Aenictus weissi Santschi, 1910

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 : 78-81

Aenictus weissi Santschi, 1910

( Figs 61 A–D , 62 )

Aenictus weissi SANTSCHI, 1910: 354 , fig. 2 (w.)

Syntype, GABON (as Congo fr.): Gomba (A. Weiss) (1w) [ CASENT0911444 ] NHMB [Examined ]; Syntype, GABON, 1914 (F. Faure) (1w) MHNG [Examined].

Aenictus weissi Santschi ; SANTSCHI, 1920: 9 (Q.) (Cited, but not described).

DIAGNOSIS. The lack of a developed subpetiolar process and the presence of a horizontal propodeal ridge separates this species from the rest in the rotundatus complex except for A. nyuyi sp. nov., but both species are separable by the shorter scapes (SIL<75 against SIL>80).

Type material is referred to Congo Francaise, Gomba. I’m assuming this location refers to Gomba city in Gabon. Although different catalogues cite the queen caste as described in SANTSCHI (1920), this reference only cites the species from Gabon, so the queen remains undescribed.

The specimen from Gr. Batanga (Cameroon) labelled as type has two identification labels: Aenictus weissi wasmanni Santschi and Aenictus rixator v. congolensis . Two more workers with the same data seem to belong to the same series and are labelled as Aenictus weissi wasmanni Santschi. This material is referred here to A. weissi , as A. weissi wasmanni seems to be unpublished.

DESCRIPTION ( Fig. 61 A–D ). WORKER. HL: 0.65 [0.58-0.76]; HW: 0.53 [0.45-0.64]; SL: 0.45 [0.41-0.51]; WL: 0.99 [0.85-1.16]; PL: 0.24 [0.20-0.28]; PH: 0.18 [0.12-0.23]; PPL: 0.19 [0.16- 0.24]; PPH: 0.15 [0.11-0.18]; CS: 0.59 [0.52-0.70]; CI: 81 [75-87]; SIL: 69 [66-72]; SIW: 85 [77-93]; WL/HW: 186 [171-200]; PI: 134 [114-191]; PPI: 127 [111-163]; CSR: 134; (n=22).

Scapes moderately long, reaching three quarters of the head when laid back (SIL~70). Funicular segments 1 and 2 longer than wide, 3–7 subquadrate, apical twice and a half times longer than wide.

Head rectangular, longer than wide (CI ~ 80), convex laterally and widest at the middle, occipital line straight, ventrolateral margin not developing ventrally. Mandibles with a long, sharp apical tooth and 5–8 smaller triangular denticles. Frontal ridges present, not projecting anteriorly and not fused between sockets, intersection between anterior and vertical ridges elevated into a triangular lobe; parafrontal ridges weakly developed but present, in lateral view forming a small rounded triangle; in basal view parafrontal ridges about the same size than frontal ridges; both structures not extending from the antennal sockets.

Transverse mesopleural groove and mesometapleural suture present but not deeply impressed. Propodeal declivity slightly convex, encircled by a well-developed ridge, wider dorsally than laterally and projecting as a shelf in dorsal view.

Petiole with anterolateral and anterodorsal ridges well developed, dorsolateral absent. Petiolar dome with an anterior face sloping at 45 degrees approximately, anterodorsal angle obtuse, posterodorsal angle right, both rounded. Postpetiole with an anterior and posterior vertical faces and dorsal surface horizontal, but smaller than petiolar anterodorsal surface; anterodorsal angle obtuse, posterodorsal right, both domes without carinae or ridges of any kind. Subpetiolar process small, with an anterior face vertical or slightly anteriorly oriented, the rest shaped as a quarter of ellipse and without lamellae.

Head, scapes, pronotum, mesonotum, dorsopetiole and dorsopostpetiole, legs and gaster glassy smooth. Mesopleurae, metanotum and propodeum strongly reticulated. Lateropetiole and lateropostpetiole from alutaceus to reticulated. Some (4–5) horizontal rugulae present on metapleurae and anterior half of lateropropodeum. 1–2 horizontal rugulae may continue above the propodeal spiracle and on to the metapleural lobes. Overall colour light to dark brown, darker on head and mesosoma.

Whole body with sparse long decumbent to semierect white setae, including head, scapes and legs. Dorsum of propodeum bare except for its anterior and posterior borders. The length of the setae comparable to petiole height. No pubescence noted.

OTHER MATERIAL EXAMINED. CAMEROON: • Sud, P. N. Campo , 43.3 km 108° ESE Campo 290 m, 2.2825, 10.20617 04/07/2000. MW 50 sample transect, 5m (B.L.Fisher). rainforest (1w), sifted litter (leaf mold, rotten wood) [ CASENT0746806 ] CASC • Sud-Ouest, Mabete , Victoria Div. , 4.01667, 9.21667 24/05-07/06/2000 (B. Malkin) (2 pins, 3w) [ CASENT0810232 , CASENT0810233 ] CASC • Gr. Batanga 07/1912 ( Schwab ) (1w) [ CASENT0911445 ] NHMB • same data (2 pins, 1w each) [ CASENT08400035 , CASENT0911445 ] NHMB • Cameroon, Gr. Batanga ( Schwab ) (2w) Coll. Forel MHNG • Minko Meyos, 15 km S Yaoundé 03/1997 (Mercier, J. L.). Mango (4 pins, 3w each) [ NHMUK012849290 to NHMUK012849293 ] BMNH • Yaoundé 23/03/1989 (Dejean, A.) (5w) [ NHMUK012849289 ] BMNH • same data (5 pins, 3w each) [ NHMUK012849283 to NHMUK012849287 ] BMNH. DEMOCRATIC REPUBLIC OF CONGO: • Ituri, grotte Yoloha-firi, Mont Hoyo ( Park National Albert ) 1030m 25/07-09/08/1955 (P. Vanschytbroeck) (2 pins, 1w each) [ RBINSFOR002236 , RBINSFOR002237 ] RBINS. GABON: • Woleu-Ntem, 31.3 km 108° ESE Minvoul 600 m, 2.08, 12.40667 12/02/1998 (B.L.Fisher). rainforest (1w), ground forager(s) [ CASENT0317076 ] CASC • same data (3w) [ CASENT0317078 ], (3w) [ CASENT0317079 ]; (2w) [ CASENT0822358 to CASENT0822361 ]; (3w) [ CASENT0822362 to CASENT0822368 ]; (2w) [ CASENT0822369 ]; (3w) [ CASENT0822370 to CASENT0822373 ]; (2w) [ CASENT0822374 , CASENT0822375 ]; (1w) [ CASENT0822381 ]; (2w) [ CASENT0822382 ]; (3w) [ CASENT0822383 ]; (1w) [ CASENT0822384 , CASENT0822385 ]; (3w) [ CASENT0822386 to CASENT0822389 ]. GHANA: • Cocoa Research Institute ( Tafo ) 23/12/1991 (Belshaw, R.). Secondary Forest (1w), Leaf litter [ NHMUK012849288 ] BMNH • Tafo 20/02/1968 (Bolton, B.) (1w), Rotten log [ NHMUK012849273 ] BMNH • New Tafo C.R.I.G. 23/06/1979 (Gotwald, W.) (5 pins, 1w each) [ FMNH-INS 0000 053 880 , FMNH-INS 0000 053 881 and FMNH-INS 0000 053 996 to FMNH-INS 0000 053 998] FMNH • Pankese 30/09/1968 (Bolton, B.) (3 pins, 3w each), On cocoa [ NHMUK012849274 to NHMUK012849276 ] BMNH • Kumasi, Bobiri Forest Reserve , 6.69048, -1.33828 10/01/2019. Hand (Gomez, K.). Prim. unlog. For. (2w), ex. Rotten log [ KGCOL00583 ] KGPC. GUINEA: • Nzérékoré, Forêt vallée de Zié ( Mount Nimba ), 7.67333, -8.37267 24/04/2017. Monolithe (Kolo, Y.). Forest (1w) [ KY00119GUI ] YKPC • Nzérékoré, Transition Mt Leclerc ( Mount Nimba ), 7.67075, -8.41525 19/04/2017. Pitfall (Kolo, Y.) (1w) [ KY00121GUI ] YKPC • Nzérékoré, Valée de Zié (2) ( Nimba ) 1186m 14/11/2017. Canopy fogging (D. van der Spiegel). Sec. For. near river (1w), Covery 60% [ MRACFOR000762 ] MRAC. IVORY COAST: • Dené (Man) 09/03/1977 (I. Löbl). For. Litter near river (1w) [ MHNGENT000012639 ] MHNG. KENYA: • Western Province, Kakamega Forest , Bukhaywa 1573m, 0.34581, 34.84806 01/07/2004. pitfall trap (F. Hita Garcia). farWLand near forest edge (1w), ground [ CASENT0764141 ] FHGC • Western Province, Kakamega Forest , Yala Forest Fragment 1600m, 0.2025, 34.86833 01/05/2008. pitfall trap (M. Peeters). primary forest (1w), leaf litter [ CASENT0790572 ] FHGC • Western Province, Kakamega District, Ivakale 1650m, 0.36936, 34.8915 21/07/2007. winkler (G. Fischer). subsistence farWLand (1w), leaf litter [ CASENT0790573 ] FHGC. NIGERIA: • Black Pod Project (CRIN) 06/10/1975 (Taylor, B.) (1w), On cocoa [ NHMUK012849277 ] BMNH • Gambari 26/06/1969 (Bolton, B.) (1w), On cocoa [ NHMUK012849280 ] BMNH, • same data (2 pins, 1w each) [ NHMUK012849278 , NHMUK012849279 ] BMNH • Ibadan (IITA) 11/1987 (Noyes, J.) (2w), On cocoa [ NHMUK012849282 ] BMNH, same data (3w) [ NHMUK012849281 ] BMNH. RWANDA: • South. Prov., Coeb ( Huye ) 1700m, -2.61795, 28.95637. Hand (Dekoninck, W.). Ruderal (3w), For. ground [ KG05522 ] KGAC • same data (1w) [ KGCOL02097 ] KGAC • South. Prov., Herbarium ( Huye ) 1700m, -2.62013, 29.74133. Hand (Dekoninck, W.). Ruderal (1w), For. ground [ KGCOL02095 ] KGAC. UGANDA: • Bundibugyo, Semuliki National Park 701 m, 0.82199, 30.15919 18/08/2012 (B.L. Fisher et al.). rainforest edge (1w), ground forager(s) [ CASENT0317966 ] CASC • same data (1w) [ CASENT0317967 , CASENT0317968 ] CASC • Bundibugyo, Sempaya , SeWLiki NP 700m, 0.82987, 30.16558 18/08/2012. search (J. Longino). road/forest edge (11w, ethanol), column on ground [ JTL687068 ] JTLC • same series (3w) [ KGCOL00582 ] KGPC.

DISTRIBUTION. West and Central Africa, from Guinea in the West to the Kenyan Forest to the East ( Fig. 62 ).

Figures

Fig. 61. Aenictus weissi, worker (CASENT0317076). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 62. Distribution of A. weissi.