Aenictus asantei

This species is probably a column raider and was found collecting immatures of a Pheidole species in coastal scrub and grassland habitat.

Identification
Diagnosis. The long mandibles crossing one over the other when closed and the presence of some irregular longitudinal rugulae over mesopleurae and propodeum makes this species unmistakable. Its overall size, hairy propodeum and habitus could at first glance resemble A. eugenii, but both can be easily distinguished with the cited mandibular characters.

Distribution based on Regional Taxon Lists
Afrotropical Region: Ghana, Nigeria.

Biology
Campione et al. (1983) - Behavioral observations on A. asantei were published previously (Gotwald 1976). The species (species A in Gotwald [1976]) was observed on four occasions (colonies GC-027, GC-035, GC-037, GC-047) in coastal scrub and grassland at Legon, Ghana, and once (colony GC-049) crossing a path between plots of cocoa, Theobroma cacao L., in the moist, semideciduous forest re­gion at Jukwa, Ghana. All five colonies were collected in heavily cultivated habitats. The four colonies found at began, the type-locality, were in columns moving near or in plots planted with cassava, Manihot esculenta Crantz, in the University of Ghana farm system.

A. asantei is probably a column raider (a column raid consists of a system of branching columns that usually terminate in small groups of advancing workers engaged in foraging activities), although on two occasions (colonies GC-035 and GC-037) the workers were traveling in a series of anastomosing columns that merged to form a single base column, reminiscent of the swarm raiding patterns of the driver ants of the army ant genus Doryus. In these two cases, the workers were traveling unidirectionally toward the base column, presumably toward the colony nest. The base columns varied from one to four workers in width, and some workers in each carried prey. Each trunk column entered a hole in the soil. The column of colony GC-037 was lined on both sides with clustered workers for the last 10 cm before the column made its subterranean descent. Colonies GC-027 and GC-049 were each observed as columns consisting of a single file of workers. The prey collected from colony GC-037 consisted of immature forms of the ant Pheidole sp. and included 24 worker pupae and 3 larvae. Although colony GC-047 was emigrating, several workers carried prey, all adults of Pheidole. The prey items included one queen, two workers, three worker heads, and one mesosoma.

The emigrating column of colony GC-047 was discovered at 0950 h. A detailed description of the emigration can be found in Gotwald (1976).

Nomenclature

 * . Aenictus asantei Campione, Novak & Gotwald, 1983: 873, 7 figs. (w.q.) GHANA.
 * Type-material: holotype worker, paratype workers (number not stated), 1 paratype queen.
 * Type-locality: holotype Ghana: University of Ghana, Legon, 27.vi.1971, GC-047, on cultivated land (B.M Campione, et al.); paratypes with same data.
 * Type-depositories: MCZC (holotype); BMNH, MCZC, MNHN, ROMT (paratypes).
 * Status as species: Bolton, 1995b: 58.
 * Distribution: Ghana.

Description
Worker, composite  description. Habitus as in Fig.A and  B;  total  length  3.47-3.89  mm; head,  alitrunk, waist, and gaster dark reddish brown to reddish orange;legs and antennae orange-brown to yellow-orange; bul­lae of metapleural glands yellow, especially conspicuous in darkly pigmented individuals. Pilosity moderately abundant, consisting of erect to suberect setae. Head as in Fig. JC; head length 0.63-0.77 mm; head width 0.63-0.72 mm; cephalic  index  (HW/HL  X   100) 93.5-107.9. Head glossy,  without  obvious  punctures; parafrontal  ridges  (elevated  lines  extending  longitudi­nally from clypeus laterad to the antenna! fossae) well developed,  each terminating  in a minute  spine. Frontal carinae expanded  anteriorly  to  form  thin  flanges  pro­jecting dorsally; clypeus bearing distinct serial teeth (Fig. lC and 3 A and B); occipital collar present; eyes absent. Antenna  10-segmented,  scape  length  0.54-0.63  mm. Mandible  flattened,  linear,  striolate,  with  sharp  apical tooth;  subapical  teeth  absent,  although  some denticles. may be present (Fig: 2B). Labrum bilobed with smoothly rounded median cleft (Fig. 2A); maxillary palpus two-segmented (Fig. 2C); lateral shoulder of stipes bearing three stout setae (Fig. 2C); stipes without transverse stipital groove; galea crown flattened,  invested  with numerous setae  (Fig.  2C);  maxillary  comb typical  (Fig.  2C); la­cinial  apex  bearing  numerous,  irregularly  placed,  fine. setae (Fig. 2C); labial palpus two-segmented (Fig. 20). Alitrunk as in Fig. I A and B and 3C; alitrunk length I. 10-1.26 mm; without conspicuous suturing. Pronotum glossy  except   for  anterior  dorsal   slope,  this  densely punctate; posterior two-thirds of alitrunk subopaque with well-developed  longitudinal rugae, especially on pleurae (Fig.  3C);  propodeal  junction  marked  by  sharply  pro­duced  ridge  extending  laterally  and  bordering  declivi­tous face of propodeum; declivitous face densely punctate. Petiole and  postpetiole  as  in  Fig. 10; waist (petiole plus postpetiole) length 0.63-.68 mm; petiole node length 0.29-0.36  mm,  width  0.18-0.27  mm;  postpetiolar  node length   0.27-0.36   mm,   width   0.20-0.27   mm. Waist opaque, densely punctate;  subpetiolar process  triangular with  rounded  apex, usually  directed  ventrally  or poste­riorly (Fig. 10).Gaster as in Fig. I A and B; gaster length 1.13-1.26 mm. Gaster glossy, lacking obvious punctures. Tarsal claws simple

Etymology
This species is named for the Asante people of Ghana.

References based on Global Ant Biodiversity Informatics

 * Campione B.M., J.A. Novak, W.H.Jr. Gotwald. 1983. Taxonomy and morphology of the West African army ant, Aenictus asantei n. sp. (Hymenoptera: Formicidae). Annals of the Entomological Society of America 76:873-883.