Key to Neotropical 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.

Bolton noted in regards to this key: Note: The position in the key of Strumigenys xenognatha, known only from the queen, is conjectural. The two Dominican Amber fossil species, 'Strumigenys electrina and 'Strumigenys schleeorum, are omitted from the key.

This key is from a study that included the now synonymized genus Pyramica. Therefore there are two sets of keys for the Strumigenys species from the Neotropical region: the key found below for the group of species once classified as Pyramica and a key Key to Neotropical and Nearctic Strumigenys.

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 * Strumigenys

1

 * Antenna with 4 segments; first funicular segment not separated from the 2-segmented apical club . . . . . 2


 * Antenna with 6 segments; first funicular segment separated from the 2-segmented apical club by two small segments . . . . . 3

2
return to couplet #1
 * Anterior clypeal margin convex in full-face view; lateral margins of clypeus without projecting hairs of any form. Outer margins of fully closed mandibles intersect anterior clypeal margin at the clypeal anterolateral angles. Pronotum marginate dorsolaterally. (Brazil) . . . . . Strumigenys minuscula


 * Anterior clypeal margin broadly concave in full-face view; lateral margins of clypeus with short freely laterally projecting hairs. Outer margins of fully closed mandibles intersect anterior clypeal margin mesad of the clypeal anterolateral angles. Pronotal dorsum rounding broadly into the sides. (Cuba) . . . . . Strumigenys simulans

3
return to couplet #1
 * Mandibles in full-face view sublinear to linear, elongate and narrow; at full closure engaging only in the apical halves or less of their lengths; either with an elongate space between the mandibles or their inner margins convex so that the margins touch, or nearly touch, near the midlength . . . . . 4


 * Mandibles in full-face view either short and stoutly trap-like, or triangular to elongate-triangular; at full closure engaging through most or all of their exposed length, without a space between the mandibles or at most with a diastema basally between basal lamella and first (basal) tooth . . . . . 31

4
return to couplet #3
 * Ventral surface of petiole with a strip or curtain of spongiform tissue. Leading edge of scape without freely projecting broadly spatulate or spoon-shaped hairs, without hairs that are curved toward the base of the scape . . . . . 5


 * Ventral surface of petiole without spongiform tissue. Leading edge of scape with freely projecting spatulate to spoon-shaped hairs, usually at least one curved toward the base of the scape but sometimes all directed anteriorly or curved toward apex of scape . . . . . 7

5
return to couplet #4
 * Antennal scrobe absent. A single preapical denticle present on inner margin of mandible, close to apicodorsal tooth. Dorsolateral margin of head and pronotal humeri without specialised elongate or flagellate hairs. Dorsal surfaces of head, alitrunk and first gastral tergite without standing pilosity of any form. Bulla of metapleural gland almost reaching annulus of propodeal spiracle. (Costa Rica) . . . . . Strumigenys warditeras


 * Antennal scrobe present. More than one preapical teeth or denticles present on inner margin of mandible. Dorsolateral margin of head and pro notal humeri with specialised elongate or flagellate hairs. Dorsal surfaces of head, alitrunk and first gastral tergite with standing pilosity present. Bulla of metapleural gland very small, widely separated from annulus of propodeal spiracle . . . . . 6

6
return to couplet #5
 * Cuticle on side of head within the antennal scrobe smooth and shining. Lateral margin of preocular carina not visible in full-face view. Basalmost preapical tooth on mandible arising proximal of the midlength of the blade. Labrum apically broadly bilobate, the lobes expanding distally. Dorsal surfaces of head and alitrunk smooth and shining. (Bahamas, Cuba) . . . . . Strumigenys nitens


 * Cuticle on side of head within the antennal scrobe reticulate-punctate. Lateral margin of preocular carina visible in full-face view. Basalmost preapical tooth on mandible arising distal of the midlength of the blade. Labrum apically narrowly biconical, the lobes tapering distally. Dorsal surfaces of head and alitrunk reticulate-punctate. (Venezuela, Brazil, Paraguay) . . . . . Strumigenys tanymastax

7
return to couplet #4
 * Disc of postpetiole smooth or with weak longitudinal costulae in parts, never densely reticulate-punctate . . . . . 8


 * Disc of postpetiole densely reticulate-punctate over most or all of its surface . . . . . 12

8
return to couplet #7
 * Cephalic dorsum with 2 pairs of filiform standing hairs, one pair near highest point of vertex, the other near the occipital margin. Apicoscrobal and pronotal humeral hairs narrow, filiform. Apical fork of mandible with 2 intercalary denticles that arise from the ventral surface of the apicodorsal tooth, near its base . . . . . 9


 * Cephalic dorsum with a single pair of stoutly remiform standing hairs, located close to the occipital margin. Apicoscrobal and pronotal humeral hairs thick, remiform. Apical fork of mandible with 2 intercalary denticles that arise from the vertical surface between the apicodorsal and apicoventral teeth. (Venezuela, Colombia) . . . . . Strumigenys nubila

9
return to couplet #8
 * Mandible with 2 preapical teeth or denticles. (Colombia) . . . . . Strumigenys xenognatha


 * Mandible with 3 preapical teeth or denticles, sometimes also with an additional tiny preapical denticle located very close to the apex . . . . . 10

10
return to couplet #9
 * Proximal (basal most) of the three preapical mandibular teeth or denticles distinctly longer and broader-based than the median tooth or denticle. (Colombia) . . . . . Strumigenys gemella


 * Median of the three preapical mandibular teeth or denticles distinctly longer and broader-based than the proximal (basal most) tooth or denticle . . . . . 11