Pilbara Death Adder - Acanthopis wellsi
Pilbara death adder Acanthophis wellsi

The Pilbara death adder is a small slender adder very similar in build to the desert death adder Acanthophis pyrrhus. A wellsi can be differentiated by having 19 mid body scales and has undivided prefrontal scales as apposed to A pyrrhus which has 21.

There is however an isolated population of A wellsi at Cape range peninsula near Exmouth that do have divided prefrontals. The body scales on A wellsi are not as keeled as A pyrrhus.

When viewed laterally there is a difference in head shape with A wellsi being of a more even roundness towards the nasal area or front of the head where as A pyrrhus is more arrow shaped. This head shape difference is quite obvious after comparing a few.

There have been individuals found on the edge of their known range that have had strange scale counts or peculiarities. It is though, and likely in my view that these are actually hybrids of both pyrrhus and wellsi.

Coloration varies, but typically they are a reddish body colour with about 40 faint bands of ether light red, yellow brown, and occasionally in rare melanistic individuals black.
The melanistic forms usually show this pigmentation on their upper head scales and can look quite stunning.

There are many specimens that display colour and patterning almost identical to pyrrhus and I believe over the years a lot of reptile keepers without examining these a little closer have automatically assumed that that what they had seen or captured were pyrrhus.

The distribution of this species to some degree, remains uncertain and although generally confined to the Pilbara and a little further south I believe that in many cases amateur reptile enthusiasts have not correctly identified this adder in some areas.

Habitat
The wellsi habitat is typically areas of stony based desert areas surrounded by rocky escarpment scattered throughout with spinifex from which they shelter.

Diet
Their diet consists of small lizards, frogs, and a particular favourite food item is the fat tailed gecko Diplodactylus conspicillatus.  

Breeding
This species has only rarely been bred in captivity. This is simply because at this point of time there are very few specimens in collections and not because they are more difficult to breed than any other adder. Mating in the wild occurs in the wild from about late December to the end of January. As with all adders they bear live young and this occurs in April to May. There has been breeding experiments undertaken with both colour forms e.g. red and the black headed, black banded form to determine whether or not each form produces both colours. Early results have shown that reds will only mate with reds and black headed forms will only mate with black headed forms. I am personally not convinced of this, and believe there are far too few experiment subjects to draw these conclusions. As far as average litter numbers go, I have not seen enough to know, although I suspect that they may have a similar litter size or perhaps slightly less than A pyrrhus.
This is a death adder not commonly kept out side of W.A and I suspect that it will be a few more years yet before these adders are bred in sufficient numbers to become commonly available.