Aenictus minutulus Terayama et Yamane, 1989

Jaitrong, Weeyawat & Hashimoto, Yoshiaki, 2012, Revision of the Aenictus minutulus species group (Hymenoptera: Formicidae: Aenictinae) from Southeast Asia, Zootaxa 3426 (1), pp. 29-44 : 36-38

Aenictus minutulus Terayama et Yamane, 1989

( Figs 4 A–E, 7)

Aenictus minutulus Terayama et Yamane, 1989: 601 , figs 7–10.

Aenictus minutulus : Bolton, 1995: 60.

Types. Holotype and three paratype workers from Indonesia, Mentawai Is., Pulau Sipora, 28.VII.1985, Sk. & S. Yamane leg. ( MZB and SKYC; two paratypes examined) .

Measurements. Paratype workers (n = 2): TL 1.90–1.95 mm; HL 0.45 mm; HW 0.38–0.39 mm; SL 0.25–0.26 mm; ML 0.63 mm; PL 0.15–0.16 mm; CI 83–86; SI 67–68.

Non-type workers (n = 10): TL 1.7–2.40 mm; HL 0.43–0.53 mm; HW 0.33–0.48 mm; SL 0.23–0.33 mm; ML 0.55–0.75 mm; PL 0.14–0.20 mm; CI 76–90; SI 65–71.

Description of worker (paratypes). Head in full-face view rectangular, clearly longer than broad, with almost parallel sides and almost straight or weakly concave posterior margin. Antennal scape reaching midlength of head; antennal segment II longer than broad; III as long as broad; IV–VI each slightly broader than long; VII–IX each as long as broad and III slenderer than IV–VI; terminal segment longer than broad, 2.0 times as long as broad. Frontal carina very short, not extending beyond the level of posterior margin of torulus. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth, 1–2 denticles, and medium-sized basal tooth; basal margin with 3–4 small denticles. Mesosoma in profile almost straight dorsally; metanotal groove indistinct; metapleural gland bulla relatively small; distance between propodeal spiracle and metapleural gland bulla clearly longer than spiracular diameter ( Fig. 4 D). Propodeum in profile with straight dorsal outline; propodeal junction bluntly angulate; declivity of propodeum shallowly concave, seen from back distinctly convergent above, with lateral carinae, but not demarcated basally by a transverse carina. Petiole almost as long as high, with its dorsal outline convex; subpetiolar process large, subretangular, with anterior and posterior corners each acutely angulate. Postpetiole almost as long as petiole, its dorsal outline convex.

Head including mandible and antennal scape smooth and shiny; mesonotum and lateral face of propodeum microreticulate; remainder of mesosoma smooth and shiny. Dorsa of petiole and postpetiole smooth and shiny; lower 1/2 of lateral faces of petiole and postpetiole microreticulate and opaque. Legs entirely smooth and shiny.

Head and mesosoma dorsally with relatively dense standing hairs mixed with sparse short hairs over the surface; longest pronotal hair 0.10 mm long. Ground color light brownish yellow; antennae, legs and gaster yellow.

Non-type material examined. INDONESIA: West Sumatra, Mentawai Is., Pulau Sipora (same colony as holotype), 28.VII.1985, Sk & S. Yamane leg. ( SKYC); C. Java, Yogyakarta, Campus of Gajah Mada Universty (100 m alt.), 29.XII.2002, Sk. Yamane leg., JV02/03-SKY-23 ( SKYC, THNHM); W. Java, Cibinong, disturbed area, 26.XI.2009, Kei. Nakamura leg., CI09-KEI-001 ( SKYC, THNHM).

Distribution. Sumatra and Java (new record) ( Fig. 7 ).

Bionomics. This species is very probably sympatric with Aenictus sp.56 of WJT in at least Java. The type series and non-type material examined were collected from both primary and disturbed lowland rainforests.

Remarks. Aenictus minutulus is very similar in general appearance to A. changmaianus , and A. minimus . See under A. changmaianus for details.

Figures

FIGURE 4. Aenictus minutulus (A, B, C, E, paratype; D, non-type from W. Java). A, Head in full-face view; B, body in dorsal view; C, body in profile; D, propodeal junction, petiole and postpetiole in profile; E, mandible.

FIGURE 7. Distribution of the Aenictus minutulus group.