Key to Australian Polyrhachis (Campomyrma) species

AntWiki - Where Ant Biologists Share Their Knowledge
Jump to navigation Jump to search

The following key to Australian Polyrhachis (Campomyrma) species (based on the worker caste) is currently incomplete. It contains keys for the gravis and micans groups (Kohout, 2013[1]) and the hexacantha complex (Kohout, 2012[2]).

Key to workers of P. gravis group


  • Dorsum of petiole armed with single spine => 2
  • Dorsum of petiole armed with pair of spines => 3


  • Pronotal humeri simply angular; eyes smaller, distinctly convex; dorsal petiolar spine long and acute (Fig. 5B,E-F) => Polyrhachis pseudothrinax
  • Pronotal humeri produced into short, distinct teeth; eyes larger, only moderately convex; dorsal petiolar spine short and blunt (Fig. 5D,G-H) => Polyrhachis unicornis


  • Petiolar node in profile distinctly swollen at base (Fig. 1F) => Polyrhachis bispinosa
  • Petiolar node in profile slender, scale-like (e.g. Figs 1H; 3H) => 4


  • Pilosity generally long, hair-like, rather abundant => 5
  • Pilosity generally short, bristle-like, less abundant => 6


  • Large species (HL 2.68); pilosity very long, abundant; lateral margins of propodeal dorsum barrel-shaped (VIC) => Polyrhachis captiva
  • Smaller species (HL < 2.50); pilosity shorter, more sparse, notably on dorsum of mesosoma; lateral margins of propodeal dorsum converging posteriorly (WA) => Polyrhachis capillata


  • Petiole high and slender in frontal view; dorsolateral margins steeply raised, strongly converging dorsally, forming single base for two slender dorsal spines (Fig. 4D,G); body black, somewhat semi-polished, with appendages light orange (WA, Kimberley) => Polyrhachis palmerae
  • Petiole about as long as wide in frontal view; dorsolateral margins less steep and less strongly converging dorsally; bases of dorsal pair of spines more widely separated (e.g. Figs 2D; 4B); body rather dull black, opaque, with appendages black or dark reddish-brown => 7


  • Dorsal petiolar spines tooth-like, distinctly shorter and stouter than lateral spines (Fig. 2D); bristle-like pubescence very sparse, virtually lacking from dorsum of mesosoma and petiole => Polyrhachis curtospinosa
  • Dorsal petiolar spines slender, distinctly longer than lateral spines (e.g. Figs 3B,D; 4B); bristle-like pubescence present on most body surfaces, including dorsum of mesosoma and petiole => 8


  • Anterior margin of first gastral tergite with strongly raised carina => 9
  • Anterior margin of first gastral tergite with only poorly indicated carina (WA) => Polyrhachis opacita


  • Antennal scapes longer (SI >125); eyes more-or-less normal, moderately convex; pronotal humeri narrowly rounded with pronotal margins behind shallowly emarginated; greatest width of pronotal dorsum at middle of segment (NT, QLD) => Polyrhachis gravis
  • Antennal scapes shorter (SI 115); eyes distinctly smaller, strongly convex; pronotal humeri distinctly angular; greatest width of pronotal dorsum across humeri (WA) => Polyrhachis hespera

Key to workers of P. hexacantha complex


  • Smaller species (HL < 1.81); lateral petiolar spines only weakly divergent in dorsal view, forming a continuous line with sides of petiolar node (Fig.

2) => Polyrhachis smithersi

  • Larger species (HL > 1.95); lateral petiolar spines widely divergent, strongly extending laterally before curving posteriorly (e.g. Fig. 9) => 2



  • Dorsum of mesosoma very finely and somewhat longitudinally striate; sculpturation of head distinctly finer, semipolished; intercalary spines of petiole only moderately long (Figs 6-7) => Polyrhachis fuscipes
  • Dorsum of mesosoma regularly reticulate-punctate, opaque; intercalary spines of petiole distinctly longer (Figs 9, 11-12) => Polyrhachis hexacantha

Key to workers of P. micans group


  • Petiole with four, almost subequal spines => 2
  • Petiole with two large dorsal spines; lateral spines greatly reduced or obsolete => 3


  • Petiole with dorsal margin strongly raised dorsomedially towards closely approximated dorsal spines (Fig. 6B, E); propodeal teeth rather massive, long and broad (Fig. 46); legs medium reddish-brown => Polyrhachis eureka
  • Petiole with dorsal margin less strongly raised; dorsal spines situated further apart (Fig. 7B); propodeal spines relatively short, more acute and slender (Fig. 7F); legs very dark reddish-brown or black => Polyrhachis micans


  • Body distinctly reddish-brown; lateral petiolar spines reduced to short acute teeth (NT, QLD) => Polyrhachis incerta
  • Body uniformly black; lateral petiolar spines reduced to blunt angles, or obsolete => 3


  • Propodeal dorsum very narrow, about 1.5 times longer than basal width, with parallel lateral margins; dorsal petiolar spines long and slender (WA, NT, QLD) => Polyrhachis prometheus
  • Propodeal dorsum distinctly wider than long, with strongly posteriorly converging lateral margins; dorsal petiolar spines relatively short (QLD) => Polyrhachis shattucki


  1. Kohout, R.J. 2013. A review of the Polyrhachis gravis and micans species-groups of the subgenus Campomyrma Wheeler (Hymenoptera: Formicidae: Formicinae). Memoirs of the Queensland Museum, Nature 56, 92-117.
  2. Kohout, R. 2012. A new species of the subgenus Campomyrma Wheeler of the genus Polyrhachis Fr. Smith from the Australian Capital Territory (Hymenoptera: Formicidae: Formicinae). Australian Entomologist 39, 321-329.