Diporiphora perplexa, MELVILLE & DATE & HORNER & Doughty, 2019

MELVILLE, JANE, DATE, KATIE SMITH, HORNER, PAUL & Doughty, Paul, 2019, Taxonomic revision of dragon lizards in the genus Diporiphora (Reptilia: Agamidae) from the Australian monsoonal tropics, Memoirs of Museum Victoria 78, pp. 23-55 : 37-39

Diporiphora perplexa sp. nov.

ZooBank LSID: http://zoobank.org/ urn:lsid:zoobank.org:act:

4A6A3A8B-5FB1-40D5-843B-258D095238F3

Common name. Kimberley rock dragon.

Figure 12 , Tables 3, 4

Holotype. WAM R177290 (formerly NMV D73819 ) (adult male), Gibb River Rodd , 20 km west of Ellenbrae Station, WA (15° 57.31' S, 126° 52.9' E). Collected by J. Melville on 9 September 2005.

Paratypes. NMV D73805 (adult female), Home Valley Station , WA (15° 44.39' S, 127° 49.83' E) ; NMV D73841 (adult female), King Edward River Campground, Mitchell Plateau Road, WA (14° 56' 57.1" S, 126° 12' 10.4" E) ; NMV D73978 (adult male), Buchanan Highway, south of Jasper Creek , NT (16° 02' 46.8" S, 130° 51' 49.3" E) ; NMV D73980 (adult female), Bullo Road off Victoria Highway, NT (15° 48' 39.2" S, 129° 40' 13.5" E) ; WAM 119719 (male), Emma Gorge, Cockburn Range, WA (15° 50' S, 128° 02' E) ; WAM R162517 (female), 25 km S Wyndham , WA (15.7154° S, 128.2684° E) ; WAM R171418 (male), Prince Regent River National Park , WA ; WAM R175785 (female), Waterfall Yard , 15 km N Mt Elizabeth Homestead, WA (16.2822° S, 126.1059° E) .

Diagnosis. Body size moderately large (to 68 mm SVL) with long tail (1.9–2.5 × SVL). Gular and scapular folds present but weak; post-auricular fold strong. Homogeneous dorsal scales. Pale dorsolateral stripes from back of head to one-third down torso. Black smudge on posterior edge of tympanum, extending on to scales posterior to tympanum. Pre-cloacal pores 2–4; femoral pores 0.

Description of holotype. Male; 63 mm SVL; 140 mm tail length. Moderately stout with long tail and limbs. Two canines on either side of upper jaw, with posterior canines extremely enlarged relative to anterior canines. Gular fold present but weak. Strong post-auricular fold, weak scapular fold. Dorsal scales homogeneous, strongly keeled with keels parallel to midline forming lines running longitudinally down dorsum from shoulders to base of the tail; enlarged scales associated with vertebral or dorsolateral stripes not conspicuous. Scales on flanks homogeneous, with keels on posterior flanks angled towards dorsum. Lacks spinose scales on head, limbs and tail. Scales in axilla small but not granular. Ventral scales weakly keeled in gular region and strongly keeled on body. Pre-cloacal pores 2; femoral pores 0.

Dorsum patterning faint. Lacks vertebral stripe and faint dorsolateral stripes from back of head to one-third down torso. Lacks visible dark transverse bands between head and pelvis. Head relatively unpatterned: labials same colour as rest of head; and faint, narrow pale line from posterior of eye to above ear. Prominent black smudge on posterior edge of tympanum, extending onto scales behind ear. Flanks have large dark patches in axillary region extending up onto shoulder, then extending posteriorly and fading to dark speckled appearance on a pale background. Lateral stripe between axilla and groin absent. Large lateral dark patch in axilla, extending up onto shoulder. Arms lack dark banding. Very faint banding on hind limbs and tail, with light bands much wider than darker bands. Ventral surface plain cream to white.

Variation. 48–76 mm SVL; 101–183 mm tail length. Tail long, ranging from 1.9–2.5 × SVL. In some individuals keeling on dorsal scales converge towards the midline approximately halfway down torso but run parallel to midline from mid-dorsum to pelvis. Usually a single spinose scale above tympanum, with 1–3 spines on post-auricular fold, occasionally with a short row of spines extending from post-auricular fold to above tympanum. Dorsolateral scale rows raised on neck. In some individuals, a slightly raised nuchal crest (males) and the scales of dorsolateral rows on body appear to be enlarged with slightly thickened keels, but this is barely perceptible (hence, we have not included it as a diagnostic character). Pre-cloacal pores were usually 2, but many had 4; no specimens with femoral pores.

Dorsal colouration variable from strongly patterned (mainly smaller individuals and females) to unpatterned (adult males). Most individuals have pale dorsolateral stripes running from the back of the head to at least a third of the way down the torso. In strongly patterned individuals, these stripes continue onto the tail where they converge approximately halfway down. More patterned individuals have 5–7 dark cross-bands between the pale dorsolateral stripes, continuing onto the tail. These cross-bands are intersected by a narrow pale white, cream or grey vertebral stripe. Also, these individuals will often have a black patch on shoulder, into the axilla, with pale flecks. Individuals with little patterning are usually adult males with breeding colours, which includes a large black patch in axillary region extending up onto shoulder, then posteriorly fading to dark speckled appearance with a bright yellow background, and a pink flush on tail and rear legs. No distinct patterning on head, upper labials flecked with light brown and cream, with no pale labial stripe. Ventral surfaces plain cream to white. Gular region plain or with diffuse brown speckling (no lines).

Distribution and ecology. Widespread in the Kimberley and extreme western Top End of the NT. They occur from the Yampi Peninsula in the south-western Kimberley, extending eastwards to the Kununurra area and to the western NT in the Jasper Gorge area.

This species is almost always associated with rocks. It will also climb onto vegetation, such as cane grass, small shrubs and trees, spinifex and even pandanus and mangroves, but with rocks or creek lines nearby.

Etymology. Named from the Latin for confused or cryptic, in reference to Allan Greer’s (former curator at the AMS) thoughts on this species when carrying out earlier work on the group in the 1990s. This species remained hidden until a genetic analysis and consultation of the D. bennettii type with its small body size, short tail and diffuse pale patterning.

Comparison with other species. Similar to D. bennettii , occurring in similar rocky habitats, but differs in having a long tail and limbs and dorsolateral stripes. Can be distinguished from D. albilabris and D. sobria in mostly lacking femoral pores, having no white or pale stripes on the head (on upper labials or between eye and ear), no stripes under chin and homogenous dorsal scales. Differs from D. magna , D. margaretae and D. pindan in having a gular fold, a black spot on tympanum and two canine teeth on each side of upper jaw. Diporiphora lalliae differs from D. perplexa sp. nov. in lacking both a black spot on tympanum and double canine teeth on each side of upper jaw.

Remarks. This species has previously been confused with D. bennettii (see account above), and this is the species usually depicted in field guides as D. bennettii . However, both genetic work and examination of the original specimens have now distinguished these two species. Interestingly, D. perplexa sp. nov. is the only member of the D. bennettii species group that is sympatric with the three other species (which are generally allopatric). This distributional pattern suggests that D. perplexa sp. nov. may have different habitat preferences and ecology to the other species that allows for sympatry.

Recent unpublished phylogenomic research using singlenucleotide polymorphisms shows that D. perplexa sp. nov. is highly divergent and genetically distinguishable from the D. sobria (as defined below), even in areas of syntopy (J. Fenker, unpublished data).

Figures

Figure 12. Holotype of Diporiphora perplexa sp. nov. (WAM R177290, formerly NMV D73819): a, in life – adult male in breeding colouration from Gibb River Road, west of Ellenbrae Station, Western Australia; b, c, d, preserved specimen in dorsal, ventral and lateral (head) views. Yellow arrow highlights a key diagnostic character: dark pigment “smear” on posterior of tympanum spreading onto neighbouring head scales (photos: J. Melville).