Pseudonaja nuchalis, GUNTHER, 1872

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 : 193-196

PSEUDONAJA NUCHALIS GÜNTHER, 1872

Pseudonaja nuchalis Günther, 1858: 227 . Lectotype, BMNH, 1946.1.20.41; type locality, Port Essington , Northern Territory.

Pseudelaps bancrofti De Vis, 1911: 25 . Holotype, QM J187 ; type locality, Stannary Hills , Queensland.

Pseudonaja imperitor Wells & Wellington, 1985: 48 . Holotype, NTM R3352 ; type locality, Groote Eylandt , Northern Territory.

Pseudonaja jukesi Wells & Wellington, 1985: 48 . Holotype, NTM R1186 ; type locality, Oenpelli , Northern Territory.

Pseudonaja vanderstraateni Wells & Wellington, 1985: 49 . Holotype, NTM R0371 ; type locality, Stuart Highway, 161 km north of Katherine , Northern Territory.

Diagnosis: Pseudonaja nuchalis may be differentiated from the remaining species of Pseudonaja in displaying a diploid chromosome number of 30. This species also differs from P. affinis , P. aspidorhyncha , P. inframacula and P. textilis 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), and is often separable from P. affinis , P. inframacula , P. mengdeni and P. textilis in possessing a strap-like rostral that imparts a chisel shape to the snout from a dorsal perspective. 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. inframacula and P. textilis specimens (0.050 –0.070 vs. 0.078 –0.136; see Table 9), while the relative distance from the rostral to the frontal is consistently lower than for P. inframacula specimens (0.096 –0.124 vs. 0.143 –0.195; see Table 9). Pseudonaja nuchalis typically exhibits a greater number of dorsal rows one head length posterior to the occiput than the remaining species of Pseudonaja redescribed here, and fewer ventrals than P. affinis and P. aspidorhyncha .

Description: Ventrals 194–207; subcaudals 57–66; snout appears rounded to (more usually) chisel shaped from dorsal perspective; nasal undivided, contacting preocular; two postoculars; parietal contacting lower postocular; six (18 of 19 cases) or seven (one case) supralabials; seven infralabials; temporals 1 + 2 + 3 (14 of 19 cases), 1 + 2 + 4 (one case), 1 + 3 + 3 (one case), 1 + 3 + 4 (one case), 2 + 2 + 3 (one case) or 2 + 3 + 3 (one case); 5–9 nuchals contacting parietals; dorsals in 23–27 rows at first ventral, 19–23 rows one head length posterior to occiput, 17 rows midbody, 14–15 rows one head length anterior to vent, 15–17 rows at last ventral; anal divided; snout–vent length 245–1116 mm; tail length 48–224 mm, 17.229 –20.072 % of snout–vent length.

Dorsum light to medium brown; occasionally with a series of indistinct to distinct, broad, darker brown bands along body; scattered dark brown or black scales on neck; in many specimens the frontal, supraoculars and occiput are darker brown; snout pale brown, often contrasting with darker posterior region of head; head and neck of some specimens dark brown or black; venter cream or pale yellow, commonly with subtle to conspicuous salmon spots (usually more evident anteriorly); ventrals typically with a brown or greyish brown sectorial marking laterally; chin cream; buccal epithelium predominantly dark bluish grey (preserved specimens) or black (live specimens); iris dark with orange ring around pupil.

Mengden (1985) and Skinner et al. (2005) reported a diploid chromosome number of 30, with a gradual decrease in the size of autosome pairs 4–14, and sex chromosomes that are of approximately equal size.

Distribution: Tropical Northern Territory, north of 17°S ( Fig. 15 ). The holotype of Pseudelaps bancrofti (a synonym of Pseudonaja nuchalis ; see above) was collected from Stannary Hills, northern Queensland, intimating that P. nuchalis occurs more extensively in northern Australia than indicated by Figure 18.

Notes: Although none of the specimens listed in Appendix S1 displays a black head and neck as observed in the lectotype of Pseudonaja nuchalis and the holotype of Pseudonaja vanderstraateni , mitochondrial DNA sequences recently obtained for three specimens exhibiting a black head and neck (all collected from tropical northern Australia) are identical or nearly identical to those for typical P. nuchalis ‘Darwin’ specimens (R. Foster, pers. comm.).

Skinner et al. (2005: 568) reported that ‘specimens composing the P. nuchalis ‘Darwin’ clade exhibit an elevated number of scale rows at the level of the first ventral relative to other textilis group specimens (19–23 vs. 17–19 rows)’; this should have read ‘specimens composing the P. nuchalis ‘Darwin’ clade exhibit an elevated number of scale rows one head length posterior to the occiput...’.

PSEUDONAJA TEXTILIS (DUMÉRIL, BIBRON & DUMÉRIL, 1854)

Furina textilis Duméril, Bibron & Duméril, 1854: 1242 . Holotype, MNHP 3944 (not found; Cogger et al., 1983); type locality, Australia.

Pseudoelaps superciliosus Fischer, 1856: 107 . Holotype, ZMH 362 ; type locality, Sydney , New South Wales.

Demansia annulata Günther, 1858: 213 . Holotype, BMNH, 1946.1.17.54; type locality, Australia.

P[seudoelaps] kubingii Jan, 1859: 127. Holotype, Pesth (Budapest), presumed lost or destroyed ( Cogger et al., 1983); type locality, New South Wales.

P[seudoelaps] sordellii Jan, 1859: 127. Holotype, MSNM not found ( Cogger et al., 1983); type locality, Australia.

Cacophis guntheri Steindachner, 1867: 91 . Holotype, not found ( Cogger et al., 1983); type locality, Australia. Pseudoelaps beckeri Jan & Sordelli, 1873 , plate 4, figure 2. Holotype, ZMH not found ( Cogger et al., 1983); type locality, Sydney, New South Wales.

Furina bicucullata McCoy, 1879: 13 . Lectotype, NMV D1832 ; type locality, Longwood , Victoria.

Pseudechis cupreus (in part) Boulenger, 1896: 329. No types; description based on literature records ( Cogger et al., 1983).

Pseudonaja ohnoi Wells & Wellington, 1985: 48 . Holotype, NTM R1970 ; type locality, Alice Springs , Northern Territory.

Diagnosis: Pseudonaja textilis may be differentiated from the remaining species of Pseudonaja in exhibiting a diploid chromosome number of 38. The relative length of the prefrontal suture (i.e. the length of the prefrontal suture divided by head length) is consistently higher than for P. aspidorhyncha and P. nuchalis specimens (0.096 –0.136 vs. 0.049 –0.092; see Table 9). Ventral coloration serves to distinguish P. textilis from P. affinis and P. inframacula ; whereas the latter two species display either a contrasting dark grey or brown throat or an entirely dark brown or grey venter (see above), the venter in P. textilis is dirty cream to yellow (grading to brown or greyish brown posteriorly in some specimens), without contrasting throat coloration (although there are often conspicuous dark grey, medium to dark brown, or orange spots anteriorly). Pseudonaja textilis is separable from P. mengdeni and P. nuchalis in exhibiting a flesh pink (as opposed to a predominantly black) buccal epithelium (in preserved specimens, the buccal epithelium is whitish to pale grey, rather than dark bluish grey).

Description: Ventrals 192–231; subcaudals 57–72; snout appears rounded from dorsal perspective; nasal undivided (94 of 99 cases) or partially divided (five cases), contacting preocular; two (97 of 99 cases) or three (two cases) postoculars; parietal contacting (62 of 99 cases) or separated from (37 cases) lower postocular (or mid postocular where three postoculars are present); six supralabials; seven (96 of 100 cases) or eight (four cases) infralabials; temporals 1 + 2 + 3 (86 of 95 cases), 1 + 2 + 4 (six cases), 1 + 3 + 3 (two cases) or 1 + 2 + 5 (one case); 3–8 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, 14–17 rows at last ventral; anal divided; snout–vent length 535– 1415 mm; tail length 115–273 mm, 18.705 –24.856 % of snout–vent length.

Dorsum pale to dark brown; pigment often concentrated in posterior region of dorsals; occasionally, there are (very few) scattered darker brown scales on body; a broad, darker brown band is rarely present on neck; venter dirty cream to yellow, grading to brown or greyish brown posteriorly in some specimens; very often with conspicuous dark grey, medium to dark brown, or orange ventral spots (usually more evident anteriorly); ventrals occasionally exhibit a brown or greyish brown sectorial marking laterally; posterior margins of ventrals of many specimens dark brown; chin cream; buccal epithelium whitish to pale grey (preserved specimens) or flesh pink (live specimens; Gillam, 1979); iris dark with pale yellowish brown to orange ring around pupil.

Mengden (1985) and Skinner et al. (2005) reported a diploid chromosome number of 38, with autosome pairs 4–18 being separable into two distinct size classes, and sex chromosomes that are of approximately equal size.

Distribution: Eastern Australia, from near Malanda, northern Queensland, to Yorke Peninsula; putatively isolated populations occur on the Barkly Tableland and in the MacDonnell Ranges; also present in southern New Guinea ( Fig. 16 ).

Figures

Figure 15. Geographical distribution of Pseudonaja nuchalis 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 16. Geographical distribution of Pseudonaja textilis 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). Skinner et al.’s (2005) analysis also included two specimens from Merauke, West Papua (not shown). Codes for geographical groups correspond with those in Table 2.