Key to Neotropical and Nearctic Strumigenys

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

Bolton noted in regards to this key: Strumigenys precava and Strumigenys silvestrii are keyed twice as their intercalary dentition varies from a single small denticle to absent.

This key is from a study that included the now synonymized genus Pyramica. Therefore there are two sets of keys that treat two sets of Strumigenys species. The species of the Neotropics were split among three keys: the key found below, a key to the Nearctic Pyramica and a key to the Neotropical Pyramica.

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 * Strumigenys

1

 * Antenna with 4 segments; the first funicular segment followed directly by the 2-segmented club . . . . . 2


 * Antenna with 5 or usually 6 segments; the first funicular segment separated from the 2-segmented club rarely by one, usually by two, much smaller segments . . . . . 3

2
return to couplet #1
 * Ventral surface of petiole with a spongiform strip or curtain. Leading edge of scape with all hairs curved or inclined toward the apex of the scape. Dorsum of head and promesonotum with scale-like to orbicular hairs. Mandible with a spiniform preapical tooth. (Pantropical tramp species) . . . . . Strumigenys emmae


 * Ventral surface of petiole without spongiform tissue. Leading edge of scape with one to several hairs that distinctly curve toward the base of the scape. Dorsum of head and promesonotum with fine simple hairs. Mandible with 2 minute preapical denticles that are extremely small and difficult to see, under low magnifications appearing edentate. (Brazil) . . . . . Strumigenys quadrua

3
return to couplet #1
 * Leading edge of scape with all hairs curved or inclined toward the apex of the scape; without hairs that curve toward the base of the scape, without a series of hairs at right-angles to the long axis of the scape shaft . . . . . 4 4


 * Leading edge of scape either with one to many hairs that distinctly curve toward the base of the scape, or rarely with hairs that are at right-angles to the long axis of the scape shaft; never with all hairs obviously curved or inclined toward the apex of the scape . . . . . 37

4
return to couplet #3
 * Mandible without intercalary teeth or denticles that arise between the apicodorsal and apicoventral teeth of the apical fork, nor arise from the dorsal base of the apicoventral tooth . . . . . 5


 * Mandible with 1 or 2 intercalary teeth or denticles that arise between the apicodorsal and apicoventral teeth of the apical fork, or arise from the dorsal base of the apicoventral tooth . . . . . 10

5
return to couplet #4
 * Ventrolateral margin of head with a strongly developed preocular notch immediately in front of the eye, anterior portion of eye detached from side of head. Mandible with 2 distinct acute preapical teeth, both in the distal third of the length; proximal preapical tooth longer than the distal. (Cosmopolitan tramp species) . . . . . Strumigenys rogeri


 * Ventrolateral margin of head straight to shallowly concave in front of the eye but without a preocular notch, anterior portion of eye not detached from side of head. Mandible with a single preapical tooth or with a distal tooth and a minute proximal denticle located near the midlength . . . . . 6

6
return to couplet #5
 * First gastral tergite dorsolaterally sharply marginate throughout its length. Propodeal declivity with a broad spongiform lamella. (Costa Rica, Panama, Venezuela, Colombia) . . . . . Strumigenys marginiventris


 * First gastral tergite without dorsolateral margination. Propodeal declivity with a narrow carina . . . . . 7

7
return to couplet #6
 * Postpetiole sculptured across entire disc. First gastral tergite with sculpture present other than basigastral costulae . . . . . 8


 * Postpetiole smooth across most or all of disc. First gastral tergite smooth except for basigastral costulae . . . . . 9

8
return to couplet #7
 * Petiole with a narrow ventral spongiform crest. Disc of postpetiole longitudinally costulate. First gastral tergite finely and densely longitudinally striolate-costulate for half or more of its length. Hairs on first gastral tergite long and flagellate, very fine. Mandible with a preapical tooth, without an additional minute denticle just proximal of midlength. (Venezuela, Colombia, Peru, Bolivia) . . . . . Strumigenys interfectiva


 * Petiole without trace of ventral spongiform tissue. Disc of postpetiole reticulate-punctate. First gastral tergite superficially reticulate-punctate posterior to basigastral costulae. Hairs on first gastral tergite short and curved, simple to weakly remiform. Mandible with a preapical tooth and additionally with a minute denticle, that may be difficult to see, just proximal of midlength. (Mexico) . . . . . Strumigenys manis