Oligomyrmex oni

Japanese Name

Oni-kotsuno-ari

Terayama, M. (1996) Taxonomic studies of the Japanese Formicidae, part 2. Seven genera of Ponerinae, Cerapachyinae and Myrmicinae. Nature and Human Activities, 1, 9-32.

Total length around 3.5 mm in soldiers, around 1 mm in workers. One of the larger Japanese Oligomyrmex species. Body color reddish brown, except the head which is blackish brown in soldiers, yellowish brown in workers. In soldiers: head 1.1 times as long as wide, posterior margin slightly concave at midline in full face view; a single median ocellus present in many individuals; tubercles on vertex variously present, ranging to obscure or absent; mandibles each with 6 teeth; eyes each with more than 10 facets, situated laterally on anterior portion of head capsule, and bearing hairs which are longer than the diameter of a single facet; antennae 9-segmented; mesonotal dorsum produced, divided into mesoscutum and scutellum; mesopleura divided by an oblique furrow. Metanotum distinct; propodeal teeth triangular, with rounded apices; posterolateral margins of propodeum not carinate; subpetiolar process forming an acute tooth; head with numerous longitudinal rugae and small punctures; dorsa of pronotum and mesonotum mostly smooth and shining, propodeum, petiole and postpetiole with small punctures. In workers: head almost square in frontal view; its posterior margin shallowly convex at midline; anterior margin of clypeus strongly convex at the midline; eyes each with 2 or 3 facets; propodeal spines slender and acute, each as long as or longer than its basal width; posterolateral margins of propodeum each with a thin lamellate flange, its upper end not reaching the propodeal spine; petiole relatively low; subpetiolar process spinose, with an acute anteroventral corner; head and pronotum largely smooth and shining; mesonotum, propodeum, petiole and postpetiole with small punctures.

This species is found in evergreen broad-leaved forests, nesting in soil or rotting wood.

Nansei Is (Okinawa I., Tokashiki I.).