Pseudonaja inframacula, (WAITE, 1925)

Skinner, Adam, 2009, A multivariate morphometric analysis and systematic review of Pseudonaja (Serpentes, Elapidae, Hydrophiinae), Zoological Journal of the Linnean Society 155 (1), pp. 171-197 : 189-192

PSEUDONAJA INFRAMACULA (WAITE, 1925)

Demansia textilis inframacula Waite, 1925: 26 . Syntypes, not found; type locality, northern end of Coffin Bay Peninsula, South Australia.

Diagnosis: Pseudonaja inframacula may be distinguished from the remaining species of Pseudonaja redescribed here in exhibiting a medium to dark grey venter (very occasionally, only the throat is dark grey in specimens from Yorke Peninsula) and a diploid chromosome number of 36. The relative length of the prefrontal suture (i.e. the length of the prefrontal suture divided by head length) and the relative distance from the rostral to the frontal are consistently higher than for P. nuchalis specimens (0.078 –0.125 vs. 0.050 –0.070 and 0.143 –0.195 vs. 0.096 –0.124, respectively; see Table 9). Pseudonaja inframacula usually has fewer ventrals than P. affinis and P. aspidorhyncha .

classes, and sex chromosomes that differ considerably in size.

Distribution: Southern Eyre Peninsula and southern Yorke Peninsula; geographically isolated populations occur near Nullarbor Station, west of Eyre Peninsula and on the North Neptunes and Wardang Island, Spencer Gulf ( Fig. 13 ).

Description: Ventrals 194–208; subcaudals 55–66; snout appears rounded from dorsal perspective; nasal undivided (81 of 84 cases) or divided (three cases), contacting preocular; two (79 of 84 cases) or three (five cases) postoculars; parietal contacting (79 of 84 cases) or separated from (five cases) lower postocular (or mid postocular where three postoculars are present); six supralabials; seven infralabials; temporals 1 + 2 + 3 (58 of 83 cases), 1 + 2 + 4 (15 cases), 2 + 2 + 4 (three cases), 1 + 3 + 3 (two cases), 1 + 3 + 4 (two cases), 2 + 3 + 4 (two cases) or 2 + 2 + 3 (one case); 4–9 nuchals contacting parietals; dorsals in 21–25 rows at first ventral, 17–19 rows one head length posterior to occiput, 17 rows midbody, 13–15 rows one head length anterior to vent, 15–17 rows at last ventral; anal divided (37 of 42 cases) or undivided (five cases); snout–vent length 457–1188 mm; tail length 89–238 mm, 16.099 –24.909 % of snout–vent length.

Dorsum light to very dark brown; numerous dark brown or black scales often scattered on body, concentrated dorsomedially in many specimens; some specimens possess a series of black bands, each tapering laterally from 2–4 dorsals to one dorsal in width, along body; darker brown or black blotches commonly present on head; venter of nearly all specimens medium to dark grey; ventrals often exhibit a contrasting pale to medium brown or lighter grey sectorial marking laterally (see Fig. 12 ); chin commonly cream; buccal epithelium whitish to pale grey (preserved specimens); iris dark with pale yellowish grey to orange ring around pupil.

Mengden (1985) and Skinner et al. (2005) reported a diploid chromosome number of 36, with autosome pairs 4–17 being separable into two distinct size

PSEUDONAJA MENGDENI WELLS & WELLINGTON, 1985

Pseudonaja mengdeni Wells & Wellington, 1985: 48 . Holotype, NTM R1989 ; type locality, 2 km east of Maryvale , Northern Territory.

Pseudonaja kellyi Wells & Wellington, 1985: 48 . Holotype, NTM R1689 ; type locality, Stuart Highway, 160 km north of Erldunda , Northern Territory.

Diagnosis: Pseudonaja mengdeni may be differentiated from the remaining species of Pseudonaja redescribed here except P. nuchalis in exhibiting a predominantly black (as opposed to flesh pink) buccal epithelium (in preserved specimens, the buccal epithelium is dark bluish grey, rather than whitish to pale grey). All specimens are separable from P. inframacula , P. nuchalis and P. textilis (also P. guttata , P. ingrami and P. modesta ; see Mengden, 1985) on the basis of diploid chromosome number, while at least some specimens possess fewer chromosomes than P. affinis and P. aspidorhyncha (see Skinner et al., 2005, and below). Pseudonaja mengdeni typically exhibits fewer dorsal rows at the level of the first ventral and one head length posterior to the occiput than P. nuchalis ; these species are often also differentiable on the basis of the shape of the snout (rounded in P. mengdeni , as opposed to chisel shaped in P. nuchalis ).

Description: Ventrals 193–224; subcaudals 49–64; snout appears rounded from dorsal perspective; nasal undivided (93 of 97 cases) or partially divided (four cases), contacting preocular; two (96 of 98 cases) or three (two cases) postoculars; parietal contacting (97 of 98 cases) or separated from (one case) lower postocular (or mid postocular where three postoculars are present); six supralabials; seven (96 of 98 cases) or eight (two cases) infralabials; temporals 1 + 2 + 3 (95 of 96 cases) or 1 + 2 + 4 (one case); 5–8 nuchals contacting parietals; dorsals in 19–24 rows at first ventral, 17–19 rows one head length posterior to occiput, 17 rows midbody, 13–15 rows one head length anterior to vent, 13–17 rows at last ventral; anal divided; snout–vent length 322–1077 mm; tail length 51–206 mm, 15.779 –22.991 % of snout–vent length.

Almost all specimens may be referred unambiguously to one of two distinct colour forms, these corresponding to the ‘Orange with black head’ and ‘Pale head, grey nape’ morphs described by Mengden (1985). Among the 49 specimens examined, the ‘Orange with black head’ morph is represented by 15 specimens, and the ‘Pale head, grey nape’ morph by 31 specimens (three specimens could not be assigned to either morph). A series of ten specimens collected from Alice Springs during a 2-week period (SAMA R56714-6, 56718-25) includes six ‘Orange with black head’ and four ‘Pale head, grey nape’ individuals. Specimens that could be considered intermediates of these colour forms were not observed (see, however, Bush, 1989b).

‘Orange with black head’ specimens exhibit pale to dark yellow or orange dorsal coloration, typically with a fine to heavy, black reticulated pattern (absent anteriorly in many specimens); rarely, a series of broad, dark brown bands is present on body; head and neck dark brown or black; venter cream or yellow, often with subtle to conspicuous orange, salmon, dark brown, or grey spots; in many specimens, there is a darker brown blotch on the posterior margin of each ventral laterally; chin and throat cream, dark grey, or black; buccal epithelium predominantly dark bluish grey (preserved specimens) or black (live specimens); iris dark with reddish orange ring around pupil.

‘Pale head, grey nape’ specimens display pale to medium brown or yellowish brown dorsal coloration, commonly with a fine, black reticulated pattern (often evident only laterally and posteriorly); indistinct pattern of greyish brown, oblique bands, approximately two dorsals wide, occasionally discernible (usually more pronounced laterally and posteriorly); some specimens exhibit a pattern of broad, dark brown bands with interposed narrower bands along body; typically, a broad, darker brown or greyish brown band is present on neck, often bordered anteriorly by several black scales (these may compose a chevron); head and neck (anterior to nucal band) pale to light brown; frontal, supraoculars and subocular (i.e. 3rd and 4th) supralabials commonly darker brown; venter cream or yellow, often with subtle to conspicuous orange, salmon or grey spots; many specimens exhibit a darker brown blotch on the posterior margin of each ventral laterally; chin cream; buccal epithelium predominantly dark bluish grey (preserved specimens) or black (live specimens); iris dark with reddish orange ring around pupil.

Three specimens that could not be assigned unequivocally to either the ‘Orange with black head’ morph or the ‘Pale head, grey nape’ morph exhibit similar coloration; the dorsum is dark brown, the snout is slightly lighter brown and the venter is cream or yellow with a brown sectorial marking on each ventral laterally.

Mengden (1985) reported substantially different karyotypes for the ‘Orange with black head’ and ‘Pale head, grey nape’ morphs, the former exhibiting a diploid chromosome number of 32, with a gradual decrease in the size of autosome pairs 4–15, and sex chromosomes that are of equal size, and the latter displaying a diploid number of 34, with autosome pairs 4–16 being separable into two distinct size classes, and sex chromosomes that differ considerably in size. However, Skinner et al. (2005) found no consistent karyotypic differences between the morphs, with two ‘Orange with black head’ specimens and three ‘Pale head, grey nape’ specimens exhibiting Mengden’s ‘Orange with black head’ karyotype (possible causes of this discrepancy are discussed by Skinner et al., 2005).

Distribution: Western and central Australia, from Carnarvon, Western Australia, to Mootwingee National Park, western New South Wales ( Fig. 14 ).

Figures

Figure 12. Pseudonaja inframacula (SAMA R38606), ventrolateral perspective of midbody illustrating contrasting sectorial markings on ventrals laterally.

Figure 13. Geographical distribution of Pseudonaja inframacula specimens examined in this study (closed circles) and/or included in Skinner et al.’s (2005) phylogenetic analysis (open circles represent specimens not included in the morphometric analyses). Codes for geographical groups correspond with those in Table 2.

Figure 14. Geographical distribution of Pseudonaja mengdeni specimens examined in this study (closed circles) and/or included in Skinner et al.’s (2005) phylogenetic analysis (open circles represent specimens not included in the morphometric analyses). Codes for geographical groups correspond with those in Table 2.