Strumigenys ohioensis group

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Strumigenys ohioensis group Bolton (2000)

Species

Nearctic

Worker Diagnosis

Mandibles in full-face view and at full closure triangular, either serially dentate with masticatory margins that engage through all their visible length or with a small edentate gap present between basal tooth and anterior clypeal margin. In ventral view outer margin of mandible without an inflected prebasal angle. MI 16-25.

Dentition. Principal tooth row with 5 sharp triangular teeth. Tooth I (basal) and 2 subequal in size or 1 shorter than 2. Tooth 3 distinctly the longest tooth on the margin and tooth 4 reduced, smaller than 3 or 5. Tooth 5 usually only slightly shorter than 3; 5 equal in length to 2 or longer. Tooth 5 followed by two small teeth, 4 minute denticles and a small apical tooth, giving a total dental count of 12.

Basal lamella of mandible triangular, broad-based and a t least a s long a s the longest tooth, not visible to mostly visible in full-face view with the mandibles fully closed. Basal lamella not separated from basal tooth or with a moderate diastema present.

Labrum terminates in a pair of narrow digitate to conical lobes.

Clypeus with anterior margin evenly shallowly convex in full-face view. Lateral clypeal margins weakly convergent anteriorly, in full-face view approximately continuing the line of the outer margins of the fully closed mandibles. Clypeus without peripheral groove.

Clypeal lateral margins with a fringe of filiform to narrowly spatulate projecting hairs that are not uniformly curved anteriorly. Anterior margin with similar but smaller hairs.

Clypeal dorsum with filiform or fine narrowly spatulate hairs that are arched or elevated, not closely appressed.

Preocular carina broad and conspicuous in full-face view.

Ventrolateral margin of head between eye and mandible bluntly marginate. Postbuccal impression small and shallow to vestigial.

Cuticle of side of head within scrobe reticulate or reticulate-punctate.

Scape short to moderate, SI 67 - 87, weakly dorsoventrally flattened but with a well defined leading edge.

Leading edge of scape with fine filiform or extremely narrowly spatulate projecting hairs, at least one or two of which, close to the subbasal bend, are curved toward the base of the scape.

Propodeum with triangular teeth subtended by a lamella on each side that is sometimes very narrow.

Spongiform appendages well developed on petiole and postpetiole; ventral spongiform curtain of petiole well developed. Base of first gastral sternite in profile with a narrow band or thin pad of weak or diffuse spongiform tissue.

Pilosity. Pronotal humeral hair present, filiform or flagellate. Dorsum of head behind clypeus with curved ground-pilosity that is filiform or extremely narrowly spatulate.

Apicoscrobal hair present. First gastral tergite with long flexuous to flagellate hairs.

Basitarsus of hind leg with at least one long flagellate hair on its dorsal (outer) surface.

Sculpture. Dorsum of head behind clypeus reticulate-punctate. Pleurae, side of propodeum and disc of postpetiole smooth.

Notes

The two species included in this weakly defined group, ohioensis and reliquia, are probably not really closely related. Both show features that imply direct, but possibly independent, derivation from the rostrata group (dentition, scape pilosity) but together they differ from the members of that group by their much finer pilosity.

References

  • Bolton, B. 2000. The ant tribe Dacetini. Memoirs of the American Entomological Institute. 65:1-1028.