Aenictus hodgsoni Forel

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 : 35-36

Aenictus hodgsoni Forel

( Figs.49–50 )

Aenictus fergusoni var. hodgsoni Forel, 1901: 474 .

Aenictus fergusoni: Wilson, 1964: 462 (part); Bolton, 1995: 59 (part). Aenictus hodgsoni: Jaitrong et al., 2011: 321 (raised to species status).

Types. Aenictus fergusoni var. hodgsoni : Lectotype and five paralectotype workers from Burma [ Myanmar], Moulmain (MHNG, examined).

Measurements. Worker lectotype and paralectotypes (n = 6): TL 3.50–3.70 mm; HL 0.75–0.78 mm; HW 0.63–0.68 mm; SL 0.60–0.65 mm; ML 1.05–1.13 mm; PL 0.23–0.25 mm; CI 83–87; SI 96–100.

Redescription of worker (lectotype and paralectotypes). Head in full-face view slightly longer than broad, with its sides slightly convex and posterior margin almost straight; occipital margin bearing a narrow carina. Antennal scape relatively short, not reaching posterolateral corner of head; antennal segments II–X each longer than broad; II almost as long as each of III–VI. Frontal carina short, not extending beyond the level of posterior margin of torulus. Anterior margin of clypeus bearing several denticles. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth, 4–5 denticles, and a medium-sized basal tooth; basal margin lacking denticles. Promesonotum in profile convex dorsally; propodeum in profile with its dorsal outline almost straight; propodeal junction angulate, right-angled; area behind propodeal spiracle and above metapleural gland bulla impressed; declivity not distinctly margined dorsally and laterally, seen from back tapering above. Petiole almost as long as high, in profile its dorsal outline strongly convex; subpetiolar process well developed and triangular, its apex directed downward and backward; postpetiole almost as long as petiole.

Head entirely smooth and shiny. Mandible very finely striate except along masticatory margin. Antennal scape entirely microrecticulate. Pronotum smooth and shiny, its anteriormost portion punctate; mesothorax, metapleuron and lateral face of propodeum with dense punctures and several longitudinal rugae; dorsal face of propodeum essentially smooth and shiny. Petiole entirely smooth and shiny except for anteriormost portion punctate; postpetiole entirely smooth and shiny. Femora extensively superficially reticulate and shiny; tibiae very finely reticulate.

Head and mesosoma dorsally with relatively sparse standing hairs mixed with sparse short hairs over the surface; longest pronotal hairs 0.30–0.33 mm long. Entire body dark reddish brown. Typhlatta spot located anterior to occipital corner.

Non-type material examined. CHINA: Guangxi, Xing An County, Gao Zhai (300 m alt.), 15 IX 2000, K. Eguchi leg., Eg00-GNGX-010. HONG KONG: New Territory, Taipo Kau, X 2000, G. Barretto leg. ( SKYC, THNHM). VIETNAM: Vinh-phuc Prov., Tam Dao N.P., 900 m alt., 9 XI 1999, K. Eguchi leg., Eg99-VN-061 ( SKYC, THNHM); Ha Tai Prov., Ba Vi N.P., 400–600 m alt., 11 XI 1999, K. Eguchi leg., Eg99-VN-082 ( SKYC, THNHM); same loc., 400 m alt., 11 XI 1999, K. Eguchi leg., Eg99-VN-080 ( SKYC, THNHM); same loc., 600 m alt., 20-21 III 2005, T. V. Bui leg. ( SKYC); Ninh Binh Prov., Nho Quan Dist., Cuc Phuong N.P., 11 VIII 1998, H. Okido leg., VN 98-HO-024 ( SKYC); Thai Ngugen, Na Hau Village, My Yen Comm. Forest, 8 XI 2001, Sk. Yamane leg., VN 01-SKY-30 ( SKYC, THNHM); Nghe An Prov., Pu Hoat, V 1999, T. V. Bui leg., VN 9902 ( SKYC, THNHM); Nghe An Prov., Que Phong Dist., Thong-Thu Com., Ban Loc, 9 IV 1999, B.T. Viet leg. ( SKYC, THNHM); same loc., 700 m alt., 16 IV 1999, T. V. Bui leg. ( SKYC, THNHM); M. Nghe An Pu Hoat, Primary forest, 750 m alt., 22 XI 1999, T. V. Bui leg., code 0 12 ( SKYC, THNHM); Nghe An Prov., Pu Mat N.P., Near Forest Station, Pha Lai, 26 III 2006, K. Eguchi leg., Eg 26iii06-20 ( SKYC, THNHM). LAOS: Vientiane, Naxaythong Dist., Sivilay Village, Open Area, 9 VI 2010, W. Jaitrong leg., WJT10- LAO 11 ( AMK, THNHM). CAMBODIA: Ratanakin Prov., Viachey N.P., 6 X 2007, S. De Greef leg., SDG358 ( SKYC). THAILAND: N. Thailand, Chiang Mai Prov., Doi Phahom Pok, 27 V 2008, W. Jaitrong leg., WJT08-N16 ( AMK, SKYC, THNHM); N. Thailand, Chiang Mai Prov., Doi Ang Khang, 21 VIII 1998, Sk. Yamane leg., TH99-SKY-31 ( SKYC, THNHM); N. Thailand, Tak Prov., Thung Yai, DEF, 4 I 1999, W. Jaitrong leg. ( AMK, SKYC, THNHM); same loc., 25 V 2000, W. Jaitrong leg., WJT00-TY10 ( AMK, SKYC, THNHM); N. Thailand, Pitsanulok Prov., Thung Salang Luang, 10 X 1999, W. Jaitrong leg., WJT99-TH70 ( AMK, SKYC, THNHM); same loc., 17 IX 1997, W. Jaitrong leg., WJT97- TSLL 01 ( AMK, SKYC, THNHM); N. Thailand, Nan Prov., Doi Phuka, 800 m alt., 30 V 2004, W. Jaitrong leg., WJT04-N037 ( AMK, SKYC, THNHM); same loc., HEF, 29 V 2004, W. Jaitrong leg., WJT04-N001 ( AMK, SKYC, THNHM); NE. Thailand, Loei Prov., Phu Luang, 11 IV 2008, W. Jaitrong leg., WJT08-PL01 ( AMK, SKYC, THNHM); NE. Thailand, Chaiyaphum Prov., Phu Kheao, 30 I 1999, W. Jaitrong leg., WJT99-AG01 ( AMK, SKYC, THNHM); NE. Thailand, Nakhon Ratchasima Prov., Khao Yai, 700 m alt., 29 V 2000, Sk. Yamane leg., TH00-SKY-07 ( SKYC, THNHM); same loc., 27 X 2000, W. Jaitrong leg., WJT00-KY01 ( AMK, SKYC, THNHM); C. Thailand, Uthai Thani Prov., Ban Rai Dist., Kan Ma Kud Village, 18 VI 2010, W. Jaitrong leg., HKK 10-60-02 ( AMK, THNHM); E. Thailand, Sakhao Prov., Pang Sida, 29 V 2006, W. Jaitrong leg., WJT06-E379 ( AMK, SKYC, THNHM); same loc., 29 V 2006, W. Jaitrong leg., WJT06-E380 ( AMK, THNHM); E. Thailand, Chachoengsao Prov., Khao Ang Reu Nai, 29 V 2003, W. Jaitrong leg., WJT03-E380 ( AMK, SKYC, THNHM); same loc., Thatakiab Dist., 25 IV 2003, W. Jaitrong leg., WJT03-TH35 ( AMK, SKYC, THNHM); same loc., Sampran, 27 II 2003, W. Jaitrong leg., THNHM-I03-3045 ( AMK, SKYC, THNHM); same loc., DEF, Lumchangwad, 29 VII 2005, W. Jaitrong leg., WJT05-E210 ( AMK, SKYC, THNHM); E. Thailand, Chanthaburi Prov., Khao Soi Dao, Sk. Yamane leg. TH90-SKY-02 ( SKYC); E. Thailand, Chanthaburi Prov., Pong Nam Ron Dist., Khlong Tab Mak waterfall, 18 V 2008, W. Jaitrong leg., WJT08-E172 ( AMK, SKYC, THNHM); E. Thailand, Chanthaburi Prov., Pong Nam Ron Dist., Tabsai, Khao Kuar, 19 V 2008, W. Jaitrong leg., WJT08-E202 ( AMK, SKYC, THNHM); E. Thailand, Rayong Prov., Klaeng Dist., Khao Chamao-Khao Wong, 20 V 2008, W. Jaitrong leg., WJT08-E217 ( AMK, SKYC, THNHM); S. Thailand, Trang Prov., Palian Dist., plantation, 31 XI 1999, W. Jaitrong leg., WJT99-TH68 ( AMK, SKYC, THNHM); S. Thailand, Songkhla Prov., Khao Nam Khang, 25 VII 1997, Sk. Yamane leg. ( SKYC, THNHM). INDONESIA: W. Bali, Jelati Mendaya, Dusun PK, 6 V 1998, K. Eguchi leg., Eg98-BALI-737 ( SKYC, THNHM); W. Lombok, nr Semaya, Kopi house, 29 X 1998, K. Eguchi leg., Eg98-LMB- 1068 ( SKYC, THNHM).

Distribution. South China, Hong Kong, Vietnam, Laos, Cambodia, Myanmar, Thailand, Malay Peninsula (S. Thailand), Java, Bali, and Lombok ( Fig. 65 ).

Bionomics. A. hodgsoni is dominant in continental Southeast Asia, distributed from lowland to highland in varied forest types (hill evergreen forest, dry evergreen forest, evergreen rainforest, mixed deciduous forest, and savanna). This species is active both day and night. We found it preying on other ant species such as Anoplolepis gracilipes ( Thailand, WJT05-E210), Camponotus rufoglaucus ( Thailand, WJT06-379), Camponotus sp. ( Vietnam, VN 01-SKY-23), Iridomyrmex anceps ( Thailand, WJT06-380), Technomyrmex sp. (bicolor group) ( Vietnam, Eg 14vi05-08), and also on cockroaches ( Thailand, WJT06-379).

Remarks. Jaitrong et al. (2011) removed this species from synonymy with the closely related A. fergusoni based on the following characteristics: propodeum partly smooth and shiny in A. hodgsoni (entirely punctate in A. fergusoni ); propodeum in profile almost straight dorsally in A. hodgsoni (slightly convex in A. fergusoni ); declivity of propodeum above without transverse carina in A. hodgsoni (with a distinct transverse carina in A. fergusoni ). A. brevinodus and A. bodongjaya are also very similar to this species in having sparse standing hairs mixed with sparse short hairs on the head and promesonotum, and the mesopleuron being entirely densely sculptured. A. hodgsoni can be distinguished from A. bodongjaya by the femora being extensively superficially reticulate and shiny, the tibiae very finely reticulate (legs entirely smooth and shiny in A. bodongjaya ), and it can be separated from A. brevinodus by having the petiole slightly longer than high (clearly shorter than high in A. brevinodus ).

The specimens collected from Vietnam, Laos, Cambodia, and Thailand agree well with the type series from Myanmar, but in the single colony from Lombok, Indonesia, the workers have smooth and shiny femora, and the petiole is slightly smaller than in the type series. In the single colony from Bali, Indonesia, the workers have a reticulated petiole (entirely smooth and shiny in the type series).

All Thai and Vietnamese specimens cited as A. fergusoni in Yamane et al. (2003), and Eguchi et al. (2005), and Jaitrong and Nabhitabhata (2005) were reidentified as A. hodgsoni in the present study. A. laeviceps recorded from Vietnam by Radchenko (1993) is possibly A. hodgsoni (cf. Yamane et al. 2003).

Figures

FIGURES 44 – 50. Workers of Aenictus laeviceps group. 44, 45, A. breviceps, lectotype; 46 – 48, A. brevinodus sp. nov., holotype; 49, 50, A. hodgsoni, lectotype. 44, 46, 49, Head in full-face view; 45, 47, 50, habitus in profile; 48, dorsal view of body.

FIGURES 63 – 66. Distribution of Aenictus laeviceps group. 63, A. alticola, A. binghami, and A. fulvus sp. nov., A. luzoni; 64, A. bodongjaya sp. nov., A. breviceps, A. brevinodus sp. nov., and A. montivagus sp. nov.; 65, A. hodgsoni, and A. laeviceps; 66, A. sonchaengi sp. nov., A. rotundicollis sp. nov., and A. siamensis sp. nov.