Strumigenys circothrix

Identification
Bolton (2000) - Characters separating this species from its only close relative, Strumigenys hiroshimensis, are given under the latter name.

Strumigenys circothrix group

Distribution based on Regional Taxon Lists
Palaearctic Region: Japan.

Nomenclature

 *  circothrix. Smithistruma circothrix Ogata & Onoyama, 1998: 280, figs. 3, 4 (w.) JAPAN. Combination in Pyramica: Bolton, 1999: 1673; in Strumigenys: Baroni Urbani & De Andrade, 2007: 117. See also: Bolton, 2000: 410.

Worker
Bolton (2000) - TL 1.7-1.9, HL 0.45-0.48, HW 0.37-0.39, CI 80-85, ML 0.08-0.12, MI 20-25, SL 0.18-0.23, SI 50-59, PW 0.20-0.24, AL 0.45-0.48 (4 measured).

Basal tooth of mandible the longest; basal and third teeth narrowly conical and acute, contrasting strongly with the lower, broadly rounded second tooth; these visible in full-face view when mandibles fully closed. With head in full-face view all hairs on dorsum suborbicular; those on clypeus small, those on frons and vertex larger. Hairs fringing clypeus and dorsolateral margins of head broadly spoon-shaped to suborbicular, curved anteriorly and closely applied to the surface; without specialised freely projecting elongate hairs of any form anywhere on the sides or dorsum of the head. Small flat scale-like hairs present on mandibles and dorsa of scapes. Hairs on leading edge of scape that curve toward apex of scape largest basally, proximal of the broad subbasal curve of the margin. Dorsum of head uniformly finely reticulate-punctate. Pronotal humeral hair very short, stout and clavate. Promesonotal dorsum with scattered small appressed flattened hairs, the mesonotum with a single pair of short straight clavate hairs that are about equal in length to those at the pronotal humeri. Apically thickened to clavate standing hairs present on petiole and postpetiole, numerous on gaster. Dorsal (outer) surfaces of middle and hind tibiae with small broad hairs that are curved apically and closely applied to the surface. Pronotal dorsum with feeble faint longitudinal costulae, the surface between them faintly superficially punctulate. Mesonotum and propodeal dorsum more conspicuously reticulate-punctate. Side of alitrunk smooth and shining except near the dorsum. Petiole in dorsal view broader than long, the lateral spongiform lobes and posterior collar distinct. In profile the lateral spongiform lobe of the petiole confined to the posterolateral angle. Disc of postpetiole glassy smooth, much broader than long, with evenly convex lateral margins. Lateral and ventral spongiform lobes of postpetiole in profile both at least equal in area to the exposed disc, the ventral lobe larger than the lateral. Basigastral costulae short but strongly developed, arising across the entire width of the tergite.

Type Material
Bolton (2000) - Holotype and paratype workers, JAPAN: Ryukyus, Ishigaki I., Mt Banna, 20.vi.1991 (K. Morimoto); paratype workers and queen, Kumejima I., Ryukyus, 19.viii.1983 (H. Takamine); Nago, Okinawa I., Ryukyus, 27.vi.1974, (T. Abe) (KU, ) [examined].