AN EXTENDED DESCRIPTION OF THE PILBARA DEATH ADDER, ACANTHOPHIS WELLSI HOSER (SERPENTES ELAPIDAE), WITH NOTES ON THE DESERT DEATH ADDER, A. PYRRHUS BOULENGER, AND IDENTIFICATION OF A POSSIBLE HYBRID ZONE

WA Museum Records and Supplements | Updated 1 decade ago

Abstract - An extended description is provided for the Pilbara Death Adder, Acanthophis wellsi, based on material from throughout the Pilbara region and adjacent Cape Range Peninsula, Western Australia. Acanthophis wellsi was formerly confused with the Desert Death Adder, A. pyrrhus, but differs from this highly distinctive species in features of head scalation and hemipenial morphology as well as meristic parameters. Possible hybrids between the two species are identified from the Giralia - Cane River area where their distributions interdigitate. Several populations of A. wellsi show a striking pattern polymorphism involving melanism of the head and transverse body bands.

A pilot genetic analysis of a small number of individuals suggests that all of the species of Acanthophis are closely related. Acanthophis wellsi appears to be closest genetically to A. pyrrhus, but this may not denote a special cladistic affinity. A cladistic analysis of morphological characters identifies A. wellsi as a relatively plesiomorphic species, perhaps' closest in overall body form to the common ancestor of all Acanthaphis species.