Oedura jowalbinna, Hoskin, Conrad J. & Higgie, Megan, 2008

Hoskin, Conrad J. & Higgie, Megan, 2008, A new species of velvet gecko (Diplodactylidae: Oedura) from north-east Queensland, Australia, Zootaxa 1788, pp. 21-36 : 25-33

Oedura jowalbinna sp. nov.

Figs 1 G and 3

Quinkan Velvet Gecko

Material examined: Holotype: QMJ85932, female, Pine Tree Ck, Jowalbinna Station, 34 km south-west of Laura, north-east Queensland (15°45′30″S, 144°12′15″E, elevation 250 m), C. J. Hoskin and M. Higgie, 23 November 2007. Paratype: QMJ85933, male, collection details as for holotype.

Additional material: Eight individuals were captured in the field. Morphological measurements, descriptions of colour pattern, and notes on breeding biology were recorded from seven of these individuals (Table 2), with one female escaping before morphological measurements were taken. Two of these individuals were collected (holotype and paratype), while the remaining six individuals were released due to uncertainty over the conservation status of the species.

Diagnosis: Oedura jowalbinna sp. nov. is a robust, medium-sized (SVL 60–69 mm) velvet gecko that can only be confused with its congeners. Oedura jowalbinna sp. nov. has a unique dorsal colour pattern ( Figs 1 G, 3A–C). The dorsal surface of the body, head and limbs are pale pinkish grey with faint freckling, and the only distinct markings are two pale, dark-edged bands—one across the neck, the other across the base of the tail. The original tail is yellow with small dark spots.

Etymology: jowalbinna is the name of the cattle station on which the species was discovered. The common name ‘ Quinkan Gecko’ is used because the sandstone escarpments of the Laura region are commonly referred to as the Quinkan region. Quinkans are ancestral spirit people that inhabit the sandstone escarpments in the Laura region (Ang-Gnarra Aboriginal Corporation 1995) and are commonly depicted at rock art sites, including at the type locality.

Measurements and scale counts of holotype: QMJ85932 (female) SVL = 60.2 mm; T = 34.7 (original); HL = 15.3 mm; HW = 11.9 mm; HD = 5.2 mm; S = 6.4 mm; EE = 5.6 mm; NL = 14.5 mm; AG = 26.8 mm; L1 = 18.9 mm; FL = 7.7 mm; L2 = 24.1 mm; HLL = 9.7 mm; 21 interorbitals; 2 scales contacting dorsal edge of rostral; rostral groove 1/3 of rostral depth; 6 scales bordering nostril; 11 supralabials; 12 infralabials; 6 rows of enlarged postmental scales; 3 scales bordering posterior edge of mental; postcloacal tubercules 1/1; no preanal pores evident; lamellae 1st toe = 6, 2nd toe = 6, 3rd toe = 7, 4th toe = 6, 5th toe = 6; lamellae 1st finger = 6, 2nd finger = 6, 3rd finger = 6, 4th finger = 6, 5th finger = 6.

Description of type series: Data presented as range followed by mean in brackets, n = 2. Measurements. SVL (mm): 60.2–61.6 (60.9); T = 34.7–36.8 (35.8); HL = 15.0–15.3 (15.1); HW = 11.5–11.9 (11.7); HD = 5.2–5.6 (5.4); S = 6.4–6.8 (6.6); EE = 5.6–5.6 (5.6); NL = 13.7–14.5 (14.1); AG = 26.8–27.6 (27.2); L1 = 18.9–19.4 (19.1); FL = 7.6–7.7 (7.6); L2 = 24.1–24.8 (24.5); HLL = 9.5–9.7 (9.6). Proportions as % SVL. T% = 57.6–59.8 (58.7); HL% = 24.3–25.4 (24.8); HW% = 18.6–19.7 (19.2); HD% = 8.6–9.0 (8.8); S% = 10.7–11.0 (10.8); EE% = 9.1–9.3 (9.2); NL% = 22.3–24.1 (23.2); AG% = 44.4–44.7 (44.6); L1% = 31.3–31.4 (31.4); FL% = 12.3–12.8 (12.5); L2 = 40.0–40.3 (40.2); HLL% = 15.4–16.1 (15.7).

Head. Narrow, elongate, moderately depressed, distinct from neck; head width 76.6–77.7% (77.2%) head length; head depth 43.8–48.5% (46.1%) head width; covered in small granules with slightly larger granules on the dorsal and lateral surfaces of the snout; 21 interorbital scales; rostral approximately twice as wide as deep, partially divided vertically by a medial groove (rostral groove 1/3 of rostral depth); rostral shield contacting nostril, bordered by 2 scales along its dorsal edge and the 1st supralabial on each side; 6 scales bordering nasal opening; 11–12 (11.5) supralabials, 1st supralabial narrower than 2nd supralabial, 1st supralabial taller than 2nd; 12 infralabials; 7 rows of noticeably enlarged granules extending back from mental scale, decreasing in size towards small ventral scales; ear opening small and horizontally elongate. Body. Moderately robust, slightly depressed, slightly pear-shaped, covered in small granules; granules on ventral surface about the same size as those on dorsum; granules on lateral and dorsolateral surfaces arranged as transverse rows; 1 enlarged postcloacal tubercule behind the lower posterior margin of the thigh in both sexes (better defined in males). A medially broken row of 15 preanal pores (8 on left side, 7 on right side) present in mature male, extending to underside of thigh; preanal pores not evident in female. Limbs. Moderately short and stout; digits dorsoventrally compressed and expanded distally, each with an enlarged pair of apical lamellae followed by a transverse series of lamellae that are divided distally and single proximally; apical pair of lamellae discontinuous with other lamellae; hindlimb with 5–6 (5.5) enlarged lamellae (including apical pair) on 1st toe, 6 on 2nd toe, 7 on 3rd toe, 6–7 (6.5) on 4th toe and 6 on 5th toe; basal webbing evident between digits 2, 3 and 4 of hindlimb, small between digits 2 and 3, and moderate between digits 3 and 4; forelimb with 6 enlarged lamellae (including apical pair) on 1st finger, 5–6 on 2nd finger, 6 on 3rd finger, 6 on 4th finger and 6 on 5th finger. Original tail. Relatively short, tapered; scales arranged in concentric rings, about the same size on the dorsal and on ventral surfaces. Regenerated tail. Not known.

Pattern in spirit ( Fig. 1 G): Pattern of holotype and paratype very similar. Background colour of dorsal and lateral surfaces pale grey. Dorsal and lateral surfaces of back and limbs mottled/freckled with light brown markings; faint to absent along the vertebral zone. Top of head even grey. Distinct pale, dark-edged band across neck; pale band sweeps forward unbroken to the snout enclosing ear and running along lower jaw and supralabials; anterior dark edging passes through eye to snout. Distinct pale, dark-edged band across base of tail. Dorsal and lateral surfaces of tail grey with distinct, small, brown, evenly spaced dots. Lower ventral surfaces and ventral surfaces of body, head and limbs cream, except for grey belly and pinkish chin. Underside of hands and feet grey. Postanal tubercles white. Ventral surface of tail pale with faint, grey, irregular mottling.

Measurements of live individuals: Table 2 summarises measurements from seven live individuals (including the holotype and paratype) in the field. The holotype and paratype showed 1.3% and 3.8% shrinkage, respectively, between SVL measurement alive and preserved.

Pattern in life ( Fig. 3 ): Pattern was highly consistent across all individuals (N = 8), varying only in brightness. Background colour of dorsal and lateral surfaces pale pinkish grey. Dorsal and lateral surfaces of back and limbs freckled with light brown markings, markings fade out to become absent towards the vertebral TABLE 2. Field measurements of female (N = 3) and male (N = 4) O. jowalbinna sp. nov. from the type locality on Jowalbinna Station. All individuals had original tails.

zone. Freckling is very faint to almost completely absent in some individuals, such that they appear unmarked. Fingers pale. Top of head unmarked, even pinkish grey. Distinct pale, dark-edged band across neck, sweeping forward to the snout; anterior dark edge of band passes from snout, through eye and over nape; pale band becomes white from in front of ear, along jaw to snout. Distinct pale, dark-edged band across base of tail. Dorsal and lateral surfaces of tail yellow or golden with distinct or diffuse small brown dots or grey mottling. Lower ventral surfaces and ventral surfaces of body, head and limbs pale pinkish. Postanal tubercles and lamellae of hands and feet white. Ventral surface of tail creamy yellow, with or without diffuse grey mottling. Eye very dark brown to black.

Comparison with other taxa: Colour pattern obviously differentiates Oedura jowalbinna sp. nov. from its congeners. The dorsal pattern of Oedura jowalbinna sp. nov., consisting of a distinct band across the neck and across the base of tail separated by a back lacking distinct patterning, differs from all other Oedura species. The other Oedura have heavily marked dorsal patterns of bands, spots, blotches or zigzags that are consistent along the length of the dorsum. Furthermore, the combination of grey body and yellow tail also distinguishes O. jowalbinna sp. nov. from its congeners.

Some aspects of the external appearance of O. jowalbinna sp. nov. (e.g. pale colouration, weak pattern, relatively narrow head) show some similarities to other sandstone species of northern Australia. Oedura jowalbinna sp. nov. differs from these species by the characters above, and furthermore by lacking conspicuous lateral toe fringing (versus O. filicipoda ), having more than three pairs of large, divided lamellae on the fourth toe (versus O. gracilis ), being of smaller size (versus O. filicipoda , O. gracilis and O. gemmata ), and by its robust form and lack of a long, slender tail (versus O. gracilis and O. obscura ).

Oedura jowalbinna sp. nov. co-occurs at the type locality with O. castelnaui and O. rhombifer . The dorsal pattern of O. castelnaui ( Fig. 1 A), consisting of bold, crescent-shaped bands, differs obviously from that of O. jowalbinna sp. nov. ( Fig. 1 G). Oedura castelnaui is also a considerably larger species (Table 1, Fig. 2 ). Oedura rhombifer differs from O. jowalbinna sp. nov. in being slender, having a long slender tail, having a continuous zigzag vertebral band, and in having minute dorsal scales that are noticeably smaller than the ventrals. Although not recorded at the type locality, O. coggeri and O. monilis also occur in north-east Queensland. Oedura coggeri has been collected from south of the Laura sandstones, in the Palmer River region (16°09′S, 144°08′E), approximately 38 km south-west of the type locality of O. jowalbinna sp. nov. The closest specimens of O. monilis were collected from Forty Mile Scrub National Park (18°08′S, 144°49′E), approximately 270 km south of the type locality of O. jowalbinna sp. nov. (Queensland Museum data). Oedura coggeri ( Fig. 1 C–F) and O. monilis ( Fig. 1 B) both have heavily marked dorsal surfaces that vary from being spotted to banded and do not resemble the distinctive dorsal pattern of O. jowalbinna sp. nov. ( Fig. 1 G). These two species are also generally larger than O. jowalbinna sp. nov. (Table 1, Fig. 2 ).

Oedura jowalbinna sp. nov. shows greatest similarity in body size, body shape and scalation to O. coggeri and O. monilis . However, O. jowalbinna sp. nov. clearly differs from these two species in multivariate analyses of morphology and scalation due to its generally smaller size and combination of higher interorbital, infralabial and supralabial scale counts, and lower total subdigital lamellae scale count ( Fig. 2 , Table 1). Considered individually, some of these traits are non-overlapping (Table 1), however, more individuals of O. jowalbinna sp. nov. need to be assessed to determine the full range of variation in these traits.

Distribution: Only known from the type locality, heavily dissected sandstone escarpment in the headwaters of Pine Tree Creek, Jowalbinna station, 34 km south-west of the town of Laura, north-east Queensland ( Fig. 4 ). All individuals were found within approximately 300 m of each other. The type locality is part of the Dalrymple sandstones of the Battle Camp Formation (‘Laura sandstones’), an extensive area of sandstone escarpments extending from Bathurst Bay to south-west of Laura ( De Keyser & Lucas 1968). The habitat occupied at the type locality appears similar to that seen in other areas of the Laura sandstones and therefore O. jowalbinna sp. nov. may be more widely distributed. We did not find the species during a gecko survey of the sandstone escarpment in the headwaters of Brady Creek (10 km south-east of the type locality) two days prior to the discovery of the species. Further, this species was not found on previous gecko surveys by us and others on sandstone outcrops south-east of the town of Laura (~ 35 km north-east of the type locality). However, these surveys represent limited survey effort given the extent of the sandstone escarpments in the Laura region.

Habitat and habits: Oedura jowalbinna sp. nov. appears to be a rock-restricted species. All eight individuals were found at night on the underside of rock overhangs along the base of a linked series of 5–15 m high sandstone walls ( Fig. 5 ). Individuals were generally found along east facing walls. No individuals were found on exposed rock surfaces, on trees amongst the rocks, or in the surrounding open eucalypt woodland. Sandstone at the type locality is heavily weathered, with deep cracks and holes, and large overhangs. Sandstone in the overhangs is pale sandy yellow or orange in colour, while that on the exposed surfaces is dark grey.

Individuals were found between 19:30–23:30 on the 22 and 23 November 2007. Conditions were warm and humid (air temperature approximately 28 °C) and there were localised storms in the area. Four males and four females were found. All were adult and appeared to have original tails. There was no detectable difference between males and females in terms of body size, body shape or colour pattern. Three of the four females were gravid, each carrying two large white eggs visible through the skin on the ventral surface. Some individuals made a thin, high pitched ‘peep’ when being handled and some made a soft growl when held in cloth bags. Small crickets were common on the underside of the overhangs and may represent a significant component of the arthropod prey.

Other geckos found occupying the rock habitat at the type locality were Cyrtodactylus louisiadensis De Vis 1892 , Gehyra dubia Macleay 1877 , and Oedura rhombifer . The surrounding forest was open eucalypt woodland, some of which had been burnt in the last couple of years. Geckos found in the eucalypt woodland were Oedura castelnaui , Gehyra dubia and Heteronotia binoei Gray 1845 .

Conservation: Oedura jowalbinna sp. nov. is only known from one site, where it is moderately common. No threats to the survival of this species at the type locality were apparent. Further surveys across the Laura sandstones are required to determine the distribution and abundance of O. jowalbinna sp. nov.

Figures

FIGURE 1. Comparison of size and dorsal pattern of four velvet geckos occurring in north-east Queensland: (A) O. castelnaui (QMJ 70404) – size large, dorsal pattern of bold crescent-shaped bands; (B) O. monilis (QMJ 75537) – size large, dorsal pattern typically consists of mottling overlain by a vertebral series of paired blotches (may be joined to form ‘ dumb-bells’ or bars); (C, D, E, F) O. coggeri (QMJ 69867, QMJ 79611, QMJ 70085, QMJ 74119) – size and dorsal pattern highly variable, size large to moderate, dorsal pattern ranging from irregularly blotched, banded, to spotted; (G) O. jowalbinna sp. nov. (QMJ 85932, holotype) – size moderate, dorsal pattern restricted to distinct band on neck and base of tail, otherwise back faintly speckled, tail with small dark spots.

FIGURE 2. Separation of Oedura jowalbinna sp. nov. from O. coggeri, O. monilis and O. castelnaui, on both morphological and scalation traits. Morphology PC 1 (x-axis) encompasses 83 % of the variation in morphological traits among the specimens measured and is a multivariate representation of body size (high values represent large body size, while low values represent small body size). Scalation PC 1 (y-axis) encompasses 65 % of the variation in scale count traits among the specimens measured (high values represent high interorbital, supralabial and infralabial scale counts relative to a low total hindlimb subdigital lamellae count, while low values represent low interorbital, supralabial and infralabial scale counts with a high hindlimb subdigital lamellae count). — O. jowalbinna sp. nov., Ϛ— O. coggeri, — O. monilis, ˖ — O. castelnaui.

FIGURE 3. Oedura jowalbinna sp. nov. in life: (A) male; (B) gravid female; (C) female, QMJ 85932, holotype; (D) male, ventral view.

FIGURE 4. Map of north-east Queensland, showing the type locality of Oedura jowalbinna sp. nov. ().

FIGURE 5. Sandstone habitat of Oedura jowalbinna sp. nov. at the type locality.