Aenictus rotundatus

Identification
The species as defined here is highly variable in subpetiolar process, colour and sculpture, and maybe candidate for being a cryptic species complex. Series from Kenya and Tanzania are lighter, smoother and most of the individuals do not present lamellae at the subpetiolar process, measurements and indexes fall nonetheless into the typical A. rotundatus series and clustering analysis fails to differentiate both series.

Details for separation of the rest of species in the complex under Aenictus guineensis, its sibling species.

Distribution based on Regional Taxon Lists
Afrotropical Region: Kenya, Lesotho, Namibia, South Africa, Sudan, Zimbabwe.

Castes
Known only from the worker caste.

Nomenclature

 * . Aenictus rotundatus Mayr, 1901b: 1 (w.) SOUTH AFRICA.
 * Type-material: syntype workers (number not stated).
 * Type-locality: South Africa: Cape Colony, Port Elizabeth (H. Brauns).
 * Type-depositories: NHMB, NHMW.
 * Status as species: Emery, 1910b: 31; Forel, 1913a: 112; Arnold, 1915: 138 (redescription); Wheeler, W.M. 1922a: 754; Bolton, 1995b: 60.
 * Distribution: South Africa, Zimbabwe.
 * furibundus. Aenictus furibundus Arnold, 1959: 335, figs. 20, 20a,b (w.) ZIMBABWE.
 * Type-material: syntype workers (number not stated, “a large colony of some thousands of individuals”).
 * Type-locality: Zimbabwe (“Southern Rhodesia”): Cashel (G. Arnold).
 * Type-depositories: BMNH, SAMC.
 * Status as species: Bolton, 1995b: 59.
 * Junior synonym of rotundatus: Gomez, 2022: 73.
 * Distribution: Zimbabwe.
 * merwei. Aenictus rotundatus var. merwei Santschi, 1932a: 382 (w.) SOUTH AFRICA.
 * Type-material: 6 syntype workers.
 * Type-locality: South Africa: Cape Prov., Montagu, i.1920 (v.d. Merwe).
 * Type-depository: NHMB.
 * Subspecies of rotundatus: Weber, 1943c: 293; Bolton, 1995b: 60.
 * Junior synonym of mariae: Gomez, 2022: 73.
 * Distribution: South Africa.

Type Material

 * Aenictus rotundatus
 * Syntype worker, SOUTH AFRICA Cape Town (1W) NHMB [Examined by Gomez, 2022]; Syntype, same data (1w) NHMB [Examined by Gomez, 2022]; Syntype, SOUTH AFRICA: Capeland 1895 (2w) MHNG: Coll. Forel [Examined by Gomez, 2022]; Syntype, SOUTH AFRICA: Eastern Cape, Port Elizabeth (1w) [CASENT0919641] NMHW: Coll. Mayr [Examined by Gomez, 2022].
 * Aenictus rotundatus merwei
 * Syntype worker, SOUTH AFRICA: Montagu C. P. (Western Cape) 1.i.1920 (Merve) NHMB [CASENT0911439] [Material seen on web by Gomez, 2022]; Syntypes, same data (4w) [NHMUK012849252] BMNH [Examined by Gomez, 2022].
 * Aenictus furibundus
 * Syntype workers, ZIMBABWE: Cashel, S. Rhodesia. 16.xi.1916 (Arnold, G.) (6w) [BMNH(E)1015732, CASENT0902688] BMNH [Examined by Gomez, 2022].

Taxonomic Notes
Types of A. furibundus are identical to types of A. rotundatus. Curiously enough, ARNOLD (1959) uses A. eugenii for comparison, and not A. rotundatus. These two series are strongly reticulated and dark brown, except for some individuals with smooth dorsopropodeum, petiole and postpetiole. Types of the A. rotundatus merwei form are yellowish and much smoother, as stated in its description by SANTSCHI (1932). Nonetheless, as sculpture and subpetiolar lamella have a high degree of variation even in the same nest series, I’d rather consider them as a unique species until genetic data are available.

References based on Global Ant Biodiversity Informatics

 * Arnold G. 1915. A monograph of the Formicidae of South Africa. Part I. Ponerinae, Dorylinae. Annals of the South African Museum 14: 1-159.
 * Borowiec M. L. 2016. Generic revision of the ant subfamily Dorylinae (Hymenoptera, Formicidae). ZooKeys 608: 1–280.
 * Botes, A., M.A. McGeoch, H.G. Robertson, A. van Niekerk, H.P. Davids and S.L. Chown. 2006. Ants, altitude and change in the northern Cape Floristic Region. Journal of Biogeography 33:71-90
 * Emery C. 1910. Hymenoptera. Fam. Formicidae. Subfam. Dorylinae. Genera Insectorum 102: 1-34.
 * Hita Garcia, F., G. Fischer, M.K. Peters, R.R. Snelling and H.W. Wagele. 2009. A preliminary checklist of the ants (Hymenoptera: Formicidae) of Kakamega Forest (Kenya). Journal of East African Natural HIstory 98(2): 147-165.
 * IZIKO South Africa Museum Collection
 * Mauda E. V., G. S. Joseph, C. L. Seymour, T. C. Munyai, and S. H. Foord. 2018. Changes in landuse alter ant diversity, assemblage composition and dominant functional groups in African savannas. Biodivers Conserv 27: 947–965.
 * Medler J. T. 1980: Insects of Nigeria - Check list and bibliography. Mem. Amer. Ent. Inst. 30: i-vii, 1-919.
 * Taylor B. 1980. Ants of the Nigerian Forest Zone (Hymenoptera: Formicidae). V. Dorylinae, Leptanillinae. Cocoa Research Institute of Nigeria Research Bulletin 8: 1-33.