The Golden-tailed Spiny Ant, Polyrhachis ammon, is one of several spiny ants with a bright golden gaster. The mesosoma has only one pair of strong spines at the rear. This species is common in open forest and woodland in coastal eastern Australia from north Queensland to Victoria.

Most species of Polyrhachis have large spines on their bodies, from which they get their common name. There are well over 100 Australian species of spiny ants. They are quite large and often attractive ants that forage on the ground and run up and down the trunks of trees during the day. However a number of species are strictly nocturnal.

Most are black, but many have parts of their bodies, particularly the abdomen, covered in a thick layer of silver or golden hairs.

All species of Polyrhachis are monomorphic, meaning that all the workers in a nest are similar in size. They have a waist made up of a single segment, which often has spines. Most species also have spines on the mesosoma. The first segment of the gaster is long and usually covers at least half its length. Spiny ants, like most sugar ants, do not have a metapleural gland, and lack an opening just above the base of the hind legs.