Temnothorax santra

A rare species. The known specimens were collected in leaf litter samples using a Berlese funnel (Terayama and Onoyama 1999; Japanese Ant Image Database).

Identification
Terayama and Onoyama (1999) - Total length of workers around 2.5 mm. Body color yellowish brown; head darker than mesosoma and gaster. Scapes slightly exceeding posterior margin of head in full-face view. Dorsal outline of mesonotum weakly convex. Metanotal groove very weakly incised dorsally. Propodeal spines relatively ·short: each about twice as long as its basal width when viewed laterally; its dorsal margin forming an angle at its midlength. Petiolar peduncle relatively short, in profile not distinctly narrowed anteriorly; node reverse U-shaped.

T. santra resembles Temnothorax haira, but distinguished by the mesonotal and propodeal sides with predominantly longitudinal rugulae and the more upwardly directing propodeal spines.

Distribution
Ogasawara Is. (Chichi-jima I., Ani-jima I.).

Distribution based on Regional Taxon Lists
Palaearctic Region: Japan.

Nomenclature

 *  santra. Leptothorax santra Terayama & Onoyama, 1999: 92, figs. 27, 28 (w.) JAPAN. Combination in Temnothorax: Bolton, 2003: 271.

Worker
Holotype. HL 0.61 mm; HW 0.50 mm; CI 82; SL 0.48 mm; SI 96; WL 0.73 mm; PW 0.35 mm; PtW 0.16 mm; PtH 0.20 mm; TL 2.5 mm.

Head 1.2 times as long as wide, with weakly convex posterior margin in full-face view; sides of head behind eyes slightly converging posteriorly; posterodorsal corners rounded. Mandibles finely and longitudinally rugulose. Anterior margin of median clypeal lobe gently convex. Antennae with 12 segments; scapes slightly exceeding posterior margin of head in full-face view. Eyes 0.14 mm in maximum diameter, with about 12 facets in the longest row.

Dorsal outline of mesonotum in profile weakly convex. Metanotal groove very shallowly incised dorsally. Propodeal dorsum straight in profile. Propodeal spines in lateral view acute and relatively short, each about twice as long as its basal width, its dorsal margin forming a distinct angle of 150 degrees at its midlength, ventral margin straight at its posterior 2/ 3.

Petiolar peduncle relatively short, in profile not distinctly narrowed anteriorly; node reverse U-shaped, anterior and posterior margins gradually converging to the dorsum. Subpetiolar process vestigial. Postpetiole higher than long, with almost straight dorsal margin in profile; node in dorsal view 1.8 times as wide as long, with parallel sides.

Clypeus longitudinally rugulose, with a long, conspicuous median carina. Head dorsum longitudinally rugulose with sparse cross-meshes, the spaces between densely punctulate. Pronotal dorsum rugose, pronotal sides longitudinally rugulose; the rest of mesosoma mostly longitudinally rugulose with punctulae except for propodeal declivity which is densely punctulate. Petiole and postpetiole densely punctulate. Gaster smooth.

Head dorsum with relatively abundant erect hairs. Mesosomal dorsum with 8-9 pairs, petiole with 2 pairs, and postpetiole with 5-6 pairs of stout, erect hairs. Propodeal spines each with a short erect hair slightly behind the angled corner at the midlength of dorsal margin. Gaster with moderately abundant erect hairs.

Body and appendages yellowish brown; head (excluding mandibles) and antenna! clubs brown.

Type Material
Holotype. Worker, Hatsune-yama, Chichi-jima I., Ogasawara Is, Tokyo Pref., 9.VII.1996, T. K. leg. Paratype. 1 worker, Kita-futago-yama, Ani-jima I., Ogasawara Is, Tokyo, 1.VIII.1996, T. K. leg.

References based on Global Ant Biodiversity Informatics

 * Terayama M., S. Kubota, and K. Eguchi. 2014. Encyclopedia of Japanese ants. Asakura Shoten: Tokyo, 278 pp.
 * Terayama M., and S. Kubota. 2002. Ants of Tokyo, Japan. ARI 26: 1-32.
 * Terayama M.; Onoyama, K. 1999. The ant genus Leptothorax Mayr (Hymenoptera: Formicidae) in Japan. Memoirs of the Myrmecological Society of Japan 1:71-97.