Aenictus bidentatus

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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

Aenictus decolor casent0281966 p 1 high.jpg

Aenictus decolor casent0281966 d 1 high.jpg

Specimen Labels

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

Distribution based on Regional Taxon Lists

Afrotropical Region: Cameroun, Ghana, Ivory Coast, Kenya, Nigeria, Uganda.

Distribution based on AntMaps

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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 bidentatus Donisthorpe, 1942e: 701 (w.) GHANA.
    • Junior synonym of decolor: Gotwald & Leroux, 1980: 600.
    • Status as species: Gomez, 2022: 19.

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

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