Polyrhachis gravis

Polyrhachis gravis is a characteristic species of the dry, mulga and spinifex clad country of the central Australia. It has been collected in the Pilbara region in Western Australia and across the Northern Territory to western Queensland (Kohout, 2013).

Identification
In spite of being widely distributed, P. gravis is relatively morphologically uniform with only minor variations from the types detected in some specimens from Western Australia and Queensland. These are manifest mostly in the direction of the body sculpturation, the apical width of the propodeal dorsum and the length of the dorsal petiolar spines that can vary even in specimens of a single nest series (e.g. specimens from Kunoth Pdk, nr Alice Springs).

Distribution based on Regional Taxon Lists
Australasian Region: Australia.

Castes
Sexuals and immature stages unknown.

Nomenclature

 *  gravis. Polyrhachis (Campomyrma) gravis Clark, 1930c: 15, fig. 1 (w.) AUSTRALIA.

Worker
Kohout (2013) - (holotype cited first, paratype second): TL c. 10.58, 8.77, 8:12-10.58; HL 2.43, 2.25, 2.18-2.48; HW 2.17, 1.93, 1.93-220; CI 89, 86, 86-92; SL 274, 2.53, 2.49-2.81; SI 126, 131, 125-131; PW 1.72, 1.56, 1.56-1.72; MTL 3.28, 3.09, 3.09-3.38 (1 +1 +14 measured).

Type Material


Kohout (2013) - Based on the original description, it appears that both available specimens of P. gravis were regarded by Clark as equals, i.e. syntypes. However, one of the specimens is furnished with a red tag which reads: T-6238, Type. When Dr Robert W. Taylor examined both specimens, he evidently considered this specimen to be the holotype and added a new red tag reading ‘HOLOTYPE, T-6238, Polyrhachis gravis Clark’. I am following Taylor’s decision and accept this specimen as the holotype of P. gravis, with the second specimen labelled with ‘PARATYPE, T-9088’ on a blue tag, considered a paratype.