Tympanocryptis pseudopsephos, 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 : 107-110

Tympanocryptis pseudopsephos sp. nov.

Goldfields pebble-mimic dragons Figs. 5 E, 5F, 14, 15

Holotype. WAM R154790, an adult male collected 31 km south-west of Doolgunna Homestead (25°52'33"S, 119°01'41"E), Western Australia, on 5 April 2004 by B. Maryan and B. Budrey ( Fig. 14 ).

Paratypes. WAM R114550 (female), 67 km south of Capricorn Roadhouse, 18 km east of Bulloo Down homestead (24°00'S, 119°45'E); WAM R136459 (female), Norseman Area (32°12'S, 121°47'E); WAM R164347 (male), 46.1 km east of Leonora (28°51'36"S, 121°48'12"E); WAM R164350 (female), 11.8 km east of Leonora (28°54'23"S, 121°26'44"E); WAM R167478 (male), 49.5 km north of Leinster (27°22'36"S, 120°35'10"E).

Diagnosis. Distinguished from other Tympanocryptis by the following combination of character states: rotund body shape, presence of two pre-cloacal pores, lack of longitudinal stripes on the dorsum, presence of enlarged scales with raised spines arranged in short transverse rows of 4–7 scales, concave snout formed by protruding mouth, scales on snout rugose with feeble keels, rostral width ~1–2 times height, keels on scales of upper arm not aligned, well-defined row of enlarged scales at anterior and dorsal edge of thigh forming conspicuous ridge, scales on dorsal surface of thigh not aligned, ventrals smooth, and reddish-brown ground color, lacking lines but often possessing a dark charcoal-like wash over the head and dorsum.

Description. A small-bodied (to 56.5 mm SVL), rotund dragon; small head with blunt snout with protruding mouth; short neck; moderately short gracile limbs, ArmL%SVL—0.185 (0.016), LegL%SVL—0.235 (0.017); moderately short gracile digits; short tail. Head small, HeadL%SVL—0.307 (0.017), HeadW%SVL—0.258 (0.013), HeadD%SVL—0.158 (0.008); neck ~3/4 of widest part of head; snout short, SnoutL%HeadL—0.259 (0.025); snout straight or concave when viewed laterally, if concave then snout tip projects forward; line of mouth slightly projecting forming a shelf-like appearance, narrowing to blunt tip; canthus defined but rounded, forming continuous line with projecting brow ridge; nostril located below canthus in enlarged scale, opening projecting dorsally; eye moderate, EyeL%HeadL—0.258 (0.022); eyes with laterally-projecting scaly eyelids forming a fringe, often 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 ~ 1–2 times wider than tall; 10–15 supralabial scales, 4–5 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 times long as wide; 11–16 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-shaped and smooth; prominent gular fold.

Body dorsoventrally compressed, ovoid in dorsal view with widest part ~2 times wider than neck and pelvis; TrunkL%SVL—0.473 (0.048); dorsum with heterogeneous scales in size and shape; largest scales with sharp spines angled 10–30° posteriorly and ~4–7 times larger than smallest scales; large dorsal scales with spines tending to occur in transversely-aligned clusters of ~4–6; smaller dorsal scales rugose or with weak, low keels, 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-shaped and arranged in diagonal rows; ventral scales smooth, or at most with raised midline (no keel or protruding spine).

Limbs largely covered in elongate kite or teardrop-shaped scales with prominent low keels, spine usually protruding beyond distal edge of scale, interspersed with occasional small unkeeled scales; arms and legs moderately long, ArmL%SVL—0.185 (0.016), LegL%SVL—0.235 (0.017); scales on dorsal surface of upper arm large with keels tending not to align; keels of dorsal scales on lower arm tending to align, often 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 heterogeneous non-aligned 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 3–5 scales, positioned anterior to distal edges of cloaca, midway between anterior and posterior edge of leg; tail short and thin with blunt tip, TailL%SVL—1.268 (0.102); scattered enlarged scales aligning along most of the length of the tail to terminus; lateral surfaces of tail base with short protruding spines.

Measurements for the type series are presented in Table 5 .

Coloration and pattern. In life ( Figs. 5 E, 5F), ground color medium to dark reddish-brown, often with dark grayish black wash over head, dorsum, and limbs; in some individuals this is quite extensive (e.g. Fig. 5 F); limbs weakly banded; nuchal region dark brown with 3 pale stripes; tail with ~8 alternating bands of pale white and ground color, anterior edge of pale bands dark, pale bands sometimes coalescing to form continuous stripe along top of tail towards tip. In preservative, ground color usually a grayish-brown, dark blotching on dorsum and banding on limbs dark gray to brown ( Fig. 15 ); some individuals with dark stippling near gular fold; pale bands on tail yellowy-white; ventrum pale with yellow or light orange hue ( Fig. 14 ).

Habitat. Recorded from Mallee and Mulga woodlands, often with stones strewn on the ground.

Distribution. Widely distributed throughout the Goldfields region of Western Australia ( Fig. 1 ). From just outside the south-eastern edge of the Pilbara, then south to near Norseman. Two older western records are from Yalgoo (WAM R13639) and Dongara (WAM R13476), although the latter record is likely in error given the habitat preferences of this species. A recent eastern record (WAM R163342) is from Neale Junction towards the South Australian border.

Etymology. pseudopsephos means ‘false pebble’, with pseudo Latin for ‘false’ and psephos is Greek for ‘pebble’. The name is an allusion to the pebble-mimicking abilities of this species.

Comparisons with other species. Based on its widespread distribution, we provide comparisons of T. diabolicus sp. nov. to all species treated here except T. cephalus .

Tympanocryptis pseudopsephos sp. nov. is distinguished from T. gigas by smaller body size, more rotund body shape, concave (versus convex) snout, possessing enlarged scales on dorsum arranged in short transverse rows (versus slightly enlarged scales scattered on dorsum), conspicuous ridge on front of thigh formed by enlarged row of scales, and scales on top of thigh homogeneous.

Tympanocryptis pseudopsephos sp. nov. is distinguished from T. diabolicus sp. nov. by possessing enlarged dorsal scales in short transverse rows in rows of 4–7 scales (versus 2–5), snout concave (versus straight or convex), rostral scale width 2 times height (versus 3 times), keels of scales on upper arm not aligned, scales on upper thigh not aligned, and ventrals smooth or slightly raised (versus with low keels).

Tympanocryptis pseudopsephos sp. nov. is distinguished from T. fortescuensis sp. nov. by possessing enlarged dorsal scales in short transverse rows in rows of 4–7 scales (versus 2–5), concave snout (versus straight to convex), scales on snout rugose with feeble keels (versus with low keels), rostral scale 3 times wider than high (versus 2 times), keels on dorsal surface of upper arm not aligned, keels of scales on top of thigh not aligned (versus usually aligned), ventrals smooth or slightly raised (versus with low keels), and reddish-brown color overlain with black (versus light brown).

Remarks. Tympanocryptis pseudopsephos sp. nov. is usually the taxon depicted in field guides (e.g. Storr et al. 1983; Wilson & Knowles 1988; Wilson & Swan 2003; Cogger 2014), as this species is the most widelydistributed of the T. cephalus species-group members and therefore most likely to be encountered and photographed. This also extends to diagnoses and descriptions in such guides and keys, and also often in taxonomic treatments as well. For example, in Mitchell’s 1948 revision of the group, the specimen WAM R7067 figured under the T. cephalus cephalus section is a T. pseudopsephos sp. nov. from 48 km east of Kalgoorlie. Moreover, Mitchell commented that his description of the ‘inland form’ (i.e. pseudopsephos ) differed slightly from that in Günther’s (1867) original description, Boulenger’s (1885) figure, and photographs of the types sent to him by the Natural History Museum: ‘…the [two syntype] specimens...differ in scalation detail from inland specimens. It has been suggested to me by a fellow worker that this inland form should be described as a new race. However, after considering that no similar specimens have been taken, it is assumed that the type specimens are merely local variants, and not typical representatives of the species which Gunther in fact described.’ (p. 64). We now know that the syntypes were of true T. cephalus and that the ‘inland form’ is the distinct T. pseudopsephos sp. nov. Historically, a lack of specimens has hindered taxonomic understanding in Tympanocryptis , and indeed continues to hinder revision of other arid zone forms.

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 14. Holotype of Tympanocryptis pseudopsephos sp. nov. (scale bar = 1 cm).

FIGURE 15. Paratypes of Tympanocryptis pseudopsephos sp. nov. (scale bar = 1 cm).

Tables

TABLE 5. Summary of meristic (mm) and mensural data for the type series of Tympanocryptis psuedopsephos sp. nov.

R# 154790	164347	114550	167478	136459	164350
Sex Male	Male	Female	Male	Female	Female
SVL 49.5	44.5	52.5	46.5	49.5	44.5
TrunkL 18.6	19.3	21.7	25.1	21.3	20.3
TailL 69.5	55.5	73.0	68.0	58.5	55.0
HeadL 16.4	13.7	16.8	14.3	14.4	14.3
HeadW 13.1	11.7	13.7	12.7	12.6	11.2
HeadD 8.3	6.9	7.9	7.5	8.1	6.9
SnoutL 3.9	3.4	4.3	3.6	3.7	3.6
SnoutW 5.9	5.0	6.1	5.9	6.1	5.1
EyeL 4.1	3.7	3.8	3.8	3.8	3.5
InterOrb 1.8	1.7	1.7	1.8	2.1	2.3
ArmL 9.2	8.1	9.6	8.3	9.3	9.4
HeadL 7.3	6.4	8.5	7.3	7.8	8.9
LegL 12.4	10.8	12.7	11.2	11.5	11.2
FootL 15.5	12.0	14.6	13.8	14.0	13.5
HeadW/SVL 0.3	0.3	0.3	0.3	0.3	0.3
FootL/SVL 0.3	0.3	0.3	0.3	0.3	0.3
TailL/SVL 1.4	1.3	1.4	1.5	1.2	1.2