Oedura fimbria, Oliver, Paul M. & Doughty, Paul, 2016

Oliver, Paul M. & Doughty, Paul, 2016, Systematic revision of the marbled velvet geckos (Oedura marmorata species complex, Diplodactylidae) from the Australian arid and semi-arid zones, Zootaxa 4088 (2), pp. 151-176 : 168-171

Oedura fimbria sp. nov.

Western marbled velvet gecko Figs. 5 , 9 , 10

Holotype. WAM R154783, adult male with original tail, Brockman Ridge, Western Australia, 23.3108°S, 119.9169°E, Western Australia, collected by J. Fraser on 5 April 2004.

Paratypes. All from Western Australia: WAM R105965, 7 km north of Mount Magnet (28.00°S, 117.88°E); WAM R119991, Hope Downs (23.01°S, 119.10°E); WAM R119993, Hope Downs (23.00°S, 119.12°E); WAM R129595, 120 km north-west of Newman (22.92°S, 118.88°E); WAM R129635, 120 km north-west of Newman (22.92°S, 119.02°E); WAM R135369, Mount Brockman (22.31°S, 117.32°E); WAM R154796–7, Walga Rock (27.40°S, 117.47°E); WAM R157504, WAM R157508, WAM R157516, Packsaddle Range (22.92°S, 118.89°E); WAM R157595, West Angelas (23.19°S, 118.86°E); WAM R160074, 32.5 km east-south-east of Meentheena Outcamp (21.33°S, 120.750°E); WAM R165150, 5 km north-north-west Python Pool (21.32°S, 117.23°E).

Referred material. All from Western Australia: WAM R52852, 12 km east of Tallering Peak (28.10°S, 115.75E); WAM R84004, 6 km north of Mount Magnet (28.03°S, 117.85°E); WAM R84365, WAM R84366, 17 km north-north-east Anketell homestead (27.90°S, 118.95°E); WAM R87544, 30 km south-south-west Glenburgh homestead (24.68°S, 115.00°E); WAM R97012, Woolgerong Rock (27.40°S, 117.38°E); WAM R106289, 7 km north Mount Magnet (28.00°S, 117.88°E); WAM R119086, Virgin Springs, Carnarvon Range (25.10°S, 120.72°E); WAM R119837, Yandicoogina (22.72°S, 119.02°E); WAM R129622, 120 km north-west Newman (22.92°S, 118.88°E); WAM R132296, Ulongunna Rock (27.12°S, 117.23°E); WAM R132626, Burrup Peninsula (20.60°S, 116.81°E); WAM R135445, Mount Brockman (22.31°S, 117.32°E); WAM R146593, WAM R146594, 40 km south-east Pouyouwuncubban (22.15°S, 119.02°E); WAM R157508, Packsaddle Range (22.92°S, 118.89°E); WAM R160066 58 km east-south-east Meentheema Outcamp (21.32°S, 121.00°E); WAM R165150, 5 km northnorth-west Python Pool (21.32°S, 117.23°E).

Diagnosis. A large (mean SVL 94 mm, max 104 mm) species in the O. marmorata complex, with a moderately broad head (HW/SVL 0.18–0.21), moderately long body length (Trk/SVL 0.42–0.53), tail moderately long (TL/SVL 0.65–0.80), narrower than head and roughly circular in cross-section, rostral 25–60% divided, apical lamellae wide (TW/SVL 0.027–0.036), subdigital lamellae in a flared series wider than apical pair on fingers 3–4, 13–26 precloacal pores in adult males, and basic dorsal colouration (especially on juveniles) usually including 5 light transverse bands.

Description. A large (to 104 mm SVL) and moderately elongate Oedura (Trk/SVL 0.40–0.53); head moderately wide (HW/SVL 0.18–0.21) and deep (HD/SVL 0.09–0.13). Rostral 25 to 60% divided, bordered dorsally by two nasals, nasals bordered dorsally by two relatively small supranasals and 2–4 (mode 3) small intervening scales. Supralabials 9–11 to midpoint of eye, 11–13 in total; infralabials 10–13. Limbs moderate (ArmL/SVL 0.12–0.15, LegL/SVL 0.14–0.17). Subdigital lamellae expanded and prominent, 7–10 under third finger, 8–10 under third toe, distal lamellae on digits either divided or deeply notched, apical pair distinctly larger (but not always wider) than and separated from other pairs, penultimate pair slightly narrower, subsequent pairs on digits 2–5 distinctly flared, proximal lamellae undivided. Original tail moderately long (TL/SVL 0.65–0.80) and narrow (TW/TL 0.13–0.17) with a slight ventral groove, varying from somewhat depressed to almost circular in cross-section, relative width and depth varies greatly depending on body condition; caudal scalation homogeneous. Fully regrown tails shorter (TL/SVL 0.51–0.66) and wider (TW/TL 0.18–0.26) than original tails.

In preservative, base colouration of dorsum dark purplish brown, with a highly variable amount of light cream flecking or blotching. Most adult specimens have 5–6 distinct to very indistinct pale light transverse dorsal bands with wide brown central regions, with a further 5–8 similar bands on the tail. In larger specimens, however, all traces of bands have been lost. The anterior (nuchal) light band generally joins or approaches a light lateral stripe that extends from the labial scales and above the tympanum. Bands are typically very faded and indistinct on adult specimens from the north of the range, but remain more conspicuous in specimens of all sizes from the south. Extensive further light flecking and blotches are present between the bands, and elsewhere on the dorsal and lateral surfaces of the head, torso and limbs; northern specimens tend to have many smaller flecks, while southern specimens have fewer larger flecks or reticulate blotches. On a small number of apparently aberrant specimens, the light pigmentation is very extensive and brown areas form narrow transverse bands. Venter plain light buff, sometimes with faint brownish tinge on the throat and the terminal lamellae. Regrown tails dark brown with varying amounts of light flecking, but no clear bands.

Hatchlings and small juveniles are dark purplish brown dorsally, with 5 sharply-defined light cream transverse bands on the torso, 5–7 additional light bands on the tail, and a narrow white labial stripe. The dorsum of the head tends to be lighter brown than the remainder of the body. With increasing size, the light transverse bands become less clearly defined and usually develop a wide brown mid-region. An additional very light creamish transverse band or series of blotches also develops at the approximate midpoint of the pre-existing light bands; light flecking and blotching across the body, limbs and tail also becomes increasingly apparent.

In life, the basic pattern and colouration of adults matches those of preserved specimens, however, the darker regions are purplish during the day, silvery grey at night, and light regions tend to be whitish to relatively bright yellow. Iris very dark brown.

Particulars of the holotype. WAM R154783, adult male with original tail (in mm): SVL 104.0, HW 19.3, HD 10.9, HL 24.6, EN 8.1, IN 3.7, IO 8.5, EYE 5.4, TrK 49.0, ArmL 13.2, LegL 16.4, TL 74, TW 12.2, TD 10.2, 3FW 3.1, 3TW 3.6. Scale counts: SuL 10(12), InF 10, CS 2/3, 3FL 9, 3TL 8, precloacal pores 26. Hemipenes everted, right 10.2 mm long, left 7.6 mm long, pores in an almost continuous curved series separated by 2 poreless medial scales, two additional pore-bearing scales are also present posterior to the main series in the precloacal region.

Distribution and habitat. Occurs in the Pilbara, Gascoyne and Murchison regions of mid-western Western Australia ( Fig. 2 ). In the north (Pilbara), this species extends to the southern edge of the Great Sandy Desert, east to Karlamilyi National Park, and west to the Burrup Peninsula. In the south it occurs in the Gascoyne, western Murchison and Yalgoo regions, east as far as the Barlee Range, south to Mt Magnet and Gullwa, and east to the Little Sandy Desert. From collector’s notes associated with voucher specimens, this species was recorded as occurring on relatively massive ranges, rocky outcrops and breakaways, caves and gorges 114 times, whereas there are only 4 occurrences on trees and one under tin. We have only observed this species on rocky outcrops with large boulders (Pilbara) or on cliff faces (Kennedy Range).

Etymology. Fimbria is Latin for fringe in reference to the lateral fringes of expanded lamellae along the sides of the digits. Used as a noun in apposition.

Comparisons. Oedura fimbria sp. nov. is most similar to O. cincta and shares moderately large size (SVL> 100 mm), moderately long tail which tends towards rounded in cross-section and is not wider than the head, wide flared subdigital lamellae, dorsal pattern usually consisting of numerous poorly-defined light flecks and blotches and often thin light bands. The only clear diagnostic morphological character between the two speices is an incomplete rostral crease on O. fimbria sp. nov. (25–60% versus 60 [rarely]–100% [usually] of the rostral height). There are some differences in average for relative head length and body length, but ranges overlap extensively (see Table 1).

Oedura fimbria sp. nov. can be distinguished from other lineages in the O. marmorata species complex from northern Australia by possessing a longer (TL/SVL 0.65–0.80 versus 0.53–0.63) and narrower tail (always narrower than the head). It differs from O. bella in its larger size (max SVL 104 mm versus 92 mm), longer tail (TL/SVL 0.65–0.80 versus 0.49–0.65), wider terminal lamellae (3TW/SVL 0.23–0.36 versus 0.21–0.30) and prominently flared subdigital lamellae series—especially on fingers 3 and 4 (proximal lamellae wider than apical lamellae versus not wider).

Oedura fimbria sp. nov. can be distinguished from the three other species of Oedura in the Kimberley region in Western Australia as follows: from O. gracilis by its moderately long and swollen tail (versus very long [approaching length of body] and tapering) and in having subdigital lamellae series that is flared around the midpoint of the digit (versus tapering); from O. filicipoda in having a narrow tail that is not wider than the head and near circular in cross-section (versus wider and very flattened) and smaller eyes (EYE/SVL 0.051–0.064 versus 0.071–0.076); and from O. murrumanu in having a smaller eye (EYE/SVL 0.051–0.064 versus 0.067–0.069) and a longer rostral crease (> 25% [typically 40–60%] versus <25% of rostral height).

Figures

FIGURE 2. Distribution of three Oedura species resurrected or described in this paper: O. bella sp. nov. (blue, Gulf) from the Gulf Country, O. cincta (red, comprising Central and Eastern ESUs), and O. fimbria sp. nov. (yellow-brown, Western) from mid-western Australia. The distribution of the residual O. marmorata complex (green, comprising O. gemmata, true O. marmorata, and related lineages) in the Top End of northern Australia is also indicated. Darker regions indicate greater topographic complexity.

FIGURE 5. Species in the Oedura marmorata complex in life: A. O. cincta, Eastern ESU, Winton Region, Queensland; B. O. cincta, Eastern ESU, Danggalli Conservation Park, South Australia; C. O. cincta, central ESU, Simpson’s Gap, Northern Territory; D. O. cincta, central ESU, hatchling, Simpson’s Gap, Northern Territory; E. O. bella sp. nov., Doomadgee area, Queensland; F. O. bella sp. nov. holotype, 10 km south of Mt Isa, Queensland; G. O. fimbria sp. nov., Little Sandy Desert, Western Australia; H. O. fimbria sp. nov., Pannawonnica, Western Australia. Photographs: A, C – E. S. Macdonald; B. M. Hutchinson; F. P. M. Oliver; G. B. Maryan; H. R. Ellis.

FIGURE 9. Holotype (WAM R 154783) of Oedura fimbria sp. nov. in dorsal and ventral view. Scale bar = 1 cm.

FIGURE 10. Preserved specimens of Oedura fimbria sp. nov., showing range of variation in dorsal patterning. From top to bottom: WAM R 105965; WAM R 119991; WAM R 157595. Scale bar = 1 cm.