Unable to see the necessary detail, e.g. mandibles. Proportions and lack of sheen on gaster ('abdomen') suggest a member of the M. pilosula group, rather than M. tarsata.
Thanks Kim. I've added some zoomed in close ups that show the mandibles and a better view of the abdomen. Worse case, I'll go back to the location and see if I can get some better photos.
Hi, I think Kim is right. Myrmecia tarsata has a very shiny gaster (abdomen) while the pilosula group species have a dull gaster due to having a covering of very short hairs (pubescence).