Pheidole susanowo

The holotype colony was found in the soil of a sugarcane field. Another colony was collected at a wood margin near a sugarcane field. Otherwise a very rare species.

Identification
Onoyama and Terayama (1999) - Pheidole susanowo resembles Pheidole fervens and Pheidole oceanica, but is distinguished by the much smaller size and relatively shorter scape in the soldier and worker, or by the more angulate corner of head in the soldier, or the reticulate-punctate pronotal sides in the worker. This species is distinguished from other Japanese Pheidole species by the sculpturation on the whole of mesosoma, especially by the wholly reticulate-punctate pronotal sides, and dark coloration of body.

Distribution based on Regional Taxon Lists
Palaearctic Region: Japan.

Nomenclature

 *  susanowo. Pheidole susanowo Onoyama & Terayama, 1999: 66, figs. 1-5 (s.w.) JAPAN.

Worker
Major/Soldier HL 1.15, 1.14 mm; HW 1.06, 1.07 mm; CI 92, 94; HD 0.73, 0.70 mm; SL 0.52, 0.48 mm; SI 49, 45; EL 0.15, 0.14 mm; PW 0.56, 0.55 mm; WL 0.88, 0.86 mm; PSL 0.08, 0.06 mm; PtW 0.17, 0.16 mm; PpW 0.29, 0.27 mm. (2 measured, the former figures for holotype and the latter for a paratype.)

Head longer than wide with convex sides, posterior margin concave in the middle; median sulcus distinct, anteriorly reaching beyond the midlength of head in full-face view, but not reaching to frontal triangle. Eyes oval and small, with about 30 facets. Clypeus with a median carina; anterior margin with a distinct median notch. Mandibles each practically with 4 teeth, apical and subapical acute and large, basal and offset basal low. Scapes short, reaching the midlength of head; segment II as long as segments III to VI together, segments III and VI as long as wide, IV and V wider than long, VI as long as wide, VII to XI longer than wide, apical segment as long as segments X and XI together. Frontal carinae diverging posteriorly, reaching the midlength of head. Gular dentition (the arrangement of gular teeth in the soldier) developed as in Figure, paired mesial teeth a little closer to midgular tubercle than to lateral teeth.

Pronotum prominently raised in profile; humeri rounded and much protruding laterally m dorsal view, each forming a tubercle. Mesonotum a little convex in profile. Metanotal groove shallowly incised dorsally. Propodeal dorsum concave in the middle, but in profile nearly strmght. Propodeal spines acute, directing upwards and slightly backwards and outwards. Petiole with concave anterior slope and convex ventral margin in profile and with a very shallowly concave crest and parallel sides in posterior view. Petiole about 1.7 times as long as postpetiole. Postpetiole higher than long, and lower than petiole in profile; hexagonal in dorsal view, a little more than twice as wide as long, sides much protruding laterally. Mandibles smooth and shining. Head dorsum, mesosoma, petiole and pospetiole reticulate-punctate and opaque except for the clypeus and the area between frontal carinae, and the propodeal declivity. Basal 1/3 of gastral tergite I somewhat weakly reticulate-punctate and opaque, the remainder of gaster smooth and shining.

Body abundantly covered with long, erect or suberect, pale yellow hairs. Appendages with shorter, mostly suberect to decumbent hairs.

Mandibles dark brown. Head to postpetiole blackish brown. Basal 1/3 of gastral tergite I medium brown, the remainder of gaster dark brown. Antennae and legs slightly light brown.

Minor HL 0.49-0.57 mm; HW 0.43-0.52 mm; CI 88-91; HD 0.33-0.39 mm; SL 0,42-0.49 mm; SI 91-100; FLW 0.19-0.21 mm; EL 0.l0-0.11 mm; PW 0.29-0.36 mm; WL 0.56-0.67 mm; PSL 0.04-0.05 mm; PtW 0.08-0.12 mm; PpW 0.12-0.15 mm. (5 measured.)

Posterior margin of head a little concave in the middle. Anterior c1ypeal margin straight in the middle. Occipital border concave in the middle (no sulcus). Scapes, when laid back, extending about their thickness beyond the head. Antennal segment II twice as long as wide, III as long as wide, IV to VIII each wider than long, IX as long as wide, X twice as long as wide, XI 1.5 times as long as wide, apical 2.5 times as long as wide. Eyes of medium size, with about 30 facets. Pronotum and mesonotum nearly forming a convexity. Propodeal dorsum nearly flat. Postpetiole hexagonal in dorsal view, about twice as wide as long, sides protruding laterally. Gastral tergite I smooth and shining. Other morphology, sculpturation, and coloration are as in the soldier.

Type Material
Holotype: Soldier, northwest of Arakawa, Ishigaki 1., Okinawa Pref., 10 m above sea level, l.VII.l974, K. Onoyama leg. Paratypes. 1 worker, Chichi-jima 1., Ogasawara Is., Tokyo .Pref., 30.VII.1972, M. Tanaka leg.; 2 workers, Uebaru, Naha City, Okmawa PreL, 21.VIII.l996, H. Takamine leg.; 2 soldiers, 7 workers, same data as in holotype 1 soldier and 5 workers, northwest of Arakawa (near the type locality), Ishigaki 1., Okinawa Pref., 1.V!I.l974, K. Onoyama leg. 2 soldiers, 3 workers, the experimental field of the Tropical Agriculture Research Center, Maesato, Ishigaki 1., Okinawa Pref., 24.VII.1992, K. Yasuda leg. The holotype and paratypes will be deposited in.

Determination Clarifications
Pheidole sp. D: Onoyama, 1976; Pheidole sp. 8: Ogata and Yamaane, 1992

References based on Global Ant Biodiversity Informatics

 * Eguchi K., S. Yamane, and S.Y. Zho. 2007. Taxonomic revision of the Pheidole rinae Emery complex. Sociobiology 50 (1): 275-284.
 * Nakamura M., S. Uchikoba, and Y. Harada. 2016. Ants of housing lots on the Ryukyu Islands, southern Japan. Nature of Kagoshima 42: 465–468.
 * Onoyama K., and M. Terayama. 1999. A new species of the ant genus Pheidole Westwood from Japan (Hymenoptera: Formicidae). Memoirs of the Myrmecological Society of Japan 1: 65-69.
 * 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.
 * Yamane S., S. Ikudome, and M. Terayama. 1999. Identification guide to the Aculeata of the Nansei Islands, Japan. Sapporo: Hokkaido University Press, xii + 831 pp. pp, 138-317.
 * Yamane S.; Ikudome, S.; Terayama, M. 1999. Identification guide to the Aculeata of the Nansei Islands, Japan. Sapporo: Hokkaido University Press, xii + 831 pp. pp138-317.