Key to West Palaearctic Strumigenys (as Pyramica)

This worker key is based on: *Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028.

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Strumigenys

Note. Reliance on antennomere count has been responsible for misidentifications in the regional fauna; it is not used in the following key. The number of antennal segments has traditionally been used to separate argioia (4 segments) from the remaining West Palaearctic species (6 segments). However, specimens of Strumigenys baudueri, Strumigenys tenuipilis and Strumigenys tenuissima often have funicular segments 2 and 3 partially to entirely fused, and these together are sometimes partially or mostly fused to funicular segment 4. In some samples the antenna therefore appears 6-segmented, in others 5-segmented and in extreme cases 4-segmented.

1

 * Mandibles linear, elongate and narrow, MI 35-40. At full closure mandibles engage only at their extreme apices and enclose a large open space between them; labral lobes visible between mandibles even at full closure. Tooth at dorsal apex of mandible very long and spiniform, strongly crossing over the tooth from the opposite mandible when closed. Cephalic dorsum with small orbicular hairs present. (Germany, France, Switzerland, Italy, Hungary, Greece, Croatia, Azerbaijan, Georgia, Tunisia) . . . . . Strumigenys argiola


 * Mandibles short and triangular, MI 15-20. At full closure mandibles engage throughout their visible length, without a large open space between them; labral lobes not visible when mandibles fully closed. Tooth at apex of mandible small and inconspicuous, not spiniform, not strongly crossing over the tooth from the opposite mandible when closed. Cephalic dorsum without orbicular hairs . . . . . 2

2
return to couplet #1
 * Pronotal humerus without a projecting hair; pronotum dorsolaterally with sharp raised margination. Dorsal alitrunk and first gastral tergite without standing hairs. Leading edge of scape with 1-2 hairs near the subbasal bend that are distinctly curved toward the scape base. Dorsal surface of mandible basally with a very distinct transverse sharp edge or rim that extends across its width, parallel to and in front of the anterior clypeal margin. CI 84-90, SI 51-57. (Cosmopolitan tramp species) . . . . . Strumigenys membranifera


 * Pronotal humerus with a projecting simple hair; pronotum dorsolaterally without sharp raised margination. Dorsal alitrunk and first gastral tergite with standing hairs. Leading edge of scape with all hairs curved or inclined toward the scape apex. Dorsal surface of mandible basally without a transverse sharp edge or rim running across its width. CI 66-72, SI 69-76 . . . . . 3

3
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 * Dorsum of clypeus in full-face view densely clothed with conspicuous broadly spatulate to spoon-shaped hairs; in profile these hairs parallel with the surface from which they arise and closely applied. Medially curved ground-pilosity bordering the upper scrobe margins distinctly spatulate. (Spain, France, Switzerland, Italy, Hungary, Croatia, Greece, Turkey, Armenia, Tunisia, Morocco) . . . . . Strumigenys baudueri


 * Dorsum of clypeus in full-face view clothed with slender hairs that are very narrowly spatulate or simple and cylindrical; in profile these hairs markedly elevated and either arched or inclined anteriorly. Medially curved ground-pilosity bordering the upper scrobe margins fine and simple . . . . . 4

4
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 * Hairs on clypeal dorsum narrowly spatulate; in profile the hairs distinctly anteriorly curved or anteriorly arched. (France, Italy, Greece) . . . . . Strumigenys tenuipilis


 * Hairs on clypeal dorsum simple, fine and cylindrical throughout their length and tapered or truncated apically; in profile the hairs mostly straight, inclined anteriorly. (France (Corsica), Greece) . . . . . Strumigenys tenuissima