What was that Myrmidon of Mystery?
As so astutely guess by commentator JasonC (who really ought to write a book about how to identify insects on the internet), the ant was Pachycondyla lutea. Ten points, Mr. Jason.
I’m going to award two points to Dave, also, for noting the taxonomic troubles that surround Pachycondyla. Yesterday’s was an especially hard mystery, and those of you who guessed Hypoponera were not far off.
The trouble is that Pachycondyla isn’t a natural grouping of ants. It’s just an arbitrary assemblage of ponerines, the assorted odds and ends left over after the recognition of more distinct genera (like Hypoponera, Leptogenys and Odontomachus). The genus doesn’t have a distinct look- you just kind of have to know the species. Pachycondyla lutea is a relatively common- if inconspicuous- Australian ant with a unique combination of eye size, body shape, and a distinct set of long hairs on the clypeus.