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Aenictus bidentatus
| Aenictus bidentatus | |
|---|---|
| |
| Scientific classification (junior synonym of Aenictus decolor) | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Hymenoptera |
| Family: | Formicidae |
| Subfamily: | Dorylinae |
| Genus: | Aenictus |
| Species group: | decolor |
| Species: | A. bidentatus |
| Binomial name | |
| Aenictus bidentatus Donisthorpe, 1942
| |
This species has been collected by hand in mesic forests and from pitfall traps in disturbed areas.
Identification
Gomez (2022) - A member of the Aenictus decolor species group. The three sibling species of the group are almost identical in any morphological aspect except size and relative length of scapes. This fact led Gotwald and Leroux (1980) to propose the synonymy between Aenictus batesi, Aenictus bidentatus and Aenictus decolor, although “the type specimens of A. decolor and batesi are larger than those of bidentatus, but in all other characteristics [...] appear identical” (Gotwald and Leroux, 1980). Aenictus villiersi could also easily be included in the statement except for its poorly developed subpetiolar process.
Morphometrical analysis regarding SL and HL clearly separates the three species. Aenictus bidentatus is consistently smaller (0.54<HL<0.7) and with smaller scapes (63<SIL<76), while A. decolor is larger (0.7<HL<0.76) with much longer scapes (83<SIL<89). These two species present a developed subpetiolar process with lamella, while the third sibling species A. villiersi is similar in size to A. decolor, but with a small subpetiolar process and very long scapes (95<SIL<102).
Keys including this Species
Distribution
Latitudinal Distribution Pattern
Latitudinal Range: 8° to -0.317°.
| North Temperate |
North Subtropical |
Tropical | South Subtropical |
South Temperate |
- Source: AntMaps; Gomez, 2022
Distribution based on Regional Taxon Lists
Afrotropical Region: Cameroun, Ghana, Ivory Coast, Kenya, Nigeria, Uganda.
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. |
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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. |
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Biology
Castes
Only known from the worker caste; Table of known castes for all Afrotropical Aenictus species.
Nomenclature
The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.
- bidentatus. Aenictus (Aenictus) bidentatus Donisthorpe, 1942e: 701 (w.) GHANA.
- Type-material: 7 syntype workers.
- Type-locality: Ghana (“Gold Coast”): E.P., Tafo, ix.1940, No. 1352, ex cocoa (G.S. Cotterell).
- [Note: type-locality incorrectly recorded as New Guinea by Chapman & Capco, 1951: 10.]
- Type-depository: BMNH.
- Junior synonym of decolor: Gotwald & Leroux, 1980: 600; Bolton, 1995b: 59.
- Status as species: Gómez, 2022: 19 (redescription).
- Distribution: Cameroon, Ghana, Ivory Coast, Kenya, Nigeria, Uganda.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Description
Worker
Gomez (2022) - HL: 0.61 [0.51-0.67]; HW: 0.59 [0.48-0.65]; SL: 0.43 [0.38-0.49]; WL: 0.96 [0.80-1.07]; PL: 0.23 [0.19-0.25]; PH: 0.18 [0.15-0.2]; PPL: 0.18 [0.15-0.20]; PPH: 0.16 [0.13-0.18]; CS: 0.60 [0.50-0.65]; CI: 97 [91-103]; SIL: 70 [63-76]; SIW: 72 [64-80]; WL/HW: 162 [145-176]; PI: 122 [115-135]; PPI: 112 [100-128]; CSR: 131; (n=25).
With the characters defined for the decolor species-group and: scape long, surpassing three quarters of the head when laid back (SIL~88). Funicular segments 1–7 subquadrate, preapical longer than wide, apical more than twice longer than wide; the last three slightly widened but not becoming an apical club. Head subquadrate (CI~97), widest at distal third and narrowing to vertex, this a straight line and shorter than the line at mandible insertions.
Petiole subsessile with anterolateral and sometimes anterodorsal carina present, dorsolateral carina absent; propodeal dome rounded, “pushed” backwards, anteriorly sloping at approximately 45 degrees and almost vertical posterior face in lateral view, all angles rounded; sometimes petiole with anterior and dorsal faces straight, angles rounded. Postpetiole subrectangular with almost vertical anterior and vertical posterior faces, the dorsal straight and horizontal, both angles rounded square; the anterior face slightly lower with a more tended rounded angle. Subpetiolar process developed, subrectangular and without lamella, uncommonly a faint ridge or small lamella present.
Head, pronotum (except its anterior declivity), mesonotum gaster, scapes, legs and dorsal surfaces of petiole and postpetiole glassy smooth. Mandibles finely striated; meso and metapleurae strongly and irregularly rugulose especially at the mesopleurae; in some individuals mostly reticulated, but always some horizontal rugulae present at the lateropropodeum; dorsopropodeum finely rugulose; remainder of petiole and posteptiole alutaceus to faintly rugulose; surface between rugulae glossy.
Head and mesosoma reddish brown to dark reddish brown, especially at mandibles and propodeum. Gaster, coxae, legs and distal half of funiculus yellow to yellowish brown.
Whole body with long, sparse, white fine setae; decumbent to adpressed in scape, slightly longer than scape width, semierect in funiculus size about the funiculus width, decumbent setae at legs, size about femora width, erect to semierect in the rest of the body, unequal, the longest about petiole height. No pubescence noted.
Type Material
- Holotype, GHANA: Tafo. ix-1940, ex. cocoa. Nº 1352 (G.S. Cotterell) (1w) [BMNH(E)1015729, CASENT0902685] BMNH [Examined by Gomez, 2022].
- Paratypes, same data (3w each) [NHMUK012849178, NHMUK012849179], BMNH [Examined by Gomez, 2022].
References
- Donisthorpe, H. 1942f. New species of ants (Hym., Formicidae) from the Gold Coast, Borneo, Celebes, New Guinea and New Hebrides. Ann. Mag. Nat. Hist. 11(9): 701-709.(page 701, worker described)
- Bolton, B. 1995b. A new general catalogue of the ants of the world. Cambridge, Mass.: Harvard University Press, 504 pp. (page 59, catalogue)
- Gomez, K. 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: 1–86 (doi:10.5281/zenodo.5898821).
- Gotwald, W. H., Jr.; Leroux, J. M. 1980. Taxonomy of the African army ant, Aenictus decolor (Mayr), with a description of the queen (Hymenoptera: Formicidae). Proc. Entomol. Soc. Wash. 82: 599-608 (page 600, junior synonym of decolor)
- Taylor, B., Agoinon, N., Sinzogan, A., Adandonon, A., Kouaguou, Y. N., Bello, S., Wargui, R., Anato, F., Ouagoussounon, I., Houngbo, H., Tchibozo, S., Todjihounde, R., Vayssieres, J.F. 2018. Records of ants (Hymenoptera: Formicidae) from the Republic of Benin, with particular reference to the mango farm ecosystem. Journal of Insect Biodiversity 8(1): 6-29 (doi:10.12976/jib/2018.08.1.2).