Aenictus lifuiae

In Japan this species is found in evergreen broad-leaved forests and their margins where it nests in soil and is rare (Japanese Ant Image Database). Terayama (1984) reported that the material from Meishan Cun was taken “at hard clay soil of the road cutting about 50 cm above ground level”. When another person saw it at 5 p.m., the colony was prepared for the nuptial flight. One male was in the nest entrance, and about 40 workers were seen coming out of the nest, gathering around the entrance in a circle (Jaitrong & Yamane, 2013).

Identification
A member of the ceylonicus group. Jaitrong and Yamane (2013) - Smaller specimens of A. lifuiae collected from Iriomote-jima and Okinawa-jima, southern Japan, have a mandible that is almost linear, an anterior clypeal margin that is straight or weakly concave, and a gap between between the mandibles and anterior clypeal margin. These characteristics are used to separate the A. ceylonicus group from the other groups of the genus Aenictus.

Aenictus lifuiae, though variable in size and associated morphological characters, is easily distinguished from the other members of the group as follows: masticatory margin of mandible with large acute apical tooth followed by a series of 6–7 denticles of two sizes, the larger alternating with 1–2 smaller (almost same size as in the other members of the group); a gap between anterior clypeal margin and mandibles rather small or indistinct, maximum width shorter than 1 time as wide as maximum width of mandible (large and distinct in the others).

Three specimens collected from Okinawa-jima, Japan are slightly larger than the type series from Taiwan (HW 0.48–0.53 mm in the type series; 0.55–0.58 mm in Okinawan specimens).

Distribution based on Regional Taxon Lists
Oriental Region: Taiwan. Palaearctic Region: China, Japan.

Castes
Unusual for the genus in that workers and males are known for this species.

Nomenclature

 * . Aenictus lifuiae Terayama, 1984: 13, figs. 1-13 (w.m.) TAIWAN.
 * Status as species: Morisita, et al. 1989: 34; Xu, 1994a: 120; Bolton, 1995b: 60; Imai, et al. 2003: 209; Lin & Wu, 2003: 60; Wang, W. 2006: 637 (in key); Terayama, 2009: 124; Jaitrong & Yamane, 2013: 196 (redescription); Staab, 2015: 141 (in key).

Worker
Jaitrong and Yamane (2013) - (holotype and paratypes, n = 10). TL 2.55–2.80 mm; HL 0.53–0.58 mm; HW 0.48–0.53 mm; SL 0.39–0.45 mm; ML 0.75–0.88 mm; PL 0.18–0.23 mm CI 90–91; SI 82–86.

Non-type workers (larger): TL 2.80–2.85 mm; HL 0.55–0.58 mm; HW 0.50–0.53 mm; SL 0.40–0.41 mm; ML 0.83–0.88 mm; PL 0.20–0.23 mm CI 91–95; SI 76–80.

Non-type workers (smaller): TL 2.10–2.20 mm; HL 0.48–0.50 mm; HW 0.40–0.43 mm; SL 0.23–0.25 mm; ML 0.63–0.68 mm; PL 0.15–0.18 mm CI 84–85; SI 56–59.

(holotype and paratypes). Head in full-face view subrectangular, distinctly longer than broad, with sides slightly convex and posterior margin almost straight. Antennal scape extending beyond midlength of head, but not reaching 2/3 of head length; antennal segment II almost as long as III and each longer than broad; IV-VIII each slightly broader than long; terminal segment about 2 times as long as broad. Frontal carina short, slightly extending beyond the level of posterior margin of torulus. Masticatory margin of mandible with a large apical tooth, followed by 6 teeth of two sizes, a larger alternating with a smaller; basal margin lacking denticles. In smaller workers maximum width of gap between anterior clypeal margin and mandibles about 0.9–1.0 times as broad as maximum width of mandible (larger workers almost lacking the gap). Promesonotum in profile strongly convex dorsally and sloping gradually to metanotal groove; metanotal groove rather distinct but shallow; mesopleuron clearly demarcated from metapleuron by a shallow groove; metapleural gland bulla relatively large and transparent, its maximum diameter about 3.0–3.5 times as long as distance between propodeal spiracle and metapleural gland bulla. Propodeum in profile with weakly convex to almost straight dorsal outline; propodeal junction angulated; declivity of propodeum narrowly and shallowly concave, encircled with a distinct rim. Petiole excluding subpetiolar process almost as long as high, with its dorsal outline convex; subpetiolar process weakly developed, with its ventral outline convex. Postpetiole clearly shorter than petiole, its dorsal outline convex.

Head and gaster entirely smooth and shiny. Mandible very finely striate. Antennal scape entirely superficially microreticulate, but shiny. Promesonotum entirely smooth and shiny except for reticulate anteriormost portion; mesopleuron, metapleuron, lateral face of propodeum reticulate; dorsal face of propodeum punctate, somewhat shiny; petiole with reticulate lateral face and smooth and shiny dorsal face; postpetiole same as petiole. Legs smooth and shiny.

Head and mesosoma dorsally with relatively dense standing hairs; longest pronotal hair 0.13–0.15 mm long. Head, petiole, postpetiole, gaster, and legs yellowish brown; mesosoma reddish brown.

Type Material
Jaitrong and Yamane (2013) - Holotype (NAIST), 152 paratype workers (NAIST, TARI) and 1 paratype male (NAIST) from Taiwan, Kaoshiung Hsien, Taoyuan Xiang, Meishan Cun (ca. 800 m alt.). Holotype and nine paratype workers were examined.

References based on Global Ant Biodiversity Informatics

 * Guénard B., and R. R. Dunn. 2012. A checklist of the ants of China. Zootaxa 3558: 1-77.
 * Jaitrong W., and S. Yamane. 2013. The Aenictus ceylonicus species group (Hymenoptera, Formicidae, Aenictinae) from Southeast Asia. Journal of Hymenoptera Research 31: 165-233.
 * Li Z.h. 2006. List of Chinese Insects. Volume 4. Sun Yat-sen University Press
 * Terayama M. 1992. Structure of ant communities in East Asia. A. Regional differences and species richness. Bulletin of the Bio-geographical Society of Japan 47: 1-31.
 * Terayama M. 2009. A synopsis of the family Formicidae of Taiwan (Insecta: Hymenoptera). Research Bulletin of Kanto Gakuen University. Liberal Arts 17:81-266.
 * Terayama M., S. Kubota, and K. Eguchi. 2014. Encyclopedia of Japanese ants. Asakura Shoten: Tokyo, 278 pp.
 * Terayama, M. 1984. A new species of the army ant genus Aenictus from Taiwan (Insecta; Hymenoptera; Formicidae). Bull. Biogeogr. Soc. Jpn. 39: 13-16
 * Terayama, M. 2009. A synopsis of the family Formicidae of Taiwan (Insecta; Hymenoptera). The Research Bulletin of Kanto Gakuen University 17: 81-266.
 * Xu Z. 1994. A taxonomic study of the ant subfamily Dorylinae China (Hymenoptera Formicidae Ponerinae). Journal of Southwest Forestry College 14(2): 115-122
 * 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.