Tympanocryptis fortescuensis, 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 : 104-106

Tympanocryptis fortescuensis sp. nov.

Fortescue pebble-mimic dragons Figs. 5 D, 12, 13

Holotype. WAM R158076, an adult male collected 4 km south-south-east of Wanna Wanna Pool (21°23'41"S, 117°10'14"E), Western Australia, on 9 October 2004 by J. K. Rolfe and B. Durrant ( Fig. 12 ).

Paratypes. WAM R108817 (male), 37 km north-north-east of Auski Roadhouse (22°03'S, 118°48'E); WAM R 110129 (male), 12 km east-south-east of Mount Billroth (21°39'45"S, 117°42'17"E); WAM R113625 (female), 37 km north-north-east of Auski Roadhouse (22°03'S, 118°49'E); WAM R 121974 (male), Roy Hill Station (22°34'18"S, 119°58'39"E); WAM R158074 (female), 4 km south-south-east of Wanna Wanna Pool (21°23'41"S, 117°10'14"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 on dorsum, snout straight or convex, scales on snout smooth with low 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 usually aligned, ventrals with low keels, and light reddish-brown coloration, often with blackish sides.

Description. A small to medium-sized (to 65.0 mm SVL), slightly rotund dragon; small head; blunt snout with slightly protruding mouth; short neck; moderately short gracile limbs, ArmL%SVL—0.196 (0.017), LegL%SVL— 0.259 (0.020); moderately short gracile digits; short tail. Head small, HeadL%SVL—0.307 (0.017), HeadW%SVL—0.235 (0.018), HeadD%SVL—0.155 (0.009); neck ~3/4 of widest part of head; snout short, SnoutL%HeadL—0.266 (0.016); snout convex, straight or slightly concave when viewed laterally, if concave then snout tip projects forward, 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 and posteriorly; eye moderate, EyeL%HeadL—0.248 (0.018); eyes with laterally-projecting scaly eyelids forming a fringe, rarely projecting past brow when viewed dorsally; tympana covered with fine scales, surrounded by several scattered enlarged scales with moderately raised apex; scales on snout rugose and usually with low unaligned keels; scales on crown slightly larger with moderately strong unaligned keels; scales on back of head small with several variably-sized low scattered spines; rostral scale ~2–3 times wider than tall; 11–15 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 1.5–2 times long as wide; 12–15 infralabials with low keels; 4–5 rows of scales below infralabials with medium to low keels parallel to angle of jaw, creating a terraced appearance; gulars kite or teardrop-shaped and smooth; prominent gular fold.

Body dorsoventrally compressed, slightly ovoid in dorsal view with widest part ~1.5–2 times wider than neck and pelvis; TrunkL%SVL—0.464 (0.029); 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 keel low.

Limbs covered in elongate kite or teardrop-shaped scales with prominent medium high keels, spine usually protruding beyond distal edge of scale; arms and legs moderately long, ArmL%SVL—0.196 (0.017), LegL%SVL—0.259 (0.020); scales on dorsal surface of upper arm large with keels usually forming lines; 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 4–6 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—1.388 (0.127); 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 4 .

Color and pattern. In life ( Fig. 5 D), ground color light to medium reddish-brown, usually uniform but occasionally with subtle variations in shade forming just discernible blotches; limbs weakly banded; nuchal region dark brown with three pale lines edged with black; lateral surfaces stippled with black; tail with ~10 alternating bands of ground color and pale white, anterior edge of pale bands edged with black, pale bands sometimes joining posteriorly to form an irregular stripe on top of tail; chest and chin sometimes suffused with a light yellow. In preservative, most individuals gray with some reddish hues ( Fig. 13 ); dark upper axillary and dorsolateral zones more apparent; flanks with irregular pale dark flecking forming irregular wavy lines; tail with ~8–10 alternating dark and pale bands, but most individuals with pale bands coalescing to form a pale stripe along posterior half of tail; ventral surfaces pale, some with a reddish hue ( Fig. 12 ).

Habitat. Most collectors’ notes of specimens indicate a preference for cracking clays in the Pilbara region, with one record from a mulga woodland on a clayey loam with small scattered rocks. As mentioned above, this species was combined with T. diabolicus sp. nov. in the PBS analysis (Doughty et al. 2011), which indicated a preference for clay (alluvial) surfaces with strewn rock and tussock grass.

Distribution. Restricted to the Pilbara region of Western Australia. Generally recorded from the Fortescue Marsh area, from near Balfour Downs in the south-east Pilbara, then angling to Millstream-Chichester National Park. There is an outlying record (WAM R160032) from Meentheena Nature Reserve towards the north-east Pilbara, indicating it could be more widely distributed north of the Fortescue River.

Etymology. The specific name is in reference to the Fortescue basin or marsh, formed by the Fortescue River, where this species occurs.

Comparison with other species. Tympanocryptis fortescuensis sp. nov. is mostly likely to be confused with T. cephalus and T. diabolicus sp. nov. It is distinguished from T. cephalus by possessing enlarged dorsal scales in short transverse rows in rows of 2–5 scales (versus 5–7), enlarged row of scales at front of thigh forming a conspicuous ridge (versus weakly-defined row), scales on upper thigh usually aligned, and uniform light reddishbrown dorsum with at most only subtly discernible blotches along midline (versus brown with dark blotches).

Tympanocryptis fortescuensis sp. nov. is distinguished from T. diabolicus sp. nov. by having scales on snout with low keels (versus rugose with feeble keels) and light brown coloration rarely possessing dorsal blotches (versus rich reddish-brown occasionally with blotches).

Remarks. This species is very similar to T. diabolicus sp. nov., differing in coloration and pattern, and having more well-defined keels on the snout. Genetic differences are ~5% between the two taxa (Shoo et al. 2008), and they are geographically separated with T. diabolicus sp. nov. occurring on the uplands of the Hamersley Range, whereas T. fortescuensis sp. nov. occurs on the Fortescue Marsh itself and in cracking clay habitats in the Chichester Range.

Figures

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 12. Holotype of Tympanocryptis fortescuensis sp. nov. (scale bar = 1 cm).

FIGURE 13. Paratypes of Tympanocryptis fortescuensis sp. nov. (scale bar = 1 cm).

Tables

TABLE 4. Summary of meristic (mm) and mensural data for the type series of Tympanocryptis fortescuensis sp. nov.

R# 158076 110129	121974	113625	158074	108817
Sex Male Male	Male	Female	Female	Male
SVL 56.0 50.5	58.0	59.0	49.0	65.0
TrunkL 24.4 22.2	24.6	26.0	23.3	30.7
TailL 78.5 70.0	90.5	92.0	65.5	98.0
HeadL 16.3 15.5	16.8	19.1	15.1	19.4
HeadW 12.1 11.6	13.5	12.3	11.4	14.2
HeadD 8.4 7.6	8.6	8.5	7.4	9.8
SnoutL 4.0 4.0	4.1	4.6	3.9	5.1
SnoutW 5.5 5.6	6.0	6.3	5.5	6.9
EyeL 4.1 3.6	4.4	4.3	3.6	4.7
InterOrb 1.8 1.7	1.9	2.1	2.1	2.3
ArmL 11.8 10.2	10.9	12.3	10.2	11.8
HeadL 7.8 7.9	9.2	9.4	7.8	8.1
LegL 15.5 14.1	14.6	14.3	12.9	16.8
FootL 18.1 16.6	16.3	17.4	14.7	17.8
HeadW/SVL 0.2 0.2	0.2	0.2	0.2	0.2
FootL/SVL 0.3 0.3	0.3	0.3	0.3	0.3
TailL/SVL 1.4 1.4	1.6	1.6	1.3	1.5