[2] The fossil, which was preserved in Baltic amber from the Eocene, was formally described in Mayr's journal article Die Ameisen des baltischen Bernsteins, designating it as the type species by monotypy (the condition of a taxonomic group having only a single taxon described) for the newly established genus Prionomyrmex.

British myrmecologist Horace Donisthorpe would also retain the genus in Ponerinae without explanation, but William Brown Jr. would return it to Myrmeciinae in 1954.

[7] Prior to this, John S. Clark, the original author who described Nothomyrmecia, noted that the genus was similar in appearance to Prionomyrmex; both the heads and mandibles were identical, but the nodes were different.

[9] This classification was short-lived, as Nothomyrmecia was separated and treated as a valid genus from Prionomyrmex by Dlussky & Perfilieva in 2003, on the base of the fusion of an abdominal segment.

[10] Other studies published in the same year came to the same conclusions of Dlussky & Perfilieva, and the subfamily Prionomyrmecinae would later be treated as a tribe in Myrmeciinae.

[11] However, Baroni Urbani would treat the tribe as a subfamily again in both his 2005 and 2008 publications, suggesting additional evidence in favor of his former interpretation as opposed to that of Ward and Brady's arguments.

This subsequent report that described new fossil myrmecines accepted the classification of Archibald et al. and Ward & Brady without comment on the views of Baroni Urbani.

[14][18] P. janzeni was described by Cesare Baroni Urbani of the University of Basel, Switzerland in 2000, based on two specimens preserved in Baltic amber from Kaliningrad, Russia.

[7] The estimated body length is 13 millimetres (0.51 in) long with an elongated head, and large oval-shaped eyes are present.

The estimated body length of P. longiceps is 12 to 14 millimetres (0.47 to 0.55 in) long, with a thick petiole and large propodeal teeth.

[4][6] Wheeler (1915) described a male P. longiceps, commenting that the head is short but broad with very large eyes while the mandibles are small and far apart.

[4] P. wappleri was described in 2012 by Russian palaeoentomologist Gennady M. Dlussky of the Moscow State University, from a fossilised holotype worker found in Germany from the Aquitanian stage 29 to 30 million years ago.

[14] The estimated body length of P. wappleri is 14 millimetres (0.55 in) long, and the head is 1.35 times longer than the total width of it.

[17] Workers may have not recruited nest mates to food sources or lay down pheromone trails, as these ants were solitary hunters.