Urodacus novaehollandiae

Scientific Name: Urodacus novaehollandiae Peters 1861
Size: 70-100mm
Ecomorphotype: Fossorial-Obligate burrower

Description: A member of the endemic Australian Urodacidae family, whose closest relatives include members of the Scorpionidae inc., Heterometrus, Opisthophthalmus, and Pandinus.

A reasonably large robust scorpion, with well-developed metasomal carinae and spines. A sand comb is present, but with much fewer setae compared to that of U. yaschenkoi. Tarsal claws are equal in length on all feet. Cheliceral teeth show a lack of secondary serrations.

Found predominantly along the coast this species digs meandering burrows of varying depth depending on the soil and its moisture content. Distribution ranges from beaches just north of Adelaide, South Australia, across the Great Australian Bight to coastal areas around Perth, Western Australia. It’s similar in many respects to U. yaschenkoi - the burrow entrance is often most recognisable by excavated soil spread around in a fan shape outside the burrow entrance. In South Australia, it can be found burrowing in coastal shellgrit soils running parallel to the beach line, or higher up on coastal cliffs. The burrow has the same 3 basic components, entrance chamber, spiral section and terminal chamber as U. yaschenkoi. Unlike U. yaschenkoi the burrow meanders more, and is wider spread in the spiral section, this may be due to the loose nature of the shellgrit soils it burrows in. I have not investigated the burrow structure in other soil types where it may not meander.

A Species Complex
There are a number of forms under this species name, at least two in SA and at least one in WA. In SA the form found along beaches north of Adelaide and at least along the east coast of the Yorke Peninsula is quite different to that found at the foot of York Peninsula, which is a lot more like the typical forms around the Perth coastal regions. This scorpion can (but not always) have a distinct two-tone appearance where the carapace and pedipalps are often a dark reddish/brown colour with the rest of the scorpion being a lighter brown. More than likely the WA and SA forms will be different species as there are some distinctive differences between them. There is another undescribed two-tone species found in the Perth region which is sometimes confused with this species, the latter is not a coastal species. Other more uniform yellowish forms are also found. Future DNA work should help to differentiate this species complex into valid species.

Reference:

Koch, L. E. 1977. The taxonomy, geographic distribution and evolutionary radiation of Australo-Papuan scorpions. Records of the Western Australian Museum 5 (2):83-367.