Key to New World Solenopsis Species Complexes

AntWiki: The Ants --- Online

The following key is based on Pacheco, J.A. & Mackay, W.P. 2013. The systematics and biology of the New World thief ants of the genus Solenopsis (Hymenoptera: Formicidae). Edwin Mellen Press, Lewiston, New York. 501 pp. PDF

Note, the geminata species complex is included for ease of identification and to avoid confusion, as they are commonly found.

You may also be interested in

1

  • Second and usually third segment of funiculus at least 1 ~ times as long as broad . . . . . geminata species complex (former subgenus Solenopsis, fire ants and Labauchena)
  • Second and at least third segment of funiculus only slightly longer than broad, usually broader than long (Fig. 5) . . . . . 2

2

return to couplet #1

  • Eyes of worker with fewer than 12 ommatidia, usually fewer than 6 . . . . . 4

3

return to couplet #2

  • Postpetiole not greatly dilated, scale-like . . . . . nigella species complex (former subgenus Euophthalma in part)

4

return to couplet #2

  • Clypeus of minor workers usually bicarinate (occasionally lacking carinae) with clypeal carina turning medially from anterior margin of clypeus, anterior clypeal margin of minor worker lacking teeth (major workers with 4 to 5 teeth); female with 10-11 segmented antennae . . . . . wasmannii species complex (former subgenus Diagyne and includes Carebarella bicolor)
  • Clypeus of minor workers bicarinate, carinae diverge anteriorly and always present, clypeal teeth always present, but may be poorly developed; female with II-segmented antenna; widely distributed throughout New World . . . . . 5 (former subgenus Diplorhoptrum, thief ants)

5

return to couplet #4

  • Eye tiny and difficult to see, postpetiole circular viewed dorsally; head elongate and typically coarsely punctured . . . . . pygmaea species complex
  • Eye small, but easily seen (Fig. 7), usually consisting of about 4 (rarely more) ommatidia; without all of the above characteristics . . . . . 6

6

return to couplet #5

  • Scape short (typically less than 0.24 mm), minor segments of funiculus short (about 0.07 mm); petiole thickened as seen in profile. . . . . brevicornis species complex
  • Scape longer (typically longer than 0.24 mm), minor segments of funiculus long (typically> 0.70 mm), if shorter, petiole narrow as seen in profile . . . . . 7

7

return to couplet #6

  • Petiole very wide, apex of node forming extensive arch viewed laterally much wider than postpetiole . . . . . stricta species complex
  • Petiole approximately as wide as postpetiole (typically slightly wider) than postpetiole, apex of node acute, triangular viewed laterally . . . . . 8

8

return to couplet #7

  • Punctures on dorsum of head usually small, barely perceptible; extralateral clypeal teeth poorly developed; head somewhat elongate (CI 83-85) . . . . . molesta species complex
  • Punctures on head coarse, much wider than hairs arising from them; extralateral teeth typically well developed (at least in majority of nest series); head nearly quadrate (CI 85-92) . . . . . fugax species complex