Strumigenys semicompta group

Strumigenys semicompta group Bolton (2000)

Species

Austral

• Strumigenys flagellata
• Strumigenys semicompta

Malesian-Oriental-East Palaeartic

• Strumigenys carnassa
• Strumigenys pydrax
• Strumigenys semicompta

Worker Diagnosis

The group is diagnosed, with slight differences, for two different regions:

Austral

Mandibles in full-face view and at full closure sub triangular to triangular, serially dentate; masticatory margins engage throughout their length or at most with a minute diastema between basal tooth and basal lamella. In ventral view outer margin of mandible with a weak to distinct inflected prebasal angle. MI 12-20.

Dentition. Mandible with 5 stout recurved conical teeth only, without denticles; total dental count 5.

Basal lamella a high truncated triangle or rectangle, higher than long, its anterior margin visible in front of the anterior clypeal margin, even when mandibles fully closed.

Labrum broadly bilobate apically, the lobes flat and truncated, separated by a V-shaped anteromedian impression.

Clypeus with anterior margin transverse to shallowly convex; outer margins of mandibles intersect anterior clypeal margin at or just mesad of the clypeal anterolateral angles.

Clypeal dorsum with minute appressed hairs that may be simple or narrowly spatulate.

Preocular carina narrow but at least partially visible in full-face view; at minimum visible only through minute notch between clypeus and frontal lobe.

Ventrolateral margin of head marginate in front of eye. Postbuccal impression deep.

Cuticle of side of head within scrobe partially to entirely sculptured.

Scape subcylindrical to slightly dorsoventrally flattened, the leading edge shallowly convex.

Leading edge of scape with minute hairs that are directed toward the scape apex; appressed or elevated and simple to spatulate in shape.

Spongiform appendages of petiole and postpetiole large, well developed ventrally and laterally; petiole node without a posterior spongiform collar dorsally. Base of first gastral sternite in profile with a distinct pad or arcuate strip of dense spongiform tissue.

Pilosity. Pronotal humeral hair present, simple to flagellate.

Sculpture. Dorsum of head behind clypeus superficially punctulate to punctate-rugulose. Pleurae, side of propodeum and disc of postpetiole smooth and shining.

Malesian-Oriental-East Palaeartic

Mandibles in full-face view and at full closure subtriangular to triangular, serially dentate, the masticatory margins engage throughout their length or at most with a minute diastema between basal tooth and basal lamella. In ventral view outer margin of mandible with a weak to distinct inflected prebasal angle. MI 12-20.

Dentition. Mandible with 5 stout recurved conical teeth; total dental count is 5.

Basal lamella a high truncated triangle or rectangle, higher than long, its anterior margin visible in. front of the anterior clypeal margin even when mandibles fully closed.

Labrum broadly bilobate, the lobes flat and truncated apically, separated by a V-shaped anteromedian impression.

Clypeus with anterior margin transverse to shallowly convex; outer margins of mandibles intersect anterior clypeal margin at or just mesad of the clypeal anterolateral angles.

Clypeal dorsum with minute appressed hairs that may be simple or narrowly spatulate.

Preocular carina narrow but at least partially visible in full-face view; at minimum visible only through minute notch between clypeus and frontal lobe.

Ventrolateral margin of head marginate in front of eye. Postbuccal impression deep.

Cuticle of side of head within scrobe partially to entirely sculptured.

Scape very short to moderate, SI 44-75, subcylindrical to slightly dorsoventrally flattened, the leading edge shallowly convex.

Leading edge of scape with minute apically directed hairs that are appressed or elevated and simple to spatulate in shape.

Spongiform appendages of petiole and postpetiole large, well developed ventrally and laterally; petiole node without a posterior spongiform collar dorsally. Base of first gastral sternite in profile with a distinct pad or arcuate strip of hair-like to dense spongiform tissue.

Pilosity. Pronotal humeral hair present or absent.

Sculpture. Dorsum of head behind clypeus smooth, superficially punctulate or punctate-rugulose.

Pleurae, side of propodeum and disc of postpetiole smooth and shining.

Notes

Austral

This group currently contains four species; two from New Guinea (carnassa, pydrax), one from Queensland (flagellata), and one from both Australia and New Guinea as well as other islands close to New Guinea (semicompta). The extremely low dental count of 5, combined with the form of the basal lamella and labrum, is immediately diagnostic of the group.

Malesian-Oriental-East Palaeartic

Four species of this group are known, two from the current faunal region (Strumigenys carnassa, Strumigenys pydrax), one only from Queensland, Australia, which may yet be found in New Guinea (Strumigenys flagellata), and one that is already known from both regions (Strumigenys semicompta). The extremely low dental count of 5, combined with the form of the basal lamella and labrum, is immediately diagnostic of the group. For further comments on the group see under carnassa.

References

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