNarDist 1.1 (0.7–1.3); IntOrbDist 3.2 (2.5–4.7); OrbitL 2.0 (1.6– 2.5); RosH 0.9 (0.8–1.1); RosW 1.4 (1.3–1.7). Summary meristic data for the same individuals are as follows: SupLab 9 (7–10); InfLab 8 (6–9); Internarials 0 (0–1); Pores 14 (males only; 11–16); 4FLam 5 (4-5); 4TLam 5 (4– 6).

In most specimens the inner postmentals contact both first and (part of) second infralabials (Fig. 6), in a small number (n = 2) only the first infralabial is contacted. In one specimen the series of parinfralabials extends to the first infralabial, which is notched. In most specimens the supranasals are in broad contact above the rostral, however, in two specimens a tiny internasal scale is present.

Coloration in life (based on photographs of [genotyped] specimens CCM5144 and CCM5160 shown in Figs. 5 and 8): background dorsal colour golden to dark tan, densely stippled with fine cream flecks. Background overlaid with pattern of clearly defined small pale ocelli and generally larger dark blotches. Dark blotches irregular in shape, may have a yellowish-orange border. Posterior edge of a dark blotch occasionally contacts anterior edge of pale ocelli. Head with smaller pale ocelli and dark blotches, pattern on original tail and limbs consistent with that of body. Ocelli and blotches generally scattered and do not tend to coalesce to form transverse bands. Iris green-gold with fine dark brown reticulations.

Coloration in preservative (Fig. 4): background dorsal colour from pale to dark tan, with scattered large pale and dark ocelli, not forming regular bands or pattern. Pale ocelli diffuse to well defined, dark ocelli mid to very dark brown, generally poorly defined and with an indistinct gold wash surround, occasionally very bold. Pattern elements are primarily ocelli with occasional dark streaks on body; on limbs, as for body with generally smaller ocelli; on shoulders, head and neck dark pattern may form streaks and smears, pale ocelli generally smaller. The size, density and distribution of pale and dark pattern elements vary among individuals. Ventrum creamy-yellow and generally unpigmented, with exception of fine dark brown stippling along ventrolateral regions of head, limbs and tail scales. All tails broken, original sections as for body and limbs, regrown sections with diffuse dark streaks.

Habitat and ecology. This species is associated with small boulders and rock rubble. Individuals were collected from rocky habitats east of the Gulf Plains region (Figs. 1 and 7), where the flat treeless landscape changes to rolling stony hills, with areas of more complex sandstone. This species is often seen active on and around rocks at night, and can also be found sheltering beneath loose rocks during the day. This species is not generally seen on larger vertical rock faces that may be occupied by larger-bodied gecko species such as Oedura coggeri Bustard 1966 and Gehyra dubia Macleay, 1877 in this region.

Distribution. Gehyra einasleighensis sp. nov. is currently known from several locations within the Einasleigh Uplands bioregion in north-east Queensland. Known localities extend roughly across the base of Cape York Peninsula in a band from just east of Croydon in the west, to Petford in the east, and extend as far south as Mingela (Fig. 1).

Etymology. This species is named for the Einasleigh Uplands bioregion in which it occurs.

Comparisons. Gehyra einasleighensis 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 small size (max SVL <41 mm versus > 41 mm). Within Australia, Gehyra einasleighensis sp. nov. can be distinguished from all members of the Gehyra australis group by its smaller size (max SVL <41 mm versus > 41 mm), divided subdigital lamellae under expanded toepads (versus at least some undivided), and lower counts of lamellae (<7 versus > 7).

Gehyra einasleighensis sp. nov. can be distinguished from members of the G. variegata-punctata group that occur in the Australian Monsoonal Tropics (AMT) as follows: from Gehyra xenopus Storr, 1978 and Gehyra spheniscus Doughty, Palmer, Sistrom, Bauer and Donnellan, 2012 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 41 versus 79 mm); from G. occidentalis King, 1984 by a lower number of lamellae (4–6 versus 7–10) and small body size (max SVL 41 versus 76 mm); and from G. multiporosa Doughty et al. 2012 by having fewer pre-cloacal pores in males (11-16 versus 20-49).

Gehyra einasleighensis sp. nov. can be distinguished from all rock dwelling members of the G. variegatapunctata group from the Australian arid zone (see Hutchinson et al. 2014) by a combination of having fewer lamellae (4–6 versus 6–9 pairs), a smaller body size (max SVL <41 versus > 44 mm), and internasal scale generally absent (versus present). The most similar species in the arid zone group is Gehyra minuta King, 1982 which nonetheless attains larger body size (up to 45 mm) and has a higher range of subdigital lamellae (6–8, mean 7 pairs; King 1982) and dark markings on the dorsum as scattered flecks rather than discrete ocelli (see also Hutchinson et al. 2014). The new species differs from its closet relative, G. purpurascens in that the latter is much larger (adult SVL range 49-62 mm, mean 55 mm), has 7–8 subdigital lamellae and a grey, reticulated back pattern.

The Gehyra nana species complex, as currently recognised, is widely distributed across the Australian monsoonal tropics. With the description of Gehyra einasleighensis sp. nov., Gehyra nana is known to occur only to the west of the Gulf of Carpentaria, with the former species occurring to the east of the Gulf Plains in the Einasleigh Uplands bioregion. Regardless, Gehyra einasleighensis sp. nov. can be distinguished from all other G. nana group taxa by a combination of its small size (max SVL <41 versus > 41 mm), low number of lamellae (4–6 versus 5–8), and a mid-tan to golden dorsal colour with scattered pale ocelli and irregular dark-brown blotches on a stippled background.

Specimen records indicate that the distribution of Gehyra einasleighensis sp. nov. overlaps geographically with the larger-bodied G. dubia (E. V. pers. obs.; Atlas of Living Australia, accessed 08/07/15; Cogger 2014; Wilson & Swan 2013), and is possibly parapatric with G. versicolor Hutchinson, Sistrom, Donnellan and Hutchinson, 2014 in the south. Both species are readily differentiated from Gehyra einasleighensis sp. nov. by their larger body size, higher number of subdigital lamellae (which typically are undivided in G. dubia), dorsal patterns tending towards bars/reticulations (versus ocelli), and body colour of generally grey to grey-brown versus mid-tan to golden brown. Additionally, juvenile G. dubia may be the size of adult G. einasleighensis sp. nov. and have prominent spotting over the dorsal surface (see Fig. 8), which could cause confusion if they are not clearly observed in a field situation. However, G. einasleighensis sp. nov. is relatively stockier and wider at the base of the tail, and is generally encountered on small boulders, whereas G. dubia is more likely to be found on trees and large rock faces.