Strumigenys omopyx group

Strumigenys omopyx group Bolton (2000)

Species

Malesian-Oriental-East Palaeartic

Worker Diagnosis

Apical fork of mandible of 2 spiniform teeth; without intercalary dentition or with a denticle that arises from the dorsal surface of the apicoventral tooth. A single very small preapical tooth present, hardly more than a denticle. In full-face view inner margin of mandible straight to curved from base to about apical quarter but, in vicinity of preapical tooth, the margin abruptly becoming concave with respect to its previous line; preapical tooth or denticle located at proximal commencement of concavity or upon the concave section itself. Mandibles more or less straight, MI 46-50.

Anterior clypeal margin shallowly to deeply concave.

Scape slender and subcylindrical, very slightly dorsoventrally flattened; short to moderately long, SI 68-83.

Apical antennomere spindle-shaped, strongly constricted basally and narrowly articulated with the preapical antennomere.

Ventrolateral margin of head with a constriction or a broad shallow concavity in front of eye. With head in profile the dorsal and ventral outlines without impressions except for the postbuccal groove.

Propodeal declivity with a narrow and inconspicuous lamella, or merely with a carina; posterior (free) margin of lamella is concave and parallels the margin of the declivity.

Spongiform appendages of waist segments all present, small.

Pilosity. Flagellate hairs and long fine simple hairs entirely absent. Apicoscrobal hair short and stiff, directed more dorsally than laterally. Short stiff standing hairs present on cephalic dorsum, mesonotum (1 pair), waist segments and first gastral tergite, longest on the last of these. Pronotal humeral hair absent or present, when present short and blunt. Dorsal (outer) surfaces of middle and hind basitarsi without long erect hairs. Ground-pilosity on head sparse and short, simple to narrowly spatulate.

Sculpture. Head, alitrunk and petiole finely densely reticulate-punctate except for katepisternum which is mostly or entirely smooth. Disc of postpetiole usually finely reticulate-punctate but sculpture may be effaced; disc never entirely smooth and shining. Gaster unsculptured except for basigastral costulae.

Notes

In most groups of Strumigenys the mandible, in full-face view, possesses an inner margin that forms a continuous line from base to apicodorsal tooth. The line of the margin may be interrupted by one or more preapical teeth or denticles but the line established proximal of the preapical tooth is continued distal to it without a marked change in shape or direction. On the other hand, in the omopyx-group and a few others (koningsbergeri group, loriae group) the line of the inner margin changes abruptly in the vicinity of the preapical tooth or denticle, becoming suddenly concave with respect to the line established by the proximal majority of the length of the margin. Members of the loriae-group are easily distinguished from Strumigenys omopyx and its relatives as the former have very irregularly shaped head capsules (see diagnosis of group). Species of the koningsbergeri-group do not have the spindle-shaped, basally attenuated and very narrowly articulated apical antennomere that characterises the members of the omopyx-group.

References

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