Pseudonaja aspidorhyncha, (MCCOY, 1879)

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 : 187-189

PSEUDONAJA ASPIDORHYNCHA (MCCOY, 1879)

Diemenia aspidorhyncha McCoy, 1879: 13 . Holotype, NMV D12352; type locality, restricted to junction of Murray River and Darling River , Victoria, by Coventry (1970).

Diemenia carinata Longman, 1915: 31 . Holotype, QM J1508 ; type locality, Cane Grass Station, via Charleville , Queensland.

Demansia acutirostris Mitchell, 1951: 547 . Holotype, SAMA R3133 ; type locality, Lake Eyre , South Australia.

Pseudonaja gowi Wells, 2002: 6 . Holotype, designated as ‘the largest specimen of this species from the vicinity of Lyndhurst, SA in the South Australian Museum collection’ ( Wells, 2002: 6); type locality, Lyndhurst, South Australia.

Diagnosis: Pseudonaja aspidorhyncha may be differentiated from the remaining species of Pseudonaja redescribed here except P. nuchalis in possessing a strap-like rostral that imparts a chisel shape to the snout from a dorsal perspective (see Fig. 1 ). A diploid chromosome number of 34 serves to distinguish P. aspidorhyncha from the remaining species of Pseudonaja except P. affinis and possibly P. mengdeni (see Skinner et al., 2005, and below). The relative length of the prefrontal suture (i.e. the length of the prefrontal suture divided by head length) is consistently lower than for P. textilis specimens (0.049 –0.092 vs. 0.096 –0.136; see Table 9). Pseudonaja aspidorhyncha is separable from P. mengdeni and P. nuchalis in displaying (when preserved) a whitish to pale grey (as opposed to predominantly dark bluish grey) buccal epithelium (in live specimens, the buccal epithelium is never black as in P. mengdeni and P. nuchalis ), and usually exhibits a greater number of ventrals than P. inframacula and P. nuchalis .

Description: Ventrals 207–226; subcaudals 47–63; rostral strap like, snout appearing chisel shaped from dorsal perspective; nasal undivided, contacting preocular; two postoculars; parietal contacting (64 of 72 cases) or separated from (eight cases) lower postocular; six (70 of 72 cases) or five (two cases) supralabials; seven (71 of 72 cases) or eight (one case) infralabials; temporals 1 + 2 + 3 (61 of 71 cases), 1 + 2 + 4 (eight cases), 1 + 3 + 3 (one case) or 2 + 2 + 4 (one case); 5–8 nuchals contacting parietals; dorsals in 21–27 rows at first ventral, 17–20 rows one head length posterior to occiput, 17 rows midbody, 13–15 rows one head length anterior to vent, 14–18 rows at last ventral; anal divided (35 of 36 cases) or undivided (one case); snout– vent length 341–1276 mm; tail length 49–199 mm, 12.618 –18.862 % of snout–vent length.

Dorsum pale to medium brown; indistinct pattern of darker brown or greyish brown, oblique bands, approximately one dorsal in width, often evident (usually more pronounced laterally and posteriorly); some specimens exhibit a series of indistinct to distinct, broad, darker brown or black bands along body, occasionally with interposed narrower bands; not uncommonly, a broad, dark brown or black band is present on neck; body and neck commonly with scattered dark brown or black scales; frontal, supraoculars and subocular (i.e. 3rd and 4th) supralabials often darker brown; occasionally, entire head dark brown; venter dirty cream or yellow, or medium brown; ventrals commonly exhibit a darker brown sectorial marking laterally; posterior margins of ventrals of some specimens darker brown; chin typically cream or pale yellow; buccal epithelium whitish to pale grey (preserved specimens); iris dark with light orange ring around pupil.

Mengden (1985) reported a diploid chromosome number of 34, with autosome pairs 4–16 being separable into two distinct size classes, and sex chromosomes that are of equal size.

Distribution: Southern central Australia, south of 27°S, from Penong, western Eyre Peninsula, to Hermidale, central New South Wales ( Fig. 11 ).

Notes: Wells (2002: 6) erected the name Pseudonaja gowi for Mengden’s (1985) ‘Southern with black nuchal band’ morph. As discussed by Skinner et al. (2005: 569), specimens of this morph are part of P. nuchalis ‘Southern’, so that the name gowi is a junior synonym of aspidorhyncha .

Figures

Figure 1. Pseudonaja aspidorhyncha (SAMA R18600), dorsal perspective of head (left); P. mengdeni (SAMA R20981), dorsal perspective of head (right); see Table 1 for abbreviations.

Figure 11. Geographical distribution of Pseudonaja aspidorhyncha 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.