Aenictus minimus

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Aenictus minimus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Aenictus
Species group: minutulus
Species: A. minimus
Binomial name
Aenictus minimus
Jaitrong & Hashimoto, 2012

Aenictus-minimus-lateral-am-lg.jpg

Aenictus-minimus-dorsal-am-lg.jpg

Paratype Specimen Label

Aenictus minimus is known only from the type locality. The type series was collected from a disturbed forest in the daytime.

Identification

A member of the minutulus species group. Aenictus minimus is most similar in general appearance to Aenictus changmaianus and Aenictus minutulus (see Aenictus changmaianus for details).

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Oriental Region: Vietnam (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Little is known about the biology of Aenictus minimus. The genus is comprised of species that live an army ant lifestyle. Aenictus typically prey on other ants, from other genera, or other insects such as wasps or termites. There are reports of Aenictus preying on other insects as well and even have been observed collecting honeydew from homopterans (Santschi, 1933; Gotwald, 1995) but this appears, at least from available evidence, to be uncommon. Foraging raids can occur day or night across the ground surface. Occasionally raids are arboreal. During a raid numerous workers attack a single nest or small area, with several workers coordinating their efforts to carry large prey items back to the nest or bivouac. Aenictus have a nomadic life style, alternating between a migratory phase in which nests are temporary bivouacs in sheltered places above the ground and a stationary phase where semi-permanent underground nests are formed. During the nomadic phase bivouacs move regularly, sometimes more than once a day when larvae require large amounts of food. Individual nests usually contain up to several thousand workers, although nest fragments containing only a few hundred workers are often encountered. Queens are highly specialised and look less like workers than in most ant species. They have greatly enlarged gasters (dichthadiform) and remain flightless throughout their life. New colonies are formed by the division of existing colonies (fission) rather than by individual queens starting colonies on their own.

Castes

Known only from the worker caste.

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • minimus. Aenictus minimus Jaitrong & Hashimoto, 2012: 34, figs. 3A-E, 7 (w.) VIETNAM.

Type Material

  • Holotype, worker, My Yen Comm. Forest, Na Hau Village, Thai Nguyen, Vietnam, 9 November 2001, Sk. Yamane, VN01-SKY-29, Vietnam National Museum of Nature.
  • Paratype, 4 workers, My Yen Comm. Forest, Na Hau Village, Thai Nguyen, Vietnam, 9 November 2001, Sk. Yamane, VN01-SKY-29, Sk. Yamane Collection at Kagoshima University, Japan and Natural History Museum of the National Science Museum, Thailand.

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

Description

Worker

Measurements. Holotype: TL 2.15 mm; HL 0.50 mm; HW 0.44 mm; SL 0.28 mm; ML 0.66 mm; PL 0.15 mm; CI 88; SI 63. Paratypes (n = 4): TL 1.80–2.15 mm; HL 0.45–0.50 mm; HW 0.35–0.44 mm; SL 0.23–0.28 mm; ML 0.55–0.66 mm; PL 0.14–0.15 mm; CI 78–88; SI 63–64.

Holotype and paratypes - Head in full-face view subrectangular, clearly longer than broad, with feebly convex sides and shallowly concave posterior margin. Antennal scape reaching midlength of head in larger workers (not reaching midlength of head in smaller workers); antennal segment II longer than broad and almost as long as III+IV; III–VIII each broader than long; terminal segment distinctly longer than broad, 2.1 times as long as broad and longer than VII+VIII+IX. Frontal carina very short, not extending beyond the level of posterior margin of torulus. Masticatory margin of mandible with a large apical tooth followed by a medium-sized subapical tooth, 3–4 denticles, and a medium-sized basal tooth; basal margin with 1–2 small denticles next to basal tooth and followed by a larger denticle. Mesosoma in profile almost flat dorsally; metanotal groove indistinct or almost absent; metapleural gland bulla relatively large and transparent; distance between propodeal spiracle and metapleural gland bulla shorter than spiracular diameter (Fig. 3D). Propodeum in profile with straight dorsal outline; propodeal junction right-angled in larger workers (roundly convex in smaller workers); declivity of propodeum shallowly concave, with lateral carinae, but not demarcated basally by a transverse carina. Petiole slightly shorter than high, with its dorsal outline convex, slightly elevated posteriorly; subpetiolar process large, rectangular; anterior and posterior corners each acutely angulate. Postpetiole slightly shorter than petiole, its dorsal outline convex.

Head including mandible and antennal scape smooth and shiny; entire mesosoma smooth and shiny except mesopleuron, upper portions of metapleuron, and area between propodeal spiracle and metapleural gland bulla that are superficially reticulate. Petiole and postpetiole entirely smooth and shiny. Legs entirely smooth and shiny. Head and mesosoma dorsally with relatively dense standing hairs mixed with sparse short hairs over the surface; longest pronotal hair 0.07–0.08 mm long. Ground color yellow; typhlatta spot absent.

Etymology

The species epithet “minimus” is a Latin word meaning minimum. This refers to this species being the smallest within this species group.

References

  • Jaitrong, W. & Hashimoto, Y. 2012. Revision of the Aenictus minutulus species group (Hymenoptera Formicidae Aenictinae) from Southeast Asia. Zootaxa 3426, 29-44.