Ctenotus piankai Storr, 1969

Rabosky, Daniel L., Doughty, Paul & Huang, Huateng, 2017, Lizards in pinstripes: morphological and genomic evidence for two new species of scincid lizards within Ctenotus piankai Storr and C. duricola Storr (Reptilia: Scincidae) in the Australian arid zone, Zootaxa 4303 (1), pp. 1-26 : 14-16

Ctenotus piankai Storr, 1969 : p. 106.

Coarse Sands Ctenotus

( Figs. 1 , 3 A, 5, 13)

Holotype. WAM R30000 (field number—E. R.P. 10799), male, collected 24 mi [38 km] east-north-east of Laverton , Western Australia (28°31'S, 122°45'E) by E.R. & H.L. Pianka on 26 February 1967.

Measurements of holotype. SVL 44 mm; TL 99 mm; HL 8.3 mm; HW 5.8 mm; HD 4.7 mm; 4ToeL 7.3 mm; ToeLam 24; MBSR 24; SupLab 8; InfLab 9; supraciliaries 7; EarLob 3 each side.

Paratypes. Listed under ‘Material’ in the original description (n = 10): WAM R1 5723, female, Muggun, WA; ‘ERP, 1’ (now LACM 56067 ), 24 mi east-north-east of Laverton, WA; ‘ERP, 1’ ( LACM 56066 ), sex unknown, five miles north-east of Dunges Table, WA; ‘ERP, 5’ ( LACM 56068–72 ), sexes unknown, eight miles west of Neale Junction , WA; ‘ERP, 2’ ( LACM 56064–65 ), sexes unknown, 18 miles south of Neale Junction, WA.

Diagnosis. A small-bodied (to 53 mm SVL), elongate Ctenotus , nasals in contact, prefrontals in contact, 22 or 24 midbody scale rows, 18–23 compressed lamellae under toes with obtuse keel, usually eight supralabial and supraciliary scales; pattern including six (occasionally eight) pale narrow longitudinal stripes on a reddish-brown dorsum, at most a single upper mid-lateral row of spots or dashes, dorsal stripes not continuing on head to snout, tail not red or blue, pale lateral stripe approximately twice as wide as pale paravertebral and dorsolateral stripes, dark vertebral stripe terminates on nuchals (not contacting parietals), pale dorsolateral stripe not continuing anteriorly to eye (broken), pale upper lateral stripe between ear and forelimb usually continuous, lower lateral stripe (if present) on fore-body solid or broken, pale paravertebral stripes join on tail at or posterior to level of heel of extended hind limb, lower labial scales immaculate.

Description. Head triangular, with snout narrowing to rounded tip; body long and cylindrical with flattened ventrum, neck only weakly constricted from head and body, concavity posterior to forelimbs; limbs short and welldeveloped, palmar and plantar surfaces with raised conical to triangular scales with rounded tips, pentadactyl, finger length: 3>4>2>5>1, toe length: 4>3>2>5>1, digits laterally compressed with obtuse keel, claws long and recurved; tail long and thin, tapering to a fine point.

Dorsal scales smooth, flat, reflective and imbricate, posterior edge of scale convex; scales on midline of dorsum widest, decreasing in size to ventrolateral edge; on tail, ventral scale rows along midline much wider than other scale rows, distal portion of tail often regenerated.

Nostril located in center of nasal scale, directed anteriorly, frontoparietals divided, prefrontals usually in contact, supraoculars four (2nd largest), supraciliaries 6–9, loreals two, preoculars two, presuboculars one, upper eyelid with translucent scales, lower eyelid scaly, ear opening D-shaped with 3–5 ear lobules on anterior edge, nuchals 2–8, mental with straight posterior edge, gulars imbricate decreasing in size posteriorly towards neck then increasing again on ventrum; two greatly enlarged scales anterior to cloaca. Variation in continuous and meristic characters is summarized in Table 1.

Coloration. Simple pattern of light to medium reddish-brown background and six (occasionally eight) longitudinal stripes; anterior portion of dorsal scale lighter than posterior portion; vertebral stripe darker than other areas of background color; four pale dorsal stripes narrow (<½ scale width), interrupted by encroachment of dark dorsal border of scale giving a dashed appearance; two lateral stripes wider (>½ scale width) and solid, continuing forwards to ear and on to upper labials and below eye; occasionally a row of poorly-formed pale flecks or spots between pale dorsolateral and lateral lines and usually only occurring on the fore-body but may continue to near hind limbs; paravertebral stripe continues anteriorly to nuchals (rarely in contact with parietals); dorsolateral stripe continues anteriorly to fourth supraocular (sometimes to eye), but broken on parietal and temporal scales; occasional short pale lower lateral stripe below upper lateral stripe from below angle of jaw to arm; purplish-black eyes visible through medial supraocular scales; ear lobules pale; lower labials and all ventral surfaces pale and immaculate; ground color of legs, arms, and tail light reddish-brown to tan; arm with 4–6 faint alternating light and dark longitudinal stripes; leg with 6–8 contrasting light and dark stripes; on tail, pale paravertebral stripes usually join at the level of the heel of extended leg; distal portion of tail tan on dorsal surface with stripes only on lateral surfaces.

Habitat. An inhabitant of sand dunes and plains with spinifex grasses (especially Triodia basedowii ), with which they are closely associated ( Pianka 1986). Dietary analysis of more than 150 individual lizards from the Great Victoria Desert suggests that the diet of C. piankai is dominated by true bugs (Hemiptera) and spiders ( Pianka 1986; Goodyear & Pianka 2011).

Distribution. Widely distributed in the western and central arid zone in Western Australia, north-western South Australia, the southern half of the Northern Territory and extending as far east as the Simpson Desert in far western Queensland (QM [Queensland Museum] J85419 ) ( Fig. 4 ). In Western Australia, occurs on sandy substrates as far north as the northern edge of the Tanami and Great Sandy deserts and has been found as far north as the Wolfe Creek meteor crater (UMMZ [University of Michigan Museum of Zoology] #242644).

Etymology. ‘Named after Dr Eric R. Pianka, in appreciation of his intensive research on the ecology of our desert lizards.’ ( Storr 1969, p. 106).

Remarks. This species was extensively studied in E.R. Pianka’s studies of the ecology of desert lizards in the Great Victoria Desert of Western Australia (summarized in Pianka 1986). The lizards collected from his studies form the majority of specimens of this species held in the WAM collections.

Figures

FIGURE 1. Photographs in life of Ctenotus piankai senso lato individuals. A) Yamarna, WA (photo: M. Peterson); B) Birksgate Range, SA (SAMA R 45385; photo: M. Hutchinson); C) Mornington Station, WA (photo: S. L. Macdonald); D) Tanami Desert, WA (photo: G. Harold).

FIGURE 3. Lateral-dorsal perspective of the forebodies of Ctenotus. From top to bottom: A) C. piankai (WAM R 108934), B) C. rhabdotus sp. nov. (WAM R 110581), C) C. duricola (WAM R 111876), and D) C. pallasotus sp. nov. (WAM R 119931). Scale bar is 10 mm.

FIGURE 4. (A) Geographic distribution of morphological forms within the nominate species ‘ C. piankai ’ (blue triangles, gray circles) and ‘ C. duricola ’ (red circles, yellow triangles). Relative to C. piankai from the interior deserts (blue triangles), northern populations from the Kimberley, Ord, Victoria River and northern Tanami desert (gray circles) are characterized by darker ground coloration, more midbody scale rows, and dorsal stripes that extend anteriorly onto the parietal scales (Figs. 1, 3). (B) Distribution of ‘ clean’ (red circles) and ‘ spotted’ (yellow triangles) morphological forms within ‘ C. duricola ’ in the Pilbara region of Western Australia. The ‘ clean’ morphology (Figs. 2 A, B; Fig. 3 C) is largely restricted to the eastern Pilbara, although several individuals from the westernmost edge of the range of C. duricola (North West Cape and Barrow Island) were observed to have this morphology. Several geographic features of north-western Australia discussed in the text are labeled in Fig. 4 B: NWC, North West Cape peninsula; D, De Grey River; F: Fortescue River Basin, AR, Ashburton River.