Aenictus parahuonicus, Jaitrong, Weeyawat & Yamane, Seiki, 2011

Jaitrong, Weeyawat & Yamane, Seiki, 2011, Synopsis of Aenictus species groups and revision of the A. curra x and A. laeviceps groups in the eastern Oriental, Indo-Australian, and Australasian regions (Hymenoptera: Formicidae: Aenictinae), Zootaxa 3128, pp. 1-46 : 19-21

Aenictus parahuonicus sp. nov.

( Figs. 17–19 )

Types. Holotype. Worker from S. Thailand, Trang Prov., Yan Takhao Dist., Thung Khai Botanical Garden, 9 VIII 2009, W. Jaitrong leg., WJT09-TH2007 (THNHM). Thirty-five paratype workers, same data as holotype (AMK, BMNH, MCZC, MHNG, SKYC, THNHM).

Measurements. Holotype and paratype workers (n = 8): TL 3.85–4.25 mm; HL 0.80–0.93 mm; HW 0.70–0.85 mm; SL 0.60–0.73 mm; ML 1.27–1.73 mm; PL 0.30–0.35mm; CI 86–92; SI 83–87.

Description of worker (holotype and paratypes). Head in full-face view subrectangular, slightly longer than broad, with sides feebly convex and posterior margin almost straight; occipital carina often evanescent medially. Antennal scape relatively short, extending only 2/3 of head length; antennal segments II–X each longer than broad; II almost as long as each of III–VI. Frontal carina short, slightly extending beyond the level of posterior margin of torulus. Parafrontal ridge essentially absent. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth and 6 denticles; basal margin sinuate with a series of ill-defined denticles. Mesosoma relatively elongate and stout; promesonotum in profile convex dorsally and sloping gradually to metanotal groove. Propodeum in profile with feebly convex dorsal outline; propodeal junction rounded; declivity of propodeum feebly convex, with blunt lateral carinae but not demarcated basally by a transverse carina; area below propodeal spiracle distinctly impressed; opening of propodeal spiracle clearly circular with its diameter about 2.5 times as long as diameter of postpetiolar spiracle. Petiole clearly longer than high, with its dorsal outline convex; subpetiolar process well developed, triangular or roundly produced anteriorly, with its ventral outline feebly convex. Postpetiole shorter than petiole and almost as long as high, with its dorsal outline convex.

Head including mandible entirely smooth and shiny; antennal scape dorsally smooth but ventrally sculptured. Pronotum smooth and shiny except for the anterior portion which is punctate; mesonotum smooth and shiny; mesopleuron wrinkled and macroreticulate; metapleuron and propodeum punctate but the punctation weaker than in mesopleuron. Petiole with dense micropunctures except for a small area on dorsal surface which is smooth and shiny. Postpetiole smooth and shiny except for anterior and lateral portions which are punctate. Legs smooth and shiny.

Head with some short standing hairs in addition to two long hairs on vertex; mesosoma with relatively sparse standing hairs mixed with sparse suberect short hairs over the surface; length of the longest pronotal hair 0.35–0.40 mm. Entire body dark reddish-brown, with a relatively large typhlatta spot on occipital corner.

Non-type material examined. VIETNAM: Ninh Binh, Cuc Phuong N.P., 9 VI 2005, K. Eguchi leg., Eg 09vi05-01 ( SKYC); same loc., 11 VIII 1998, H. Okido leg. ( SKYC); Vinh-Phuc Prov., Tam Dao N.P., 900 m alt., 10 XI 1999, H. Okido leg., VN 99-HO-057 ( SKYC); Nghe An Prov., Que Phong Dist., Thong-Thu com., Ban loc, 9 IV 1999, T. V. Bui leg. ( SKYC, THNHM); An Prov., Pu Hoat, Nghe, VI 1999, T. V. Bui leg., VN 9902 ( SKYC, THNHM). LAOS: Vientiane, Naxaythong Dist., Sivilay Village, Plantation, 9 VI 2010, W. Jaitrong leg., WJT10- LAS10 ( THNHM); THAILAND: NE. Thailand, Chaiyaphum Prov., Phu Kheao, 11 VII 1998, W. Jaitrong leg., WJT98-TH052 ( AMK, THNHM); same loc., 27 III 1999, W. Jaitrong leg., WJT99-TH054 ( AMK, THNHM); NE. Thailand, Nakhon Ratchasima Prov., Khao Yai, 31 V 2000, Sk. Yamane leg. ( SKYC); E. Thailand, Chachoengsao Prov., Khao Ang Reu Nai, 26 X 2002, W. Jaitrong leg., THNHM-I02-3488 ( SKYC, THNHM); same loc., 17 I 2004, W. Jaitrong leg., WJT04-CS009 ( SKYC, THNHM); E. Thailand, Chanthaburi Prov., Khao Soi Dao, 19 VII 1997, Sk. Yamane leg., TA970719-01 ( SKYC, THNHM).

Etymology. The specific name is based on the close affinity of this species to A. huonicus .

Distribution. Vietnam, Laos, Thailand, and Malay Peninsula (S. Thailand) ( Fig. 23 ).

Bionomics. A. parahuonicus is widespread, distributed from northern Vietnam to southern Thailand (Sundaland). This species carries out its raids and emigrations on the surface in highly varied situations, from open areas, plantation, and light cover to deep forest during the day as well as at night. We observed this species preying on ants of the genera Pheidologeton and Dolichoderus ( Thailand, TA970719-01) and also on termites (type series, WJT09-TH2007).

Remarks. A. parahuonicus is very similar in general appearance to A. currax , A. diclops , A. huonicus , A. pfeifferi , and A. wayani . However, it is easily distinguished from the other species of this group by having the declivity of propodeum not demarcated from dorsum by a carina (bluntly margined laterally), while in the others it is encircled with a distinct rim.

All the Thai specimens cited as A. huonicus in Jaitrong and Nabhitabhata (2005) were reidentified as A. parahuonicus . Aenictus sp. 28 in Yamane et al. (2003) is also A. parahuonicus .

Figures

FIGURES 17 – 22. Workers of Aenictus currax group. 17 – 19, A. parahuonicus sp. nov., holotype; 20 – 22, A. wayani sp. nov, holotype. 17, 21, Head in full-face view; 18, 22, habitus in profile; 19, 20, dorsal view of body.

FIGURES 23 – 25. Distribution of Aenictus currax group. 23, A. cornutus and A. parahuonicus sp. nov.; 24, A. gracilis; 25, A. glabrinotum sp. nov., A. pfeifferi, and A. wayani sp. nov.