Aenictus brevipodus, Jaitrong & Yamane, 2013

Jaitrong, Weeyawat & Yamane, Seiki, 2013, The Aenictus ceylonicus species group (Hymenoptera, Formicidae, Aenictinae) from Southeast Asia, Journal of Hymenoptera Research 31, pp. 165-233 : 175-177

Aenictus brevipodus sp. n. Fig. 3A-C

Type material examined.

Holotype. VIETNAM: Worker from N. Vietnam, Lao Cai Prov., Van Ban Dist., Liem Phu (450-650 m alt.), 28.IX.2006, leg. K. Eguchi, Eg28ix06-10 (VNMN). Paratypes. Nine workers, same data as holotype (SKYC, THNHM).

Worker measurements

(Holotype and paratypes, n = 3). TL 3.00-2.85 mm; HL 0.60-0.58 mm; HW 0.58-0.50 mm; SL 0.40-0.38 mm; ML 1.00-0.95 mm; PL 0.25 mm; CI 90-96; SI 65-70.

Description of worker

(holotype and paratypes). Head in full-face view subrectangular, slightly longer than broad, sides weakly convex and posterior margin feebly convex; with head in profile occipital corner bearing a distinct carina. Antennal scape relatively short, not reaching 1/2 of head length. Frontal carina relatively long, extending beyond the level of posterior margin of torulus. Parafrontal ridge indistinct. Anterior clypeal margin strongly concave, lacking denticles and concealed by curved anterior extension of frontal carina. Masticatory margin of mandible with 4 teeth, including a large apical tooth; basal margin strongly concave. Maximum width of gap between anterior clypeal margin and mandibles 1.8-2.0 times as broad as maximum width of mandible. Promesonotum rather stout, weakly convex dorsally and sloping gradually to metanotal groove; metanotal groove distinct, deep; anepisternum demarcated from katepisternum by a shallow groove; mesopleuron clearly demarcated from metapleuron by a deep groove. Propodeum in profile with weakly convex dorsal outline; propodeal junction angulated, nearly right-angled; declivity of propodeum shallowly concave, and encircled with a distinct rim; metapleural gland bulla relatively large, its maximum diameter about 3.3 times as long as distance between propodeal spiracle and metapleural gland bulla. Petiole almost as long as high, with its dorsal outline convex; subpetiolar process generally very low, subrectangular with its anteroventral and posteroventral corners angulate, and margin between the corners almost straight. Postpetiole rounded, almost as long as petiole. Legs relatively short.

Head and gaster smooth and shiny; basal half of antennal scape densely microreticulate but apical half superficially microreticulate and shiny; mandible finely striate except along masticatory margin smooth and shiny. Pronotum smooth and shiny except for anteriormost portion reticulate; mesothorax densely reticulate; metapleuron reticulate, partly smooth and shiny; propodeum entirely reticulate, its dorsum somewhat shiny. Petiole and postpetiole entirely reticulate except dorsa smooth and shiny. Basal 1/3 of femora finely microreticulate, apical 2/3 smooth and shiny; basal half of tibiae microreticulate (but the reticulation weaker than on basal 1/3 of femora), apical half smooth and shiny.

Head and mesosoma dorsally with relatively dense standing hairs; longest pronotal hair 0.13-0.15 mm long. Body yellowish brown; antenna and mandible dark brown; legs yellowish brown except basal 1/3 of femora dark brown.

Etymology.

The specific name refers to the short legs, especially fore tibiae.

Distribution.

Vietnam ( Fig. 24B ).

Bionomics.

So far this species has been known only from the type locality in the lowland (450-650 m alt.).

Remarks. Aenictus brevipodus is similar to Aenictus doryloides Wilson, 1964, as they share the strongly concave anterior clypeal margin and basal margin of mandible ( Figs 3A and 28A ). However, Aenictus brevipodus is easily separated from the latter by the following characteristics: promesonotum weakly convex (mesosomal dorsum flat in the latter); metanotal groove distinct and deep (indistinct or almost absent in the latter).

Figures

Figure 3. Aenictus brevipodus (holotype). A Head in full-face view B body in dorsal view C body in profile.

Figure 24. Distribution of Aenictus ceylonicus group. A Aenictus formosensis, Aenictus fuchuanensis, Aenictus lifuiae B Aenictus brevipodus, Aenictus concavus, Aenictus thailandianus, Aenictus wiwatwitayai.

Figure 28. Aenictus doryloides (paratype). A Head in full-face view B body in profile C body in dorsal view; labels of paratype.