Aphaenogaster irrigua

This species prefers moist situations; it nests in the soil in woodlands, near banks of streams and dry river beds. Foraging workers do not turn their gasters downwards.

Identification
Total length of workers around 4 - 6 mm. Head brown to light brown, mesosoma light brown, gaster dark brown to brown, legs light brown. Scapes, mesosoma and legs relatively rather long compared to other Japanese Aphaenogaster species. Anterior portion of clypeus with transverse striae. Basal margin of mandibles often weakly serrate. Mesonotum only weakly raised, predominantly covered with punctures. Similar to Aphaenogaster osimenseis, but separable by the presence of shallow, small punctures on the occiput and pronotal dorsum, and the dull surfaces of the propodeum and lateral parts of mesopleura, which are covered with striae and punctures. (Japanese Ant Image Database)

Distribution based on Regional Taxon Lists
Palaearctic Region: Japan.

Biology
Chromosome number 2n=32.

Nomenclature

 *  irrigua. Aphaenogaster irrigua Watanabe & Yamane, 1999: 734, fig. 18 (w.) JAPAN.