Key to Polyrhachis gravis species-group workers

AntWiki: The Ants --- Online

This worker key is based on: 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

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1

  • Dorsum of petiole armed with a pair of spines . . . . . 3

2

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  • Pronotal humeri simply angular; eyes smaller, distinctly convex; dorsal petiolar spine long and acute . . . . . Polyrhachis pseudothrinax
  • Pronotal humeri produced into short, distinct teeth; eyes larger, only moderately convex; dorsal petiolar spine short and blunt . . . . . Polyrhachis unicornis

3

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Polyrhachis bispinosa side.jpg
  • Petiolar node in profile slender, scale-like . . . . . 4

4

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  • Pilosity generally long, hair-like, rather abundant . . . . . 5

5

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

6

return to couplet #4

  • Petiole high and slender in frontal view; dorsolateral margins steeply raised, strongly converging dorsally, forming single base for two slender dorsal spines; body black, somewhat semipolished, 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; body rather dull black, opaque, with appendages black or dark reddish-brown . . . . . 7

7

return to couplet #6

  • Dorsal petiolar spines tooth-like, distinctly shorter and stouter than lateral spines; bristle-like pubescence very sparse, virtually lacking from dorsum of mesosoma and petiole . . . . . Polyrhachis curtospinosa
Polyrhachis curtospinosa side.jpg
  • Dorsal petiolar spines slender, distinctly longer than lateral spines; bristle-like pubescence present on most body surfaces, including dorsum of mesosoma and petiole . . . . . 8

8

return to couplet #7

  • 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

9

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  • 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