Gehyra granulum, Doughty & Bourke & Tedeschi & Pratt & Oliver & Palmer & Moritz, 2018

Doughty, Paul, Bourke, Gayleen, Tedeschi, Leonardo G., Pratt, Renae C., Oliver, Paul M., Palmer, Russell A. & Moritz, Craig, 2018, Species delimitation in the Gehyra nana (Squamata: Gekkonidae) complex: cryptic and divergent morphological evolution in the Australian Monsoonal Tropics, with the description of four new species, Zootaxa 4403 (2), pp. 201-244 : 220-223

Gehyra granulum sp. nov. Doughty, Palmer, Bourke, Tedeschi, Oliver & Moritz

Kimberley granular-toed gecko

(lineage nana 6)

Figs. 5 , 12–14

Holotype. WAM R176212 ( CCM1270 ) (male), collected on 22 May 2013 by G. Bourke, J. Bragg, R. Laver and P. Title, Bell Gorge water hole, Western Australia (16.99333°S; 125.20489°E).

Paratypes (10). WAM R158823 (male), Bigge Island (14.6019°S, 125.2039°E); WAM R168558 (BP01286) (female), Champagny Island (15.30°S, 124.25°E); WAM R168561 (BP01272) (female), Byam Martin Island (15.3833°S, 124.35°E); WAM R 171072 (BP00315) (male), Augustus Island (15.3900°S, 124.5931°E); WAM R171403 (male), Bachsten Creek bush camp (15.9897°S, 125.3294°E); WAM R171426 (female), Prince Regent River National Park (15.9810°S, 125.3731°E); WAM R176224 ( CCM 1339) (male), Gibb River Road, roadside (17.1189°S, 125.1329°E); WAM R176245 ( CCM 1492) (male), Gibb River Road (17.16653°S, 125.34761°E); NMV D75778 (male) and NMV D75774 (female), western end of Artesian Range (16.54834°S, 124.9961°E).

Diagnosis. A Gehyra with small body size (average 40 mm, 35–46 mm SVL), no flap of skin between limbs, dorsal half of rostral deeply furrowed with groove, 1 internasal scale present or absent, 2 postnasals of similar size, first supralabial slightly taller and narrower than second, 2 pairs of chin shields, snout short and convex in lateral view, first digit of manus and pes without claw, 5 or 6 divided subdigital lamellae on fourth toe, proximal lamellae usually separated by 1–3 granular scales (10% lack granules), mode of 15 (range 10–19) pre-cloacal pores in males arranged in shallow chevron pointing anteriorly. Background colouration in life dull tan to brown with scattered small pale spots and larger dark blotches or irregular lines on dorsum, often forming short transverse rows.

Description. Body size small (mean 40.1 mm, range 34.8–45.9 mm SVL), trunk length moderate (TrunkL/ SVL 0.40, 0.32–0.49), body shape slightly robust and dorsoventrally flattened, moderately flattened head (mean HD/HL 0.44, 0.29–0.54), with short snout (SnEye/HL 0.44, 0.36–0.52), convex to straight in lateral view, slight depression between curved poorly-defined canthal ridges; neck wide with only slight constriction. Limbs moderate length (ArmL/SVL 0.11, 0.08–0.14; HindL/SVL 0.12, 0.09–0.14); digits short; claw protruding from dorsal surface of expanded circular terminal toepad, no claws on anteriormost digit of manus and pes; 5 (occasionally 6) subdigital lamellae on fourth finger, usually 5 or 6 (a single individual with 7) subdigital lamellae on the fourth toe; first two proximal lamellae on digits separated by 1–3 granules, typically with 2 granules separating proximal pair and a single granule separating the next distal pair ( Fig. 14 ).

Nostrils rounded, directed laterally and dorsally, contacted by rostral, supranasal, two postnasals and first supralabial; supralabials 7–9; infralabials 7–8; rostral ~1.5 x wider than high with a deep furrow ~60% of rostral height, a fine medial groove extends 50–70% of the height of the scale from dorsal edge; supranasals rounded or rectangular, dorsal edge curved, ventral edge flat or curved and in contact with rostral, supranasals in contact in half of specimens, and the other half a single small internarial scale along dorsal edge of rostral present; 2 similarsized postnasals; mental narrow, usually angling inwards posterior to infralabials or continuing with straight sides to terminate in triangular point from 1/4 to 1/2 height of inner chin shields; outer chin shields smaller (~1/2 length) with rounded lateral-posterior edges, smaller irregular-sized granular scales lateral to posterior half of outer chin shields; inner chin shields in contact with second infralabial; first scale of parainfralabial row of scales usually forming a notch on postero-ventral edge of third (occasionally second) infralabial, with granular scales extending to contact second infralabial.

Scales on dorsum small, non-overlapping; scales on crown are small, scales near the eyes are larger, scales on snout large and rounded; slightly enlarged row of scales above supralabials; scales on ventrum flat and ~6– 8 x larger than those on dorsum, becoming granular anterior to arms; granular scales on gular region, gradually increasing in size towards parainfralabial row and infralabials; scales on ventral surface of thighs and anterior to cloaca enlarged and flat; medial row of scales on tail greatly enlarged and much wider than long, bordered laterally by a row of moderately enlarged scales, scales on dorsal and lateral surfaces of tail slightly enlarged and tending to be arranged in regular rows; regenerated tails with irregular scales not arranged in rows.

Males (n = 17) with a mode and mean of 15 (range 10–19) pre-cloacal pores forming a shallow chevron with the apex pointed anteriorly; pores penetrating scale; 1–2 enlarged protruding cloacal spurs to either side of cloaca (females with only slightly enlarged analogous scales); gravid females (36.1 mm and 37.9 mm SVL) with a single large egg. Tail cylindrical and moderately long, tapering to fine point.

Colouration. In life, background colour of dorsal surfaces light to dark tan with reddish hues; dark brown irregularly-shaped blotches or bars tending to be transversely orientated; larger dark markings interspersed with more numerous scattered fine pale white spots not in contact; a subtle lightening of the background colour along midline; usually no dark temporal streak posterior to eye; scattered dark and smaller pale spots on head with small pale spots more than twice as numerous as dark spots; snout slightly dark; supralabials lightly to darkly stippled with maculated appearance formed by hiatus of pigment near sutures; infralabials, mental, chin shields and gulars with light to heavy dark stippling; upper surfaces of limbs with small pale and dark spots continuing to dorsal surfaces of digits; ventrum pale off-white with light or no stippling in centre and heavier stippling towards lateral edges; dorsal and lateral surfaces of original tails with alternating pale and dark rows of spots; regenerated tails with an admixture of dark and pale scales; ventral surface of tail as for ventrum. In preservative, subtle reddish hues lost with background colour a medium-brown.

Habitat. This species has been collected from low rocks and rock faces in sandstone rock formations in open savannah woodlands with spinifex. Occasionally collected from trees, but only when in association with rocky outcrops. It is broadly sympatric with the larger-bodied species G. multiporosa , G. occidentalis , and G. pseudopunctata sp. nov. and with the more similarly sized G. spheniscus in the southwest Kimberley, and overlaps geographically with G. kimberleyi and true G. nana in the southern and eastern Kimberley.

Distribution. Gehyra granulum sp. nov. occurs in the northwest Kimberley of Western Australia. On the mainland, as far north as Mitchell Plateau and extending along the coast through the Prince Regent River National Park, extending as far south as Wilinggin National Park, with records from the Durack and Cockburn Ranges to the east, and one record near Warmun community on the Great Northern Highway in the south-eastern Kimberley. Occurs on many off-shore islands of the western Kimberley, with specimens collected from Katers, Bigge, Coronation, Augustus, Caffarelli, Storr, Sunday, Long, Wulalum, Lachlan, Hidden, North West Molema, Byam Martin, Champagny, Bathurst, Irvine, Gibbings, King Hall and Koolan islands.

Etymology. granulum (Latin) refers to the granular scales between the proximal subdigital lamellae that characterises this species.

Comparisons with other species. Gehyra granulum sp. nov. is most similar to other small-bodied Gehyra from the Kimberley. It differs from G. nana , G. girloorloo and G. pluroporosa sp. nov. by usually possessing 1–3 small granules on the proximal subdigital lamellae and often lacks an internarial scale. From G. spheniscus , another small-bodied Gehyra with granules on the digits, it differs by number of granules on proximal lamellae (1–3 vs a small wedge of 5–7; Fig. 14 ), fewer pre-cloacal pores in males (10–19 vs 21–27) and different colouration (reddish-brown with large dark and small pale spots vs purplish-brown with similar-sized dark and pale spots).

Figures

FIGURE 5. Photos in life of the species described herein. A) Gehyra nana (lineage nana2) (NTM R37597) from Bradshaw Field Training Area, NT (S. Mahony), B) G.nana (nanamulti) (WAM R174051) from Drysdale River National Park, WA (R.J. Ellis), C) G. paranana sp. nov. (NTM R37601) from Bradshaw Field Training Area, NT (S. Mahony), D) G. pseudopunctata sp. nov. (not collected) from near Halls Ck, WA (S. Zozaya), E) G. granulum sp. nov. (WAM R171403) from Prince Regent River National Park,WA (P.Doughty), F) G.granulum sp.nov. (WAMR168561) from Byam Martin Island(P.Doughty), G)G. pluraporosasp. nov. (WAM R174024) from Theda Station, WA (R.J. Ellis).

FIGURE 12. Holotype of Gehyra granulumsp. nov. (WAM R176212) from Bell Gorge, WA (scale bar = 10 mm).

FIGURE 13. Variation within Gehyra granulum sp. nov. (scale bar = 10 mm).

FIGURE 14. Comparison of the subdigital lamellae of G. nana (no additional granules), G. granulum sp. nov. (1 to 3 small granules dividing proximal lamellae, shown in red) and G. spheniscus (small wedge of granules that extends towards tip of digit) (drawing—L. Tedeschi).