Pygopus robertsi, Oliver, Paul M., Couper, Patrick & Amey, Andrew, 2010

Oliver, Paul M., Couper, Patrick & Amey, Andrew, 2010, A new species of Pygopus (Pygopodidae; Gekkota; Squamata) from north-eastern Queensland, Zootaxa 2578, pp. 47-61 : 51-57

Pygopus robertsi sp. nov.

Figs. 1 , 2 A,C,E, 4A,B.

Holotype. QM J47145 , male, Little Forks, Shipton's Flat, via Cooktown, 15° 47' S, 145° 15' E, collected by Lewis Roberts (registered 28 Aug. 1987)

Paratypes. QM J3899, sex not determined, Yungaburra, 17° 16' 0" S, 145° 35' 0" E; QM J57778 , female, Heathlands area, 11° 44' 0" S, 142° 32' 0" E; QM J58986 , male, 10.5km NE of Heathlands, 11° 41' 0" S, 142° 39' 0"E.

Generic diagnosis. A species in the genus Pygopus as defined by the following combination of character states: dorsal surface of head covered with large and small scales, 3 to 5 postmental scales, 21 or more midbody scale rows, dorsal body scales usually keeled and adults of both sexes with 9 or more precloacal pores (Kluge 1974).

Specific diagnosis. Pygopus robertsi sp. nov. is a large, robust pygopodid (maximum SVL ~ 224 mm) with a rounded snout, precloacal pores> 10, ventrals <100, midbody scales in 21 rows, no dark collar on the head or neck, no dark patch beneath the nostril, dark pigmentation around the margins of the ventral scales (at least posteriorly), approximately nine rows of weakly keeled dorsal scales and supraciliaries in a single, continuous row. Further specific morphological comparisons are given in the results section above.

Description. Sample size = 4 (unless otherwise stated). SVL = 122–224 mm (mean = 187 mm). Proportions as %SVL: Tail (no original tails in sample but one tail with a regrown tip)> 176; HL = 7.4–9.5 (mean = 8.1); HW = 4.1–6.0 (n = 3, mean = 5.2); S = 3.1–4.2 (mean = 3.4); EE = 3.4–4.0 (mean = 3.6); hindlimb = 3.4–5.3 (mean = 4.7).

Head. Bullet-shaped with a rounded snout; rostral barely projecting between rostral supranasals; rostral supranasals in narrow to point contact with the first supralabial, anterior to the nostril; caudal supranasals present, in narrow contact with dorsal edge of nostril; frontonasal divided; rostral frontal and caudal frontal in broad contact; parietals in broad contact behind caudal frontal and bordered posteriorly by a small, centrally placed occipital scale (in three specimens – not present in holotype); a single postnasal in broad contact with first supralabial; loreals, left side 10–12 (mean = 11.25, mode = 12), right side 8–12 (mean = 10.5, mode = 11), heterogenous; preoculars, left side 8–13 (mean = 11.25, mode = 12), right side 9–14 (mean = 11, mode = 9); suboculars 3; supraoculars 2, first longest; supraciliaries in a single row ( Fig 2 C, thus only 5 interorbital scales present), left side 3–4 (mean = 3.75, mode = 4), right side 4, usually 2 in contact with first supraocular; supralabials, left side 7, right side 7 or 8 (mean = 7.25, mode = 7), fourth below centre of eye; infralabials 6 or 7 (mean = 6.75, mode = 7), first infralabials well separated by a single scale; second infralabials separated by 3–4 scale rows (mean = 3.25, mode = 3); third infralabials separated by 5–8 scales rows (mean = 6.75, mode = 7); pretemporal single; upper temporals, left side 1 or 2 (mean = 1.75, mode = 2), right side 2; nuchal scales 16–20 (mean = 17.5, mode 16); gular scales 16–18 (mean = 17.3, mode = 18).

Body. Weak to very weak unicarinate keeling ( Fig. 2 A) extending over 9 dorsal scale rows, weakest on the outermost row; midbody scale rows 21; ventral scales 93–96 (mean = 93.8, mode = 93); ventral body scales paired, transversely enlarged (BBS 71-76, mean = 73.25); precloacal pores 14; precloacal scales 3.

Hindlimb. 5–6 scales present on ventral margin of hindlimb (mean = 5.8, mode = 6).

Colouration in preservative. The dorsal surface of the body and tail is light to mid-grey and unmarked. The lower flanks are heavily patterned with dark stippling and larger white spots. The ventral scales are white to cream with a faint grey edging; this increases in intensity, becoming dark grey to black on the posterior third to half of the body. Some specimens have a series of faint grey chin straps and there is a dark, inconspicuous to prominent bar running vertically below the orbit, through the fourth supralabial, and extending to the infralabials or 1 to 2 scale rows beneath the infralabials. Photographs of P. robertsi sp. nov. in life ( Fig. 4 ) show a pinkish to rufous tinge to the dorsum and scattered pink scales on the lower flanks and ventral surface.

Summary data for holotype. (QM J47145 ): SVL = 186 mm; Tail = 327 mm, with regrown tip (36 mm); HL = 14.7 mm; HW = 9.64 mm; S = 6.22 mm; EE = 6.27 mm; hindlimb = 9.84 mm. Loreals 11; preoculars 8 (L) or 9 (R); suboculars 3; supraciliaries 3 (L) or 4 (R); supraoculars 2; supralabials 7, fourth below eye; infralabials 7 (L) or 6 (R); single scale row between first infralabials; 4 scale rows between second infralabials; 7 scale rows between third infralabials; pretemporal single; temporals 1 (L) or 2 (R); nuchals 20; gulars 18; midbody scale rows 21; ventrals 93; BBS 72; precloacals 3; very weak keels present on 9 dorsal scale rows; precloacal pores 14; 6 scales along ventral margin of hindlimb.

Distribution. Pygopus robertsi sp. nov. is only known from a few scattered localities in two apparently disjunct areas of north-eastern Queensland ( Fig. 5 ). The northernmost records are of two specimens from the Heathlands area (11° 41' S, 142° 39' E). The remaining specimens range from the Shipton's Flat area near Cooktown (15° 47' S, 145° 15' E), south to the Atherton Tableland (Yungaburra, 17° 16' S, 145° 35' E). An additional Pygopus specimen (QM J4635) from Irvinebank, Mt Misery (17° 28’ S, 145° 14’ E) was present in the Queensland Museum but was destroyed in 1964. If this specimen was also assignable to P. ro b e r t s i sp. nov. it extends the distribution of this species a little to the SW of the Yungaburra record. A local naturalist has also seen another Pygopus specimen ( Fig. 4 B) on the lower slopes of Mt Sampson (15° 48’ S, 145° 11’ E) (L. Roberts, pers. comm.).

Natural history and conservation status. All records of the southern population of Pygopus robertsi sp. nov. for which habitat data are available are from relatively dry woodland along the western edge of the main Wet Tropics rainforest block. The holotype (QM J47145 ) was collected at Little Forks on a ridge adjacent to the Annan River at around 300 m elevation in open bloodwood forest ( Corymbia nesophila ), with a sparse understorey of Xanthorrhoea and Casuarina above a grassy ground cover ( Fig. 6 ), and the specimen observed at Mt Sampson came from similar habitat. The single specimen of the northern population for which habitat data is available (paratype QM J57778 ) was collected near the road approaching the Heathlands ranger station in low (approx 2 m) regenerating heath (Barry Lyon, pers. comm.).

Despite its large size and moderately wide distribution, spanning a well-surveyed region, Pygopus robertsi sp. nov. remains poorly known and rare in museum collections. Whilst this may reflect true rarity it could also result from cryptic behaviour. Apparently suitable habitat (open woodland and heath) is moderately widespread, but has not received the same survey attention as nearby patches of rainforest. On this basis we suggest that P. robertsi sp. nov. be classified as data deficient, pending further studies.

Etymology. Named for Charles George Roberts who, with his brother Lewis, has assisted zoologists, botanists and ecologists with their field studies in north-east Queensland for over four decades. The Roberts brothers are recognised experts on the flora and fauna of the Cooktown area and Honorary Consultants to the Queensland Museum.

Figures

FIGURE 1. (A) Dorsal view of the head of Pygopus robertsi sp. nov. (holotype, QM J 47145). (B) Lateral view of the head of P. ro b e r t s i sp. nov. (holotype, QM J 47145). CF = caudal frontal, CS = Caudal supranasal, FN = frontonasals, IL = infralabial, L = loreals, M = mental, P = parietals, PF = prefrontal, PN = post nasal, PO = preoculars, PT = pretemporal, R = rostral, RF = rostral frontal, RS = rostral supranasals, SC = supraciliaries, SL = supralabials, SO = supraoculars, SUB = suboculars, T = upper temporals.

FIGURE 2. Upper row: degree of keeling on dorsal body scales. A) weak on body scales of P. robertsi sp. nov. (holotype, QM J 47145). B) strong on body scales of P. lepidopodus (QM J 47934) from south-eastern Queensland. Middle row: Scalation of supraciliary / supraocular junction. C) supraciliaries of P. robertsi sp. nov. (holotype, QM J 47145) in a single, continuous row. D) supraciliaries of P. lepidopodus (QM J 47934) in two rows along the posterior portion of the orbit. Lower row: Condition of scales on temporal region. E) smooth for P. robertsi sp. nov. (holotype, QM J 47145). F) weakly keeled for P. lepidopodus (QM J 47934) from south-eastern Queensland.

FIGURE 5. Map of Australia showing the localities for museum records of Pygopus robertsi sp. nov. (triangles) and Pygopus lepidopodus (circles). Grey symbols denote localities for specimens genetically typed in this study. Locality records are taken from the collections of the Australian Museum, Western Australian Museum, South Australian Museum, Museum Victoria, Queensland Museum and Australian National Wildlife collection.

FIGURE 6. Open forest habitat at the type locality of Pygopus robertsi sp. nov. - Little Forks, Shipton's Flat, via Cooktown, Queensland (photograph by Jeanette Covacevich).

FIGURE 4. A) Holotype of P. robertsi sp. nov., QM J 47145, in life (photograph by Steve Wilson). B) Pygopus robertsi sp. nov. in life, non-vouchered specimen from the lower slopes of Mt Sampson 15 ° 48 ' S, 145 ° 11 ' E (photograph by Lewis Roberts).