Diporiphora magna Storr, 1974

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 : 43-45

Diporiphora magna Storr, 1974

Common name. Yellow-sided two-lined dragon.

Figure 17 , Tables 3, 4

Diporiphora magna Storr, G.M. 1974 . Agamid lizards of the genera Caimanops , Physignathus and Diporiphora in Western Australia and Northern Territory. Records of the Western Australian Museum 3: 121–146 [137]. Type data: holotype – WAM R42786, Old Lissadell (now submerged by Lake Argyle), WA [16° 30' S, 128° 41' E].

Diagnosis. Body size moderately large (to 77 mm SVL) with very long tail (to 3 × SVL). Gular fold absent, post-auricular and scapular folds strong. Granular scales in axilla, extending over arm but not extending onto sides of neck. 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. Female; 47 mm SVL; 141 mm tail length. Medium Diporiphora , moderately gracile with long limbs and very long tail. One canine on either side of upper jaw. Gular fold absent. Post-auricular and scapular folds strong. Dorsal scales strongly keeled, relatively small and homogeneous. 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. Cluster of spinose scales at back of head on each side, lacks spinose scales on limbs and tail. Granular scales in axilla, extending over arm but not extending onto sides of neck. Ventral scales strongly keeled. Pre-cloacal pores 3 (2 on right; 1 on left); femoral pores 0.

Dorsum strongly patterned. Wide grey vertebral stripe (~2 scales wide at mid-dorsum), extending from back of head onto base of tail, and prominent pale dorsolateral stripes from shoulder to base of tail, fading into background patterning. Seven dark transverse bands between head and pelvis, narrower than the pale background and offset across the vertebral stripe. Head relatively plain with little patterning, labials similar colour to rest of head and lacking pale line between eye and ear. Dark smudge on posterior of tympanum absent. On flanks, granular scales in axilla are dark brown and strongly defined with an abrupt transition to pale flanks with little patterning. Lateral stripe between axilla and groin absent. Dark patch in axilla extending up onto shoulder. Faint banding on hind limbs; dark bands on anterior two-thirds of tail that are wider than the light bands, fading to unbanded light colouration for remainder of tail. Arms and legs with faint dark banding. Ventral surface cream with a few very faint longitudinal stripes on ventral surface of head.

Variation. 54–77 mm SVL; 145–209 mm tail length. Very long tail, ranging from 2.6–3.0 × SVL. Gular fold always absent, post-auricular and scapular strong. In a few individuals, the post-auricular fold, although strong, may be short (<2 mm). Low nuchal crest, more prominent in males. One spinose scale above tympanum and one on post-auricular fold with from 0–3 additional spines on post-auricular fold. Scales rows of dorsolateral stripes on neck and above arms with raised posterior edges. All individuals examined have pre-cloacal pores 4 and femoral pores 0, except for one individual: large male (NMV D73812) from the southern Kimberley has a small indistinct femoral pore on each side.

Variable patterning from strongly patterned individuals to plain individuals. In patterned individuals, 5–7 dark brown transverse bands ranging from narrower to wider than pale interspaces of background colour. Dark bands are often offset to each other on either side of a broad greyish or cream vertebral stripe 3–4 scales wide and two pale dorsolateral stripes usually present. In more plain individuals, dark dorsal transverse bands are faint or absent, vertebral stripe may be absent but with pale dorsolateral stripes from neck to at least level of mid-dorsum. However, dorsolateral stripes are also absent in a few individuals, particularly breeding males. Granular scales in or near the axilla are dark brown, flanks cream, grey, light brown with little patterning. No white markings on face, labial scales speckled with light brown flecks. Faint or no banding on legs. Ventral surface cream, usually plain but some individuals have faint longitudinal stripes in gular region. Males with breeding colouration tend to lose some of their dorsal patterning, having a yellow wash over the head and upper body with a large back patch in axilla that extends onto shoulder.

Distribution and ecology. Diporiphora magna is widely distributed across the tropical savannah region of northern Australia, from the central Kimberley, WA, through the NT and just over the Queensland border at Lawn Hill National Park. It appears to have been replaced by other D. bilineata species group members as follows: to the south by D. lalliae , which occupies the northern deserts, to the west in the Kimberley by D. margaretae and D. gracilis sp. nov., and in the Top End of the NT by D. bilineata , although there is a wide (~ 100 km) area of sympatry between roughly Pine Creek and Katherine.

A habitat generalist occurring in tropical savannah woodlands and grasslands, individuals have been observed to perch on low vegetation, rocks or termite mounds.

Comparison to other species. The distribution of D. magna overlaps with numerous other Diporiphora species across the tropical savannahs of northern Australia. In the Kimberley region, D. magna differs from D. margaretae in having a smaller body size (to 77 vs. 55 mm SVL), stronger post-auricular and scapular folds, a longer tail and flanks lacking speckled appearance (scattered white scales on a dark background). In the northern NT, D. magna differs from D. bilineata in having a post-auricular fold and homogenoous dorsal scales, lacking rows of enlarged vertebral scales and lacking dark flanks with scattered white scales. In the southern part of its range, D. magna can be distinguished from D. lalliae in lacking a gular fold, a longer tail in proportion to body and granular scales in axilla. Across its range, D. magna can be distinguished from D. albilabris , D. bennettii , D. sobria and D. perplexa sp. nov. in lacking a gular fold, lacking femoral pores and having single canines on either side of the upper jaw.

Remarks. Phylogenetic work has redefined the distribution of this species ( Smith et al., 2011). Specimens of D. margaretae were formerly assigned to D. magna , meaning now that D. magna does not occur in the north-west Kimberley region. This taxon is diverse and exhibits morphological variation in colour patterning and overlaps or contacts a number of phylogenetically close species. Where it occurs in close proximity to these species, it can be distinguished on the basis of scalation.

Figures

Figure 17. Diporiphora magna: a, adult male, Larrimah, Northern Territory (photo: S. Wilson); b, holotype WAM R42786, Old Lissadell (now submerged by Lake Argyle), Western Australia.