Keys to the Pheidole cervicornis group workers

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This worker key is based on: Sarnat E. M., Fischer, G. and E.P. Economo. 2016. Inordinate spinescence: taxonomic revision and microtomography of the Pheidole cervicornis species group (Hymenoptera, Formicidae). PLoS ONE. 11:e0156709. doi:10.1371/journal.pone.0156709

There is a key to major workers, followed by a key to minor workers.

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major workers (major worker of Pheidole cervicornis unknown)


  • Posterolateral lobes with glossy corners, free of sculpture; lateral and ventral portion of lobes also glossy. Clypeus lacking strong median carina. First gastral tergite entirely glossy. Color uniformly dark reddish brown . . . . . Pheidole drogon
  • Corners of posterolateral lobes shining, but covered with very fine carinulae or striae. Clypeus with strong median carina. First gastral tergite with some portion either shagreened or striate, but not entirely glossy. Color variable . . . . . 2


return to couplet #1

  • Head carinulae arcuate from anterior clypeal border to frons, converging towards median impression of posterolateral lobes. Carinulae of posterolateral lobes distinctly transverse. Mandible with striations limited to posterolateral portion. Propodeal spines either downcurved or upturned apically. Basal third of first gastral tergite shagreened to weakly striate. Color variable; some populations uniformly dark reddish brown and others with a yellowish brown mesosoma . . . . . Pheidole barumtaun
  • Head with carinulae longitudinal fromanterior clypeal border to frons, then diverging laterally and becoming more fine. Head carinulae of posterolateral lobes arcuate. Mandible entirely striate. Propodeal spines becoming downcurved apically. Entire first gastral tergite longitudinally striate. Color uniformly yellowish brown . . . . . Pheidole viserion

Minor workers


  • Pronotal armament begins as thick basal trunk that diverges into two long anterolaterally

pointed prongs. Head and mesosoma sculptured with thick crenulated rugulae. Head more circular (CI 94–101) . . . . . Pheidole cervicornis

  • Pronotal spines simple and non-branching. All surfaces glossy, free of sculpture. Head more ovoid (CI 84–91) . . . . . 2mi


return to couplet #1mi

  • Color uniformly shining yellow. Smaller (HW 0.62–0.68 mm). Antennal scapes relatively longer (SI 162–169) . . . . . Pheidole viserion
  • Color variable, but never uniformly shining yellow. Larger (HW 0.67–80 mm). Antennal scapes relatively shorter (SI 135–165) . . . . . 3mi


return to couplet #2mi

  • Antennal scapes relatively longer (SI 146–165). Head narrower (CI 84–90). Legs longer (FL 1.22–1.38mm). Color either uniformly reddish-brown, or tricolored with reddish-brown head and gaster and contrasting brownish-yellow mesosoma . . . . . Pheidole barumtaun
  • Antennal scapes relatively shorter (SI 135–141). Head more circular (CI 89–91). Legs shorter (FL 1.07–1.16 mm). Color uniformly reddish-black . . . . . Pheidole drogon