Strumigenys silvestrii group

Strumigenys silvestrii group Bolton (2000)

Species

Neotropical-Nearctic

• Strumigenys ascita
• Strumigenys acarai
• Strumigenys calamita
• Strumigenys carinithorax
• Strumigenys dyseides
• Strumigenys epelys
• Strumigenys gytha
• Strumigenys insolita
• Strumigenys nastata
• Strumigenys obliqua
• Strumigenys perdita
• Strumigenys perparva
• Strumigenys quadrua
• Strumigenys ruta
• Strumigenys schmalzi
• Strumigenys silvestrii
• Strumigenys skia
• Strumigenys timicala
• Strumigenys waiwai
• Strumigenys xochipili

Worker Diagnosis

Apical fork of mandible usually without intercalary denticles (see below). Mandible usually with one spiniform preapical tooth, located in the distal third, and with a minute denticle, that may be difficult to see, just proximal of midlength (one species with 2 spiniform preapical teeth, one with distal spiniform tooth only, one merely with 2 minute dentic1es). MI 45 - 68.

Leading edge of scape with two or more hairs that are curved or inclined toward the base of the scape. Scape subcylindrical to somewhat flattened, subbasal bend usually well developed (feeble in one species); short to moderate, SI 62 - 91.

Eyes usually minute, generally with only 1 - 3 ommatidia in total though in some 6 or more may be present.

Ventrolateral margin of head in front of eye sharply defined, not indented or concave. Postbuccal groove shallowly impressed.

Preocular carina in profile short, terminates before level of the eye. Upper scrobe margin sharply defined behind level of eye.

Propodeum in profile usually with a triangular tooth that is subtended by a lamella or carina that extends down the declivity; base of declivity unarmed or angulate.

Petiole in dorsal view at least as broad as long, generally much broader than long; spongiform tissue absent from ventral surface of petiole except in 3 Central American species.

Pilosity. Pronotal humeral hair present, may be simple, remiform or flagellate.

Sculpture. Head and alitrunk usually reticulate-punctate but pleurae and side of propodeum usually mostly to entirely smooth, only rarely entirely sculptured.

Minute species, HL 0.36 - 0.52, HW 0.28 - 0.44.

Notes

The 18 species of this group are among the smallest in the Neotropical region, and in many cases the size alone will define a member of the group. Most are known from relatively little material and it is most likely that many more species of the silvestrii-group await discovery.

As noted above the apical fork of the mandible usually lacks any trace of intercalary teeth or denticles in this group. However, in most populations of Strumigenys silvestrii there is a minute tumulus between the apicodorsal and apicoventral teeth, often with a small hair arising from it. In Strumigenys xochipili there is a single, acute intercalary tooth that arises from the dorsal surface of the apicoventral tooth, at its base.

References

• Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028.
• Brown, W. L., Jr. 1959f. The neotropical species of the ant genus Strumigenys Fr. Smith: group of silvestrii Emery. Studia Entomologica. 2:25-30.