Ctenotus pallasotus, Rabosky & Doughty & Huang, 2017

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 : 21-22

Ctenotus pallasotus sp. nov.

Doughty & Rabosky

( Figs. 2 , 3 D, 8, 16)

Holotype. WAM R 170291, female, collected 24 km south-east of Paraburdoo , quadrat TCMB 03 of the Pilbara Biodiversity Survey, WA, Australia (23°20'23"S, 117°48'04"E) by L. Gibson & B. Johnson on 12 October 2005.

Measurements of holotype. SVL 56 mm; tail length 115 mm; HL 10.3; HW 6.6 mm; HD 5.3 mm; 4ToeL 9.4 mm; ToeLam 22; MBSR 28; SupLab 9 (left) and 8 (right); InfLab 9 (left) and 10 (right); supraciliaries 8; EarLob 3 each side.

Paratypes. WAM R 110668, male, North West Cape (22°24'09"S, 115°50'36"E) ; WAM R119931, male, 3.5 km north-east of Mt Brockman (22°28'S, 117°18'E) ; WAM R 141296, male, Cape Preston area (21°03'57"S, 116°08'57"E) ; WAM R 170219, male, 30 km west of Tom Price , quadrat TCMB 05 (22°43'12"S, 117°30'38"E) .

Diagnosis. A medium-large (to 65 mm SVL) elongate Ctenotus , nasals in contact, prefrontals in contact or not in contact, 26–30 mid-body scale rows, 21–25 compressed lamellae under toes with narrow callus, usually eight supralabials and supraciliary scales, six (occasionally eight) pale narrow longitudinal stripes on blackish-brown ground color, dorsal stripes not continuing on head to snout, tail not red or blue, an upper lateral row of spots present between the pale dorsolateral and lateral stripes with usually a broken pale lateral line from ear to forelimb with scattered spots on the sides of the neck (except the North West Cape population), dark vertebral stripe not continuing anteriorly to parietals (terminates 2–4 nuchal scales before), parietals with some blotching, pale dorsolateral stripe continues anteriorly to eye, pale paravertebral stripes join on tail at or posterior to level of heel of extended hindlimb, lower labial scales variably stippled.

Description of holotype. 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 well-developed, 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.

Nostril located in center of nasal scale and directed anteriorly, frontoparietals divided, supraoculars four (2nd largest), superciliaries eight, loreals two, preoculars two, presuboculars one, upper eyelid with translucent scales, lower eyelid scaly, ear opening D-shaped with ear lobules on anterior edge four (right) and three (left); 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.

Coloration of holotype. Simple pattern of light to medium blackish to reddish-brown background and six longitudinal stripes; 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; lateral stripe on forebody between forelimb and ear broken and/or wavy; a row of pale flecks or spots between pale dorsolateral and lateral lines and continuing along body to near hindlimbs; pale paravertebral stripes continue anteriorly to nuchals; dorsolateral stripes continue anteriorly to outer edge of fourth supraocular or posterior edge of eye; forebody with irregular pale blotches and dashes; purplishblack eyes partially visible through medial supraocular scales; ear lobules pale; lower labials variably stippled, especially near sutures; ventral surfaces pale and immaculate; distal portion of tail tan on dorsal surface with stripes only on lateral surfaces.

Variation. Variation in continuous and meristic characters is summarized in Table 1. Occasionally eight longitudinal stripes (versus six on the holotype). Lateral stripe on forebody between forelimb and ear typically broken and/or wavy but occasionally solid. 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 posterior to the level of the heel of extended leg.

Habitat. Found in a range of habitats from sand plains with spinifex, mulga and mallee woodlands on clay and rocky surfaces such as breakaways and the lower slopes of ridges.

Distribution. Occurs in the western Pilbara region of Western Australia, including the Hamersley Range and north to near Karratha and south to the Barlee Range in the Ashburton region. Also on the North West Cape, including Yardie Creek and Bullara Station ( Fig. 4 ).

Etymology. Derived from Greek pallaso meaning a besmattering of spots, and otus meaning ear, in reference to the scattered spots posterior to the ear opening that distinguish this species from C. duricola . Used as a noun in apposition. Suggested common name: Western Pilbara Lined Ctenotus .

Remarks. As anticipated by Storr (1975) in his earlier treatment of Ctenotus , the population on the Hamersley Range was sufficiently distinctive to warrant taxonomic recognition. Owing to the subtle differences between C. duricola and C. pallasotus sp. nov., Storr mooted subspecific status for these populations, but he lacked access to more specimens with which to base a more confident nomenclatural act. The genetic evidence, however, clearly indicates these two taxa are quite significantly diverged from each other, and are not even each other’s closest relatives in the mtDNA phylogram ( Fig. 9 ). This species joins other new lizard species recently described from the Hamersley Range and surrounds such as Underwoodisaurus seorsus Doughty & Oliver, 2011 , Varanus hamersleyensis Maryan, Oliver, Fitch, & O’Connell, 2014 , and Tympanocryptis diabolicus Doughty, Kealley, Shoo, & Melville, 2015 .

Figures

FIGURE 2. Photographs in life of Ctenotus duricola senso lato individuals. A) eastern form (clean morphology) — Skull Springs, eastern Pilbara, WA (WAM R 175335; photo: R. J. Ellis); B) eastern form—Gillam Siding, Abydos, WA (photo: B. Maryan); C) western form (spotted morphology) — Juna Downs, Hamersley Range, WA (photo: B. Maryan); D) western form—near Pannawonica, Hamersley Range, 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.

FIGURE 9. (A) Maximum likelihood phylogeny of cytochrome B sequences (n = 99) from C. duricola, C. piankai, C. rhabdotus sp. nov., and C. pallasotus sp. nov., with branch lengths proportional to the estimated number of substitutions that have occurred. Clades are labeled by their ultimate taxonomic designation. Black circles on interior nodes denote nodes with strong support from both maximum likelihood (bootstrap proportion> 0.99) and Bayesian (posterior probability> 0.99) phylogenetic analyses. (B) Geographic distribution of C. piankai (blue triangles) and C. rhabdotus sp. nov. (gray circles) mtDNA haplotypes. (C) Geographic distribution of C. duricola (red circles) and C. pallasotus sp. nov. (yellow triangles) haplotypes in the Pilbara region. Arrows (n = 3) denote individuals with mtDNA genotypes that are in conflict with the general geographic distribution of duricola and pallasotus - type haplotypes. Genome-wide RAD data for these individuals suggest that limited mtDNA introgression has occurred between C. pallasotus sp. nov. and C. duricola (see Fig. 10).