Aenictus rotundatus

Aenictus rotundatus
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Dorylinae
Genus:	Aenictus
Species group:	rotundatus
Species complex:	rotundatus
Species:	A. rotundatus
Binomial name
	Aenictus rotundatus; Mayr, 1901 Specimen Labels
Synonyms
	Aenictus furibundus Arnold, 1959; Aenictus rotundatus merwei Santschi, 1932;

Specimen records show this species has been collected from Acacia xanthophloea woodland, a Citrus orchard and in a pitfall trap placed in farmland near the edge of a forest.

Identification

Gómez (2022) - A member of the rotundatus species complex in the Aenictus rotundatus species group. 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.

Keys including this Species

Key to the Afrotropical Aenictus

Distribution

Latitudinal Distribution Pattern

Latitudinal Range: 14° to -34.76667°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps; Gomez, 2022

Distribution based on Regional Taxon Lists

Afrotropical Region: Kenya, Lesotho, Namibia, South Africa (type locality), Sudan, Zimbabwe (type locality).

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Castes

Known from the worker caste. Table of castes known for all Afrotropical Aenictus species.

Worker

Gómez 2022. Figure 56A-D. Minor worker, syntype.
Gómez 2022. Figure 57A-D. Major worker.

Images from AntWeb


Worker. Specimen code casent0235823. Photographer Ryan Perry, uploaded by California Academy of Sciences.	Owned by AFRC, Pretoria, South Africa.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

rotundatus. Aenictus rotundatus Mayr, 1901b: 1 (w.) SOUTH AFRICA.
- Type-material: syntype workers (number not stated).
- [Notes (i): Baroni Urbani, 1977e: 67, cites 2w syntypes NHMB; (ii) Gómez, 2022: 73, cites 3w syntypes (2 MHNG, 1 NHMW).]
- Type-locality: South Africa: Cape Colony, Port Elizabeth (H. Brauns).
- Type-depositories: MHNG, NHMB, NHMW.
- Status as species: Emery, 1910b: 31; Forel, 1913a: 112; Arnold, 1915: 138 (redescription); Wheeler, W.M. 1922a: 754; Bolton, 1995b: 60; Gómez, 2022: 73 (redescription).
- Senior synonym of furibundus: Gómez, 2022: 73.
- Senior synonym of merwei: Gómez, 2022: 73.
- Distribution: Kenya, Namibia, South Africa, Sudan, Tanzania, 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”).
- [Note: Gómez, 2022: 73, cites 6w syntypes BMNH.]
- Type-locality: Zimbabwe (“Southern Rhodesia”): Cashel, 16.xi.1916 (G. Arnold).
- Type-depositories: BMNH, SAMC.
- Status as species: Bolton, 1995b: 59.
- Junior synonym of rotundatus: Gómez, 2022: 73.
merwei. Aenictus rotundatus var. merwei Santschi, 1932a: 382 (w.) SOUTH AFRICA.
- Type-material: syntype workers (number not stated).
- [Note: Baroni Urbani, 1977e: 67, cites 6w syntypes NHMB.]
- Type-locality: South Africa: Cape Prov., Montagu, i.1920 (van der Merwe).
- Type-depositories: BMNH, NHMB.
- Subspecies of rotundatus: Weber, 1943c: 293; Bolton, 1995b: 60.
- Junior synonym of rotundatus: Gómez, 2022: 73.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

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.

Description

Worker

Gómez (2022) - HL: 0.60 [0.45-0.77]; HW: 0.51 [0.37-0.71]; SL: 0.39 [0.26-0.51]; WL: 0.92 [0.69-1.19]; PL: 0.21 [0.15-0.26]; PH: 0.17 [0.12-0.22]; PPL: 0.17 [0.12-0.22]; PPH: 0.16 [0.10-0.25]; CS: 0.56 [0.41-0.74]; CI: 85 [80-92]; SIL: 65 [59-70]; SIW: 76 [69-81]; WL/HW: 178 [164-191]; PI: 121 [109-133]; PPI: 110 [87-128]; CSR: 179; (n=44).

With the characteristics of the rotundatus species complex and: Scapes relatively long, almost reaching three quarters of the head (SL/HL~70). Funicular segment 2 slightly longer than wide, the rest subquadrate, the apical about twice longer than wide. Head rectangular, longer than wide (CI~90), convex laterally and widest at the middle. Occipital line straight. Ventrolateral margin present, continuing behind the head to one third of its length. Mandibles triangular with a long, sharp apical tooth followed by 5–6 denticles.

Clypeus a row of 10–14 conical teeth, clearly visible and longer than wide, decreasing to the sides, sometimes eroded. Frontal ridges present, not projecting frontally and fused between the antennal sockets.

Pronotum convex, mesopropodeal suture weak, concave and meeting the propodeum at an angle, this with a very reduced but discernible anterior slope and elevated. Transverse mesopleural groove not present. Mesometapleural suture present but very weak; propodeal ridge present but incomplete as a weak line even in the most sculptured specimens, incomplete and weak especially in minor workers, where it can be absent, never as a ridge; propodeal declivity concave below that line.

Petiole sessile with anterolateral and anterodorsal ridges present, dorsolateral ridge present in the most sculptured workers as a thin line to the propodeal spiracle. Petiole with an anterior slope shaped as a quarter of ellipse, dorsal slope flat and almost vertical posteriorly.

Postpetiole subrectangular with rounded angles and vertical anterior and posteriorly, without carinae or ridges of any kind. Subpetiolar process developed with a bulky paralepidepical to ellipsoidal process, followed by a lamellae variable in size from almost non-existent to about the size of the bulky process very short anteriorly and longer posteriorly, convex at the bottom (shark-fin shaped), usually longer posteriorly than anteriorly.

Variable. Types of A. furibundus and A. rotundatus are as follows: head, pronotum and gaster smooth and shining; mandibles finely horizontally rugulose, scapes and funiculus punctuated, shagreened; mesonotum, propodeum, petiole and postpetiole strongly reticulated, matt.

Overall colour dark brown, slightly lighter at gaster and apex of funiculus.

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].

References

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.