Diporiphora sobria 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 : 39-40

Diporiphora sobria Storr, 1974

Common name. Northern savannah two-pored dragon.

Figure 13 , Tables 3, 4

Diporiphora albilabris sobria 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 [135]. Type data: holotype – WAM R23180, Pine Creek, NT [14° 04' S, 131° 58' E].

Diporiphora bennettii arnhemica 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 ANWC R740, near upper Katherine River, NT [14° 13' S, 132° 36' E]. Synonymy decision of current work.

Diagnosis. Body size moderately large (to 69 mm SVL) with moderately long tail (2.3–2.6 × SVL). Gular fold present, post-auricular fold strong and scapular fold present but often weak. Dorsolateral stripes present. Lacks dark smudge on posterior edge of tympanum. In WA, the scales between dorsolateral stripes are homogeneous (fig. 10b); in the NT, heterogeneous (fig. 10c). Pre-cloacal pores 4; femoral pores 2.

Description of holotype. Subadult, unknown sex; 34 mm SVL; 68 mm tail length. Moderately robust with long limbs and tail. Two canines on either side of upper jaw. Gular fold present, scapular and post-auricular folds present but weak. Dorsal scales homogeneous between faint pale dorsolateral stripes. These homogeneous scales are relatively large and strongly keeled. On the outer sides of the faint dorsolateral stripes are smaller keeled scales. Scales on flanks homogeneous, with keels running parallel to dorsum. Lacks spinose scales on head, limbs or tail. Lacks granular scales in axilla. Ventral scales homogenous and strongly keeled. Pre-cloacal pores 4; femoral pores 2.

Dorsal colour uniform brown and grey tones, without apparent patterning. Lacks vertebral stripe but has faint dorsolateral stripes on anterior half of body, fading to background colour midway down torso. Lacks visible dark transverse bands between head and pelvis. Head relatively unpatterned: labials pale; and very faint, narrow pale line from posterior of eye to above ear. Dark smudge on posterior of tympanum absent. Flanks unpatterned and consistent with dorsal colouration. Lateral stripe between axilla and groin absent. Lacks lateral dark patch. Arms lack dark banding. Very faint banding on hind limbs; dark bands on anterior two-thirds of tail, with dark bands being narrower than the light, fading to unbanded for remainder of tail. Ventral surface of head, torso and tail unpatterned and white or cream colouration.

Variation. 46–69 mm SVL; 114–162 mm tail length. Tail long, ranging from 2.3–2.6 × SVL. Gular fold always present and often strong, post-auricular fold from weak to strong and scapular fold present but variable. No low nuchal crest. Most individuals have homogeneous dorsal scales between pale dorsolateral stripes, with all individuals examined from WA having homogeneous scales. However, animals examined from the eastern NT, on the Barkly Tablelands and the Gulf of Carpentaria region, and from north-central regions, such as the Mt Wells and Pine Creek area, had somewhat heterogeneous scales between pale dorsolateral stripes. In these animals, paravertebral rows on either side of the vertebral scale row are not reduced in size in comparison to the vertebral scale row, but the 2nd paravertebral scale row is slightly enlarged, with a strong central keel that is aligned to the scales immediately anterior and posterior. These strongly keeled scales that are aligned form a ridge running along the dorsum either side of the midline. Animals with these dorsal scales include NMV D72666–68, D72706, D72707, D72715, D72720, D73995, D74001, D74003, D74022, D74024 and D74262. Scales on the sides are similar to typically sized dorsal scales and are angled up towards midline. Ventral scales homogenous and strongly keeled. Pre-cloacal pores 4 (occasionally up to 5); femoral pores 2 (occasionally 3 or 4).

Dorsal patterning variable from plain to strongly patterned. Strongly patterned individuals, typically adult females and juveniles, have approximately 7–9 irregular dark transverse bands from nape to legs across dorsum on a pale background. Dark bands are of similar width or narrower than pale background. These bands are separated by an indistinct faint grey or light brown vertebral stripe. The dark transverse bands continue laterally beyond the pale cream dorsolateral stripes, becoming diffuse and terminating on sides, with defined lateral stripe absent. Labial scales pale cream, with a few darker flecks, extending as a broad pale band along jaw to back of head ending at the post-auricular fold. In these animals, the lateral surfaces of the neck, axilla and flanks lack a defined dark patch. Some individuals are less strongly patterned, particularly in the NT, and lack the pale dorsolateral stripes or the dorsolateral stripes fade midway down dorsum. Adult males in breeding colouration often have little patterning, having strongly contrasting charcoal black, white and chestnut or orange-red colouring on head, flanks and upper body, with tail also having a pink flush in some individuals. Arms and legs banded. Ventral surface of head, torso and tail usually unpatterned and white or cream colouration. However, adult males may have up to three pairs of grey stripes in gular region, terminating at gular fold.

Distribution and ecology. Widely distributed from the southern Kimberley region (i.e. south of the barrier ranges: King Leopold and Durack), Top End of the NT (but with no records from Arnhem Land) and just extending into western Queensland (fig. 8). Extends south to the Katherine area.

A habitat generalist occurring in tropical savannah woodlands and grasslands, within these habitats it appears to be associated with rockier areas. Similar habitats to D. albilabris . Seen to perch on low vegetation, rocks or termite mounds.

Comparison with other species. This species has a very wide distribution and overlaps with numerous other Diporiphora species. In WA, it can be distinguished from D. albilabris in having a scapular fold, fewer spines around tympanum and post-auricular fold and having homogenous scales between the dorsolateral stripes. It differs from D. perplexa sp. nov. in having pale rows of dorsolateral scales, usually a strong post-auricular fold, two femoral pores and lacks dark markings on the posterior of the tympanum. Differs from D. bilineata , D. magna and D. lalliae in having femoral pores, two pairs of canines in upper jaw and white labial scales. It also differs from D. bilineata , D. magna and D. margaretae in having a gular fold and two pairs of canine teeth on each side of upper jaw.

Remarks. This species incorporates what was D. arnhemica and much of the distribution of D. albilabris albilabris sensu lato. Despite the original name, this species does not appear to occur in Arnhem Land from our observations, although collections from this region are scarce. This taxon is diverse and exhibits morphological variation in dorsal scalation. Where it occurs near the morphologically similar D. albilabris in the Kimberley region, the homogeneous dorsal scalation differs and separates the two species.

Figures

Figure 13.Diporiphora sobria: a, adult male with breeding colouration, Halls Creek, Western Australia (photo: S. Wilson); b, holotype WAM R23180 from Pine Creek, Northern Terrotory.