Aenictus binghami 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 : 25-29

Aenictus binghami Forel

( Figs. 33–34 )

Aenictus binghaniri (sic) Forel, 1900: 76 .

Aenictus binghami Forel : Bingham, 1903: 19; Wilson, 1964: 450, Figs 69–71; Bolton, 1995: 59; Jaitrong and Nabhitabhata, 2005: 11.

Aenictus (Typhlatta) binghami var. gatesi Wheeler, 1927: 42 (synonymized by Wilson, 1964: 450).

Types. Aenictus binghami: Six syntype workers (two pins, three workers on each) from Burma, Assam (MHNG, examined). One worker among them (top on a pin) is selected as the lectotype, the others as paralectotypes.

Measurements. Worker lectotype and paralectotypes (n = 6): TL 4.85–5.05 mm; HL 0.98–1.03 mm; HW 0.90–0.95 mm; SL 0.93–0.95 mm; ML 1.63–1.73 mm; PL 0.35–0.38 mm; CI 88–95; SI 100–105.

Redescription of worker (lectotype and paralectotypes). Head in full-face view slightly longer than broad, with sides convex and posterior margin almost straight; occipital margin bearing a carina. Antennal scape relatively long, but not reaching the posterolateral corner of head; antennal segments II–X each longer than broad; II almost as long as each of III–IV. Frontal carina short, a little extending beyond the level of the posterior margin of torulus.

Parafrontal ridge almost absent or very weak. Anterior margin of clypeus convex, bearing 6–7 denticles. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth, 6–7 denticles, and a medium-sized basal tooth; basal margin sinuate with a series of 3–4 ill-defined denticles. Promesonotum in profile convex dosally and sloping gradually to metanotal groove; propodeum in profile with its dorsal outline almost straight or feebly convex; propodeal junction obtusely angular; declivity of propodeum shallowly concave, encircled with a rim. Petiole distinctly longer than high, elevated posteriorly; subpetiolar process well developed and triangular, its apex directed downward and backward; postpetiole almost as long as petiole, with its node convex dorsally.

Head entirely smooth and shiny. Antennal scape microreticulate and subopaque, slightly shiny. Mesosoma entirely microreticulate and opaque, except for a very small patch on pronotum which is feebly shiny; reticular diameters on pronotum larger than elsewhere. In addition, mesonotum bearing a few irregular longitudinal rugae. Petiole punctate and opaque; postpetiolar dorsum smooth and shiny; lateral face shagreened with smooth and shiny interspaces. Femora entirely microreticulate except for basal portion micropunctate; tibiae microreticulate.

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 Prov., Nho Quan Dist., Cuc Phuong N.P. 11 VIII 1998, Sk. Yamane leg., VN 98-SKY-24 ( SKYC, THNHM); Ha Ta Prov., Ba Vi N.P., 13 XI 1999, K. Eguchi leg., Eg99- VN-134 ( SKYC, THNHM); same loc., 800 m alt., 21 IV 2002, K. Eguchi leg., Eg02-VN-068 ( SKYC, THNHM); Ban Om, Pu Hoat, M. Nghe An, 400 m alt. 22 XI 1999, T. V. Bui leg., code-012 ( SKYC, THNHM); same loc., 750 m alt. 2 XII 1999, T. V. Bui leg., code-015 ( SKYC, THNHM); Nghe An, Pu Mat N.P., Khe Kem, 200–350 m alt. 17 III 2006, K. Eguchi leg., Eg 17iii06-21 ( SKYC); Lao Cai Prov., Van Ban Dist., Liem Phu, 300–650 m alt., 29 IX 2006, K. Eguchi leg., Eg 29ix06-20 ( SKYC). LAOS: Vientiane, Pak Ngum dist., Phang Dang Village, MDF., 248 m alt., 12 VI 2010, W. Jaitrong leg., WJT10- LAO 15 ( THNHM); same loc., 467 m alt., 13 VI 2010, W. Jaitrong leg., WJT10- LAO 18 ( SKYC, THNHM). THAILAND: N. Thailand, Chiang Mai Prov., Doi Ang Khang, 17 VIII 2001, R. Phoonjampa leg. THNHM-I2002-3277 ( THNHM); N. Thailand, Chiang Mai Prov., Doi Suthep-Pui, Secondary forest, Pitfall trap, VII 2008, S. Sonthichai leg., WJT08-10 ( AMK, SKYC, THNHM); N. Thailand, Chiang Mai, Doi Inthanon, 750 m alt., 20 VIII 1998, Sk., Yamane leg., TH98-SKY-26 ( SKYC); N. Thailand, Chiang Mai Prov., Mae Tang Dist., Haui Prachao, HEF, 6 IX 2000, W. Jaitrong leg., WJT00- HPC 01 ( AMK, SKYC, THNHM); N. Thailand, Chiang Mai Prov., Doi Chiang Dao, 9 VI 2001, K. Eguchi leg., Eg01-TH-149 ( SKYC); same loc., 3- IV-2005, Sk. Yamane leg., TH05-SKY-71 ( SKYC); N. Thailand, Nan Prov., Sri Nan, MDF, 30 XI 2006. N. Chantarasawat leg., THNHM-I2007-1858 ( THNHM); N. Thailand, Tak Prov., near Myanmar border, Thung Yai, 4 I 1999, W. Jaitrong leg. ( AMK, SKYC, THNHM); N. Thailand, Pitsanulok Prov., Thung Salang Luang, 17 IX 1997, W. Jaitrong leg., WJT97- TSLL 02 ( AMK, SKYC, THNHM); same loc., Savanna forest, 15 X 1998, W. Jaitrong leg., THNHM-I2002-3278 ( AMK, THNHM); W. Thailand, Kanchanaburi Prov., Maeklong Watershed Research Station, 29 XI 2003, Sk., Yamane leg., TH03-SKY-144 ( SKYC); NE. Thailand, Loei Prov., Phu Luang, 14 V 2007, S. Hasin leg., SH07-TH-35 ( AMK, SKYC, THNHM); same loc., 11 IV 2008, W. Jaitrong leg., WJT08-PL03 ( AMK, SKYC, THNHM); NE. Thailand, Chaiyaphum Prov., Phu Kheao, 30 I 1999, W. Jaitrong leg., WJT99- TH069 ( AMK, SKYC, THNHM); same loc., Agriculture Area, 30 I 1999, W. Jaitrong leg., WJT99-TH050 ( AMK, SKYC, THNHM); NE. Thailand, Nakhon Ratchasima Prov., Sakhaerat, 17 IV 2001, W. Jaitrong leg., WJT01- DC01 ( AMK, SKYC, THNHM); same loc., 15 IX 2001, W. Jaitrong leg., WJT01-TH29 ( AMK, SKYC, THNHM); same loc., 13 IX 2000, W. Jaitrong leg., WJT00-SKR01 ( AMK, SKYC, THNHM); NE. Thailand, Nakhon Ratchasima Prov., Wang Nam Kheao Dist., 16 VIII 2009, W. Jaitrong leg., WJT09-TH2211 ( AMK, SKYC, THNHM); E. Thailand, Chanthaburi Prov., Pheao, EF, 22 XI 2003, S. Hasin leg., WJT03-21 ( AMK, SKYC, THNHM); E. Thailand, Chachoengsao Prov., Khao Ang Reu Nai, 19 XI 2003, W. Jaitrong leg., WJT03-TH300 ( SKYC, THNHM); same loc., 26 XI 2004, W. Jaitrong leg., WJT04-TH299 ( AMK, SKYC, THNHM); same loc., DEF, 20 VIII 2003, W. Jaitrong leg., WJT03-TH-02 ( AMK, SKYC, THNHM); same loc., Lumchangwat, 27 X 2002, W. Jaitrong leg., THNHM-I03-3431 ( AMK, SKYC, THNHM); same loc., 20 VIII 2003, W. Jaitrong leg., THNHM- I03 -3567 ( THNHM); same loc., 27 X 2002, W. Jaitrong leg., THNHM-I03-3494 ( AMK, SKYC, THNHM); same loc., 28 VI 2003, W. Jaitrong leg., THNHM-I03-3296 ( SKYC, THNHM); same loc., Khao Takrup, 29 VI 2003, W. Jaitrong leg., THNHM-I03-3401 ( THNHM); E. Thailand, Sakhao Prov., Pang Sida, 23 VIII 2006, W. Jaitrong leg., WJT06-11 ( SKYC, THNHM); same loc., 30-V-2006, W. Jaitrong leg., WJT06-E381 ( THNHM); E. Thailand, Chanthaburi Prov., Khao Soi Dao, 4 VI 2001, K. Eguchi leg., Eg01-TH-061 ( SKYC); E. Thailand, Chonburi Prov., Muang Dist., Khao Kheao, Chan Tatean Waterfall, 4 VIII 2009, W. Jaitrong leg., WJT09-TH2000 ( AMK, THNHM); S. Thailand, Nakhon Si Thammarat Prov., Khao Nan, Khlong Khai, 26 XI 2006, W. Jaitrong leg., WJT06-TH641 ( AMK, SKYC, THNHM); S. Thailand, Trang Prov., Palian Dist., Rubber plantation, 29 XI 1999, W. Jaitrong leg., WJT99-TH45 ( AMK, SKYC, THNHM).

Distribution. Vietnam, Laos, Myanmar, and Thailand ( Fig. 63 ).

Bionomics. Wilson (1964), based on Dr Schneirla’s notes, reported that A. binghami was found in dry tropical evergreen forest with moderate sub-humus moisture, under moderate cover. According to our observations, it inhabits highly varied habitats such as primary seasonal forest (hill evergreen forest, dry evergreen forest, mixed deciduous forest, and savanna), secondary forest, and open areas and plantations near the forest edge. A bivouac, including a foundress queen, was found under a stone during night in Cuc Phuong National Park, Vietnam ( VN 98- SKY-24).

We observed this species preying on other ants such as Anoplolepis ( Thailand, WJT06-E381, WJT09- TH2000), Camponotus ( Vietnam, Eg99-VN-134; Thailand, WJT06-E381, TH01-SKY-39, WJT03-TH300, THNHM-I03-3401), Cerapachys ( Thailand, TH98-SKY-26), Leptogenys ( Thailand, WJT99-TH45), and Polyrhachis ( Laos, WJT10- LAO 15; Thailand, TH05-SKY-71, WJT06-E381, THNHM-I03-3401, THNHM-I03-3567).

Remarks. A. binghami is similar to A. siamensis in having an entirely sculptured mesosoma but is consirerably larger than the latter (HW 0.90–0.95 mm vs. 0.63–0.70 mm). The entire pronotum is finely and densely reticulate and opaque in A. binghami , while it is very superficially reticulate and somewhat shiny in A. siamensis . Femora of all legs are rather smooth in A. siamensis , but microreticulate in A. binghami .

The specimens collected from Vietnam, and the northern, western, and southern parts of Thailand agree well with the type series from Myanmar, but those collected from Laos, and northeastern and eastern parts of Thailand differ slightly from the type series in the postpetiole being more distinctly microreticulate than in the latter. We did not examine the type series of Aenictus (Typhlatta) binghami var. gatesi Wheeler from Myanmar. According to Wilson (1964) they are slightly smaller than typical workers of A. binghami . As we need more material to settle the status of this form, at this moment we follow Wilson (1964), who synonymized it with A. binghami .

According to the collecting sites and previous literature ( Zhou & Chen, 1999; Zhou, 2001 for South China; Yamane et al., 2003; Eguchi et al., 2005 for N. Vietnam), A. binghami is mainly distributed in continental Southeast Asia north of the Isthmus of Kra ( Vietnam, Laos, Myanmar, and Thailand), and is rarely found in Sundaland (southern Thailand, south of the Isthmus of Kra). So far the southernmost latitude of the range of this species is at Trang Province (ca. 400 km south of the Isthmus of Kra) ( Jaitrong & Ting-Nga, 2005).

Figures

FIGURES 33 – 37. Workers of Aenictus laeviceps group. 33 – 34, A. binghami, lectotype; 35 – 37, A. siamensis sp. nov., holotype. 33, 36, Head in full-face view; 34, 37, habitus in profile; 35, 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.