Definitely a Myrmecia, but I don't think it's one of the pilosula-group. This one has a more elongate body and longer legs. It looks a lot like M. tarsata, and could be that species (there are local records, see http://www.antweb.org/description.do?rank=species&name=tarsata&genus=myrmecia ), but then it may be another similar-looking species. More research needed.