Key to Australian Polyrhachis (Myrmothrinax) species

The following key to Australian Polyrhachis (Myrmothrinax) species (based on the worker caste) is modified from Kohout (2012 ).

1

 * Generally reddish-brown; propodeal spines mostly upturned; petiolar node relatively slim, narrowed dorsally; petiolar dorsum in lateral view forming a single continuous line with dorsoposteriorly elevated median spine => Polyrhachis delicata
 * Generally black or very dark reddish brown; propodeal spines distinctly less elevated, oblique; petiolar node in lateral view distinctly thicker; petiolar dorsum virtually flat with leading edge of median spine more steeply elevated => Polyrhachis queenslandica