Strumigenys biroi group

Strumigenys biroi group Bolton (2000)

Species

Malesian-Oriental-East Palaeartic

Strumigenys undras also occurs in the Austral region.

Worker Diagnosis

Apical fork of mandible of 2 teeth; one small intercalary tooth present or a small tooth plus a minute denticle. A single preapical tooth present close to apex, preapical tooth shorter than maximum width of mandible. Mandibles short (MI 28-32), very broad at base, conspicuously and rapidly tapered from base to apex, not linear or curvilinear. In ventral view outer margin of mandible with an inflected prebasal angle.

Anterior clypeal margin transverse.

Scape stout, subcylindrical to slightly dorsoventrally flattened, short, SI 60-70.

Apical antennomere not constricted basally.

Ventrolateral margin of head without a preocular notch or impression. With head in profile the dorsal and ventral outlines without impressions except for the postbuccal groove.

Propodeal declivity with lamella absent, broadly lamelliform, or massively spongiform; when present its posterior (free) margin undulate or convex.

Spongiform appendages of waist segments all present.

Pilosity. Apicoscrobal hair absent. Cephalic dorsum without standing hairs or at most with a single pair that straddles the midline close to the occipital margin. Pronotal humeral hair absent, or present and flagellate; pronotal dorsum otherwise without standing hairs. Mesonotum without standing hairs or with 1 erect pair. First gastral tergite hairless or hairs very sparse.

Sculpture. Variable within group but gaster unsculptured except for basigastral costulae.

Notes

There are three New Guinea-based species in this group, one of which (Strumigenys undras) also occurs in Australia, and a fourth species that is apparently restricted to the Fiji Islands. All have mandibles that are modified in the same way as the lyroessa-group, though not as extensively. I suspect that the similar appearance has been acquired convergently by some members of the group.

References

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