Diporiphora gracilis, 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 : 46-48

Diporiphora gracilis sp. nov.

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

F3BB16E0-259E-4396-AD68-FFE06A0FE624

Common name. Gracile two-lined dragon.

Figure 19 , Tables 3, 4

Holotype. WAM R177291 (formerly NMV D75540 ) (adult male), Fairfield-Leopold Downs Road , south of Gibb River Road, WA (17° 29' 37.0" S, 125° 2' 17.7" E). Collected by P. Oliver on 2 November 2013.

Paratypes. NMV D75541 (adult females), as for holotype ; NMV D73901 (adult male), as for holotype ; WAM R163503 (female) and WAM R163504 (male), Mornington Station , WA (17° 30' 23" S, 126° 02' 07" E) ; WAM R177952 (formerly NMV D75542 ) (adult female), as for holotype .

Diagnosis. Body size moderately long (to 61 mm SVL) with elongate and gracile body shape and very long tail (to 3 × SVL). Gular fold absent, post-auricular and scapular folds weak. Granular scales in axilla, extending over arm to scapular fold. Homogeneous dorsal scales between pale dorsolateral lines that usually lack raised scales in outer row, providing little demarcation between dorsal and lateral scales. Pre-cloacal pores 4; femoral pores 0.

Description of holotype. Male; 57 mm SVL; tail length 165 mm. A medium-sized gracile Diporiphora , with long limbs and a very long tail. One canine on either side of upper jaw. Gular fold absent; post-auricular and scapular folds weak. Dorsal scales on torso strongly keeled, parallel to midline and homogenous; heterogeneous scales on head with wide band of smaller scales across back of head and neck. Low nuchal crest of ~8 scales. Granular scales in axilla, extending over arm to the weak scapular fold. Scales on flanks homogeneous, although changing from small granular scales in axilla to small but non-granular scales on the posterior two-thirds of flanks. Lacks spinose scales on limbs or tail. Ventral scales weakly keeled on head and throat, strongly keeled on body. Pre-cloacal pores 4; femoral pores 0.

Dorsal colour greyish-brown without patterning. Dorsolateral and vertebral stripes absent. Dark transverse bands between head and pelvis absent. Head relatively plain, labials similar colour to rest of head and lacking pale line between eye and ear; lateral portions of snout paler than dorsal surface of snout. Dark smudge on posterior of tympanum absent. Granular scales on axilla dark brown, posterior two-thirds of flanks same colour as dorsal surface. Lateral stripe between axilla and groin absent. Dark patch in axilla, not extending up onto shoulder. Faint banding on hind limbs; tail plain without banding. Arms lack dark banding. Ventral surface cream with no patterning, lower labials faintly stippled. Variation. 52–61 mm SVL; 140–185 mm tail length. Very long tail, ranging from 2.7–3.0 × SVL. Gular fold always absent, post-auricular fold weak or absent, and scapular fold weak. At most, a single small spinose scale above tympanum and one on post-auricular fold. Dorsal scales homogeneous. Presence of outer raised trailing edge of scales on outer row of dorsolateral stripes variable – usually absent in more plain individuals but present in those with strong patterning, providing weak demarcation between dorsal and lateral surface. Gulars smooth. Pre-cloacal pores 4; femoral pores 0.

Variable patterning from strongly patterned individuals to plain individuals. In patterned individuals, dark brown bands offset each other to either side of a broad greyish vertebral stripe, pale well-defined dorsolateral stripes (approximately two scales wide) that extend from back of head to hind legs, where stripes continue as broken stripes down a third of the tail. Dark dorsal cross-bands continue beyond dorsolateral stripes to a narrow pale lateral stripe. Below lateral stripes is plain with start of cream ventral colour. No patterning on head, lacks pale stripe between eye and ear. Faint banding on limbs and banding on anterior third of tail. In plain individuals, there is no patterning on body or head, including no dorsolateral or vertebral stripes. In these plain individuals, granular scales in axilla are dark brown and in life have a well-defined black spot on sides and a greenish-yellow hue to body. No white markings on face, labial scales speckled with light brown flecks. Faint or no banding on limbs. Ventral surface cream, without markings. In life, males with breeding colouration have a well-defined black spot on sides, a greenish-yellow hue to body and a pink flush on the tail.

Etymology. Named for the gracile body shape, with noticeably long and slender body, limbs and tail. Used as a noun in apposition.

Distribution and ecology. Restricted to the south-western Kimberley region (fig. 14). Currently only known from two locations, the type location on the Fairfield-Leopold Downs Road and further east on Mornington Station, approximately 80 km apart.

Diporiphora gracilis sp. nov. appears to be a grassland specialist, occupying savannah grasslands on clay soils associated with the floodplain of the Lennard River. More collecting is required to determine how far the distribution of this species extends and whether it is only associated with grasslands on clay soils.

Comparison with other species. The distribution of D. gracilis sp. nov. overlaps numerous other Diporiphora species. The distribution of D. pindan overlaps with D. gracilis sp. nov. but they appear to occupy different habitats ( D. gracilis sp. nov. in grasslands on floodplains; D. pindan in shrubs and spinifex). Diporiphora pindan can be distinguished from D. gracilis sp. nov., with the latter lacking a well-defined white stripe between eye and ear, having strongly keeled dorsal scales where keels form longitudinal ridges running along torso and having a very long tail in proportion to body size. Differs from D. magna in lacking strong post-auricular and scapular folds, and having a more gracile habitus. Differs from D. lalliae in lacking gular fold and possessing granular scales in axilla. Differs from D. albilabris , D. bennettii , D. sobria and D. perplexa sp. nov. in lacking femoral pores, lacking a gular fold and having single canines on each side of the upper jaw.

Remarks. This species is sister to D. margaretae from the northern Kimberley, both of which form a Kimberley endemic lineage compared to the next closely related species, D. lalliae and D. magna , which both extend across the Kimberley and NT to just inside the Queensland border.

Diporiphora gracilis sp. nov. was first collected on Mornington Station in 2004. The collection of further individuals by J. Melville that had tissues taken establishes this species' distinctiveness, and the morphology of these specimens is shared by the two Mornington specimens.

Figures

Figure 19. Diporiphora gracilis sp. nov. Images of holotype (WAM R177291, formerly NMV D77540), Fairfield-Leopold Downs Road, south of Gibb River Road, Western Australia: a, in life (photo: J. Sumner); b, c, d, dorsal, ventral and, lateral (head) views. Pattern variation (individuals from Mornington Station, Western Australia: e, adult male with breeding colour; f, gravid female (plain); g, gravid female (patterned) (photos: Melissa Bruton, Australian Wildlife Conservancy).