Aenictus congolensis Santschi, 1911, 1964

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 : 60-61

Aenictus congolensis Santschi, 1911

( Figs 41 A–D , 42 )

Aenictus rixator var. congolensis SANTSCHI, 1911: 207 (w.)

Syntype, GABON: Mayomba . (1w) [ CASENT0911420 ] NHMB [Examined] ; Syntype, CAMEROON, Grand Batanga (1w) [ CASENT0911445 ] NHMB [Examined].

Aenictus congolensis Santschi ; SANTSCHI, 1917: 277 (q.) [Raised to species]

Syntype Queen, GABON (F. Faure) (1Q, 2w) [ CASENT0911419 ] NHMB [Examined] ; Syntypes same data (18w) NHMB [Examined]; Syntypes same data (17w) MHNG [Examined].

DIAGNOSIS. Identification of A. congolensis is quite straightforward in the rotundatus group due to its developed propodeal ridge and sparse, adpressed white setae and long, digitiform subpetiolar process. The other two species with developed propodeal ridge ( A. nyuyi sp. nov. and A. weissi ) present erect to suberect setae and poorly developed subpetiolar process.

Mesosomal sculpture may be quite variable among individuals, varying from completely and deeply reticulated to individuals with glassy dorsal mesosoma, petiole and postpetiole.

DESCRIPTION ( Fig. 41 A–D ). WORKER. HL: 0.57 [0.51-0.62]; HW: 0.51 [0.46-0.56]; SL: 0.40 [0.35-0.43]; WL: 0.91 [0.79-1.01]; PL: 0.22 [0.19-0.25]; PH: 0.16 [0.15-0.18]; PPL: 0.18 [0.16- 0.20]; PPH: 0.13 [0.12-0.14]; CS: 0.54 [0.48-0.59]; CI: 89 [85-94]; SIL: 70 [67-74]; SIW: 78 [72-85]; WL/HW: 178 [164-191]; PI: 134 [126-143]; PPI: 135 [123-153]; CSR: 122; (n=11).

Scapes relatively long, almost reaching three quarters of head (SIL~70). Funicular segments 1- 2 slightly longer than wide, 3–8 subquadrate, apical about twice longer than wide. Head rectangular, longer than wide (CI~90), convex laterally and widest at the middle. Occipital line straight to slightly concave. Ventrolateral margin present, weak, continuing to one third of its length. Mandibles long, with a sharp apical tooth, a preapical tooth and 5-10 smaller denticles. Clypeus a row of 10–12 conical teeth, clearly visible and longer than wide, the two central between the antennal sockets smaller. Frontal ridges present, not projecting frontally, fused between the antennal sockets and diverging apically.

Pronotum and mesonotum weakly convex, propodeum flat, mesopropodeal suture weak. Transverse mesopleural groove not present. Mesometapleural suture present but very weak; propodeal ridge developed and projecting as a horizontal shelf in dorsal view; propodeal declivity concave.

Petiole subsessile with anterolateral and anterodorsal ridges present, dorsolateral ridge absent. Petiole with an anterior slope a quarter of ellipse, dorsal slope flat and vertical posteriorly, posterodorsal angle straight, not rounded. Postpetiole rounded, with a vertical posterior face, without carinae or ridges of any kind. Subpetiolar process developed with a bulky ellipsoidal process longer than high, followed by a subrectangular rounded lamella oriented 45 degrees forward.

Head, legs and gaster glassy smooth; mandibles finely horizontally rugulose, scapes and funiculus punctuated, shagreened; mesosoma variable, from completely reticulated (including pronotum) to individuals with pronotum, dorsum of mesonotum, petiole and postpetiole smooth; mesopleurae, propodeum and lateral sides of petiole and postpetiole always reticulated. Overall colour brown to dark brown, sometimes slightly lighter at gaster and legs.

Short, adpressed white setae, oriented backwards, present at head, dorsum of pronotum petiole, postpetiole and gaster. No pubescence noted.

OTHER MATERIAL EXAMINED. CENTRAL AFRICAN REPUBLIC: • Res. Dzanga-Shanga, 12,7 km 326º NW Bayanga 370m, 3, 16.2 10-15/05/2001. sifted litter (B.L. Fisher). rainforest (1w), leaf mold, rotten wood [ CASENT0400001 ] CASC • Gabon, Samkito (F. Faure) (3w) [ MRACFOR000001 ] MRAC. REPUBLIC OF CONGO: • Congo, 1923 (A. Théry) (1w) [ EY19929 ] MNHN. GABON: • Samkito (F. Faure) (3w) [ MRACFOR000001 ] MRAC. ZAMBIA: • Central, Lusaka , Leopard Hill , Kapuka Farm 1300 m, -12.55483, 30.29567 30/11/2005 (B.L. Fisher et al.). miombo woodland (1w), ex soil [ CASENT0066799 ] CASC.

DISTRIBUTION. Central Africa and Congo Basin, from Cameroon to Zambia ( Fig. 42 ).

Figures

Fig. 41. Aenictus congolensis, worker (CASENT0066799). A, head, dorsal view. B, habitus, lateral view. C, mesosoma, petiole and postpetiole, lateral view. D, mesosoma, petiole and postpetiole, dorsal view.

Fig. 42. Distribution of A. congolensis.