Aenictus boltoni, Gómez, 2022

Gómez, Kiko, 2022, A revision of the Afrotropical species of the Dorylinae ant genus Aenictus (Hymenoptera: Formicidae) based on the worker caste, Belgian Journal of Entomology 124, pp. 1-86 : 49-51

Aenictus boltoni sp. nov.

Zoobank: 76FBB922-6240-4364-BFF6-E17EE57DFF38

( Figs 32 A–D , 33 )

Holotype worker: NIGERIA: • Gambari 14/08/1969 (Bolton, B.) (1w) [ NHMUK012849298 ] BMNH .

Paratype workers: • same data, (2w each) [ NHMUK012849294 to NHMUK012849297 ] BMNH; same data (1w) [ NHMUK012849327 ] BMNH .

DIAGNOSIS. This species can be separated from the rest of the mariae complex species as dorsopropeum is mainly smooth (reticulated in A. hitai sp. nov.) and does not present the lateropropodeal pubescence characteristic of A. steindachneri. Separation from A. mariae minors as in the following table.

This species does not present a marked allometry (CSR 114) as the other three species (CSR 131 for A. mariae and>170 for A. hitai sp. nov. and A. steindachneri) and seems to have a smaller maximum size (HW <0.42 against 0.52 for mariae or 0.69 for steindachneri), though this can be due to a lack of material as the four species have similar minimum sizes (HW> 0.28 for hitai and>0.36 for the rest).

Also, this species seems to be distributed in West Africa, while the other three inhabit Southern and Western Africa and their distribution don’t seem to overlap.

DESCRIPTION ( Fig. 32 A–D ). WORKER. HL: 0.46 [0.43-0.49]; HW: 0.37 [0.35-0.40]; SL: 0.25 [0.22-0.27]; WL: 0.64 [0.57-0.71]; PL: 0.16 [0.14-0.17]; PH: 0.11 [0.10-0.13]; PPL: 0.12 [0.11- 0.14]; PPH: 0.11 [0.10-0.13]; CS: 0.42 [0.39-0.44]; CI: 80 [75-82]; SIL: 53 [51-56]; SIW: 67 [63-71]; WL/HW: 171 [164-181]; PI: 138 [127-145]; PPI: 113 [107-127]; CSR: 114; (n=12).

Monomorphic. Scapes short, just reaching the median line of the head when laid back (SIL~0.49). Funicular segments wider than long, the subapical quadrate, apical two and a half times longer than wide. Head elongated (CI~79) with convex lateral sides and slightly widest at the middle; occipital line straight with rounded corners. Frontal carinae small, not surpassing the torulus and fused between the antennal sockets. Frontal ridges developed distally and projecting over the clypeus in frontal view. Long, sharp apical tooth followed by an 4–5 smaller denticles, sometimes very eroded. Clypeus reduced to a row of 5 small conical denticles below the antennal insertions and much smaller, almost invisible minute denticles laterally.

Propodeum and mesonotum weakly convex, propodeum flat; mesopropodeal suture clearly demarcated and visible both in lateral and dorsal views; mesonotum in dorsal view not forming a continuous surface with propodeum. Transverse mesopleural groove present. Mesometapleural suture present but very weak. Propodeal declivity flat; posterodorsal and posterolateral ridge absent.

Petiole sessile with anterolateral ridges present but very weak, anterodorsal, posterior and dorsolateral ridges absent. Petiolar dome low and rounded, subelliptical.

Postpetiole with anterior and posterior vertical faces and horizontal dorsal surface, antero and postero dorsal angles right and rounded. Subpetiolar process small, elliptical with a lamella varying in size from minute to clearly developed, facing anteriorly.

All body surfaces smooth and shining except for meso and metapleurae, petiole and postpetiole variable from alutaceus smooth in minima workers to the most common shagreenatereticulated; dorsal surfaces of petiole and postpetiole from smooth to weakly shagreenate; mandibles shagreened. Overall colour light brown with some individuals yellowish brown.

Whole body except propodeal dorsum covered with short from erect to decumbent small white setae. Dorsum of propodeum bare except for its anterior and posterior borders. The length of the longer setae as petiolar height; setae on dorsal surface of head directed upwards; lateral sides of head with erect setae; scapes with scattered decumbent to semierect setae, shorter than scape width. No pubescence noted.

DERIVATIO NOMINIS. The species name boltoni is Latinized noun in the genitive case, dedicated to Dr. Barry Bolton, who encouraged me to revise this genus and has always been extremely kind and helpful in my Afrotropical adventure.

OTHER MATERIAL EXAMINED. GHANA: • Mole G. Res. 13/08/1971 (Gotwald) (2w) [ NHMUK012849269 ] BMNH . IVORY COAST: • Lagunes, Lamto Scientific Reserve , 6.21508, -5.01844 09/07/2003. Pitfall (Kolo, Y.) (2w) [ KY0087CI ] YKPC .

DISTRIBUTION. West Africa, known from Ivory Coast to West Nigeria ( Fig. 33 ).

Figures

Fig. 32. Aenictus boltoni sp. nov., holotype (NHMUK012849298). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 33. Distribution of A. boltoni sp. nov.