Oligomyrmex borealis

Japanese Name

Oo-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 1.5 mm in workers. One of the larger Japanese Oligomyrmex species. Body color yellowish brown. In soldiers: head 1.1 times as long as wide, sides slightly converging anteriorly, posterior margin concave in full face view, vertex with a pair of tubercles; mandibles each with 6 teeth; antennae 9-segmented; eyes small, each with more than 5 facets, situated at midlength of head capsule in side view; pronotal and mesonotal dorsa distinctly produced; mesonotum obscurely divided into mesoscutum and scutellum; mesopleuron separated into two parts by an oblique furrow; metanotum distinct; posterodorsal corners of propodeum each with a triangular tooth; posterolateral margins of propodeum carinate; subpetiolar process small, forming a blunt triangle; head punctate, with many longitudinal rugae; pro- and mesonota mostly smooth; mesopleura, metanotum and propodeum punctate, petiole and lateral surfaces of postpetiole covered with small punctures. In workers: head slightly longer than wide in full face view; antennae 9-segmented; mandibles each with 5 teeth; eyes each with a single facet, situated at midlength of head capsule; posterolateral margins of propodeum with a thin lamellate flange running from posterodorsal corner; propodeal spines present, triangular, their tips turned upwards; head and pronotum mostly smooth; mesonotum, propodeum, petiole and postpetiole covered with small punctures.

This is a very rare species with only three collection records from Honshu.

Honshu (Aomori, Akita, Yamanashi).