Tympanocryptis diabolicus, Doughty, Paul, Kealley, Luke, Shoo, Luke P. & Melville, Jane, 2015

Doughty, Paul, Kealley, Luke, Shoo, Luke P. & Melville, Jane, 2015, Revision of the Western Australian pebble-mimic dragon species-group (Tympanocryptis cephalus: Reptilia: Agamidae), Zootaxa 4039 (1), pp. 85-117 : 100-103

Tympanocryptis diabolicus sp. nov.

Hamersley pebble-mimic dragons Figs. 5 C, 10, 11

Holotype. WAM R135413, an adult male collected at Mount Brockman (22°17'31"S, 117°16'23"E), Western Australia, on 20 November 1998 by S. Anstee ( Fig. 10 ).

Paratypes. WAM R135411 (male), Mount Brockman (22°17'31"S, 117°16'23"E); WAM R135412 (male), Mount Brockman (22°17'31"S, 117°16'23"E), WAM R135454 (male), Mount Brockman (22°17'31"S, 117°16'23"E), WAM R 170204 (male), 53 km north-north-west of Tom Price (22°18'21"S, 117°28'47"E); WAM R 170281 (male), 51 km east-south-east of Paraburdoo (23°17'33"S, 118°09'23"E)

Diagnosis. Distinguished from other Tympanocryptis by the following combination of character states: presence of two pre-cloacal pores, lack of longitudinal stripes on the dorsum, presence of enlarged scales with raised spines arranged in transverse rows of 2–5 scales or scattered on dorsum, snout straight or concave, scales on snout smooth to rugose with feeble keels, rostral width ~2–3 times height, keels on scales of upper arm aligned, well-defined row of enlarged scales at anterior and dorsal edge of thigh forming conspicuous ridge, scales on dorsal surface of thigh aligned, ventrals with low keels, and rich reddish-brown ground coloration with some irregular dark blotching along midline of dorsum.

Description. A small (to 60.5 mm SVL), rotund dragon; small head with blunt snout; short neck; moderately short gracile limbs, ArmL%SVL—0.189 (0.018), LegL%SVL—0.250 (0.017); gracile digits; short tail. Head small, HeadL%SVL—0.310 (0.018), HeadW%SVL—0.249 (0.016), HeadD%SVL—0.158 (0.010); neck ~3/4 of widest part of head; snout short, SnoutL%HeadL—0.256 (0.021); snout straight or concave when viewed laterally, if concave then snout tip projects forward, narrowing to blunt tip; canthus defined but rounded, forming a continuous line with projecting brow ridge; nostril located below canthus in enlarged scale, opening projecting dorsally and posteriorly; eye moderate, EyeL%HeadL—0.253 (0.019); eyes with laterally-projecting scaly eyelids forming a fringe, rarely projecting past brow when viewed dorsally; tympana covered with fine scales, encircled by scattered enlarged scales with raised apex; scales on snout rugose, occasionally with feeble unaligned keels; scales on crown slightly larger with feeble unaligned keels; scales on back of head small with few variably-sized low scattered spines; rostral scale ~2–3 times wider than tall; 10–14 supralabial scales, 5 rows of scales above supralabial row, keeled, uppermost row slightly larger with larger keels and continuing to temporal region, forming edge of eye socket; loosely defined cluster of enlarged spines at posterior and lateral corners of head; mental 1.5–2 times long as wide; 12–15 infralabials with low keels; 4–5 rows of scales below infralabials with low keels parallel to angle of jaw, creating a slightly terraced appearance; gulars kite or teardrop-shaped and smooth; prominent gular fold.

Body dorsoventrally compressed, ovoid in dorsal view with widest part ~1.5–2 times wider than neck and pelvis; TrunkL%SVL—0.463 (0.034); dorsum with heterogeneous scales in size and shape; largest scales with low spines angled 10–30° posteriorly and ~2–5 times larger than smallest scales; large dorsal scales with spines tending to occur in oblique or transversely-aligned clusters of ~2–6; smaller dorsal scales smooth to rugose, arranged in loose whorls around clusters of large, spiny scales; dorsolateral edge of pelvis always with a cluster of enlarged spines at posterior edge where skin is fused to bone; ventral scales homogeneous, approximately half the size of large dorsal scales, kite or teardrop-shaped and arranged in diagonal rows, median keels low.

Limbs covered in elongate kite or teardrop-shaped scales with prominent low keels, spine usually protruding beyond distal edge of scale; arms and legs moderately long, ArmL%SVL—0.189 (0.018), LegL%SVL—0.250 (0.017); scales on dorsal surface of upper arm large with keels aligned; keels of dorsal scales on lower arm aligned, forming lines that extend to hand and fingers; keels of ventral scales mostly aligned forming lines along the length of the arm to palmar surfaces; scales on underside of digit with two rows of spiny lamellae; claw long and recurved, lower portion terminating with circular opening, upper portion continuing past ultimate lamellae to form sharp claw; finger length: 4> 3> 2 = 5> 1; scales on legs kite or teardrop-shaped; tops of upper and lower leg with large non-aligned relatively homogeneous scales, elsewhere with low keels that align and extend to feet and toes; scales at insertion of limb to body small, rectangular and lacking keels; anterior edge of thigh with enlarged scales forming conspicuous ridge; abrupt transition from dorsal to posterior edge of leg (large to small scales); scales on underside of toes as for fingers; toe length: 4 >> 3> 2 = 5> 1.

Pre-cloacal pores 2, set among 3–6 scales, positioned anterior to distal edges of cloaca, midway between anterior and posterior edge of leg; tail moderately short and thin with blunt tip, TailL%SVL—1.317 (0.172); scattered enlarged scales aligning along most of the length of the tail to terminus; lateral surfaces of tail base with few, short protruding spines.

Measurements for the type series are presented in Table 3 .

Coloration and pattern. In life ( Fig. 5 C), ground color a rich reddish-brown with variable shading, often with grayish black wash over head, body, and limbs; limbs with subtle bands; nuchal region dark brown, interrupted by three short white lines edged with black; tail with ~8 alternating pale and ground color bands, anterior edge of pale bands edged with black, pale bands tending to coalesce on posterior half of tail forming pale stripe. In preservative, ground color fading to light grayish-brown, in some individuals dark blotches more well-defined and usually number 3–4, some individuals with no blotches but darkened dorsolateral zones (WAM R164063, R 170281; Fig. 11 ); axillary region often with darkened scales in mosaic pattern; ventral surfaces pale white or with reddish hue in some individuals (WAM R135413; Fig. 10 ).

Habitat. Little is known of this species’ habitat preferences from collector’s notes. This species was combined with T. fortescuensis sp. nov. in the analysis of the PBS data (Doughty et al. 2011), which indicated a strong preference for clayey substrates, with many of the sites having small rocks and pebbles strewn across the surface (McKenzie et al. 2009).

Distribution. Restricted to the Hamersley Range in the Pilbara region of Western Australia ( Fig. 1 ). Western records include a specimen from Mt De Courcey in the south-west Hamersley Range, Mt Brockman, and Tom Price. Other locations include Paraburdoo, Rhodes Ridge, Giles Point, and Turee Ck. The easternmost records are from Mt Newman. The distribution of T. diabolicus sp. nov. runs along the northern edge of the Hamersley range, in parallel to T. fortescuensis sp. nov. which occurs along the Fortescue Marsh.

Etymology. ‘ diabolicus ’ means ‘devil’ in Latin, in reference to the rich red coloration possessed by most individuals of this species. Used as a noun in apposition.

Comparisons with other species. Based on its central location relative to the distribution of the other taxa treated here, we provide comparisons of T. diabolicus sp. nov. to all of these species. Tympanocryptis diabolicus sp. nov. is distinguished from T. cephalus by possessing enlarged dorsal scales in short transverse rows in rows of 2–5 scales (versus 5–7), scales on snout rugose with feeble keels (versus with low keels), enlarged row of scales forming ridge on leading edge of thigh (versus poorly defined), and rich reddish-brown coloration with only weak blotching along midline (versus brown with dark blotches).

Tympanocryptis diabolicus sp. nov. is distinguished from T. gigas by smaller body size, more rotund body shape, enlarged scales on dorsum arranged in short transverse rows (versus slightly enlarged scales scattered on dorsum), keels on dorsal surface of upper arm aligned, conspicuous ridge on front of thigh formed by enlarged row of scales, scales on top of thigh homogeneous with keels forming lines, ventrals with low keels (versus smooth), and rich reddish-brown coloration with only weak blotching along midline (versus light brown with dark blotches in center of dorsum and anterior to legs).

Tympanocryptis diabolicus sp. nov. is distinguished T. pseudopsephos sp. nov. by rostral scale 3 times wider than high (versus 2 times), keels on dorsal surface of upper arm aligned, keels of scales on top of thigh aligned, and ventrals with low keels (versus smooth or slightly raised).

Tympanocryptis diabolicus sp. nov. is distinguished from the closely-related T. fortescuensis sp. nov. by scales on snout rugose with feeble keels (versus with low keels) and ground color a rich reddish-brown with some evidence of blotching along midline of dorsum (versus light brown rarely with blotching along midline).

Remarks. The genetic differences between T. diabolicus sp. nov. and T. fortescuensis sp. nov. are on the order of 5%, with an estimated time of divergence of 2.8 million years (Shoo et al. 2008). Although not as great differences among other Tympanocryptis species, we believe species recognition for this taxon is warranted owing to the strong overall genetic support presented here (Fig. 3) and in Shoo et al. (2008), the non-overlapping distribution of the species, and the two key morphological differences between the species: coloration and pattern, and the keeling on the snout.

Figures

FIGURE 1. Distribution map of the Tympanocryptis cephalus species-group in Western Australia.

FIGURE 5. Photographs in life of Tympanocryptis cephalus species-group members (left to right, top to bottom): a) T. cephalus (photo—G. Harold), b) T. gigas (M. Peterson), c) T. diabolicus sp. nov. (M. Peterson), d) T. fortescuensis sp. nov. (G. Harold), e) T. pseudopsephos sp. nov. — plain form (G. Harold), f) T. pseudopsephos sp. nov. — with charcoal wash on dorsum (G. Harold).

FIGURE 10. Holotype of Tympanocrtyptis diabolicus sp. nov. (scale bar = 1 cm).

FIGURE 11. Paratypes of Tympanocryptis diabolicus sp. nov. (scale bar = 1 cm).

Tables

TABLE 3. Summary of meristic (mm) and mensural data for the type series of Tympanocryptis diabolicus sp. nov.

R# 135413	135454	170204	135412	135411	170281
Sex Male	Male	Male	Male	Male	Male
SVL 54.5	60.5	47.5	60.0	58.5	59.0
TrunkL 24.7	28.8	22.8	27.9	27.8	26.7
TailL 71.5	84.5	63.0	57.0	58.0	78.5
HeadL 16.2	17.2	13.9	16.9	17.4	18.0
HeadW 13.0	13.4	11.7	13.4	12.8	13.5
HeadD 8.6	8.9	7.0	8.3	8.6	9.0
SnoutL 4.0	4.4	3.8	3.9	3.8	4.7
SnoutW 6.1	6.2	5.4	6.2	6.1	6.7
EyeL 4.2	4.7	3.7	4.2	4.3	4.2
InterOrb 1.7	1.9	2.0	2.1	2.2	2.3
ArmL 11.1	12.0	6.1	10.3	11.2	11.5
HandL 8.9	8.5	6.9	7.4	7.5	8.6
LegL 14.5	15.5	12.3	13.1	15.2	14.2
FootL 16.1	17.3	14.3	16.9	16.9	16.5
HeadW/SVL 0.2	0.2	0.3	0.2	0.2	0.2
FootL/SVL 0.3	0.3	0.3	0.3	0.3	0.3
TailL/SVL 1.3	1.4	1.3	1.0	1.0	1.3