Aenictus brevipodus

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Aenictus brevipodus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Aenictus
Species: A. brevipodus
Binomial name
Aenictus brevipodus
Jaitrong & Yamane, 2013

Known only from the type locality in the lowland (450–650m alt.).

Identification

A member of the ceylonicus group. Aenictus brevipodus is similar to Aenictus doryloides as they share the strongly concave anterior clypeal margin and basal margin of mandible. However, A. brevipodus is easily separated from the latter by the following characteristics: promesonotum weakly convex (mesosomal dorsum flat in the latter); metanotal groove distinct and deep (indistinct or almost absent in the latter).

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 brevipodus. 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.

  • brevipodus. Aenictus brevipodus Jaitrong & Yamane, 2013: 176, figs. 3A-C (w.) VIETNAM.

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

Description

Worker

(Holotype and paratypes, n = 3). TL 3.00-2.85 mm; HL 0.60-0.58 mm; HW 0.58-0.50 mm; SL 0.40-0.38 mm; ML 1.00-0.95 mm; PL 0.25 mm; CI 90-96; SI 65-70.

Head in full-face view subrectangular, slightly longer than broad, sides weakly convex and posterior margin feebly convex; with head in profile occipital corner bearing a distinct carina. Antennal scape relatively short, not reaching 1/2 of head length. Frontal carina relatively long, extending beyond the level of posterior margin of torulus. Parafrontal ridge indistinct. Anterior clypeal margin strongly concave, lacking denticles and concealed by curved anterior extension of frontal carina. Masticatory margin of mandible with 4 teeth, including a large apical tooth; basal margin strongly concave. Maximum width of gap between anterior clypeal margin and mandibles 1.8-2.0 times as broad as maximum width of mandible. Promesonotum rather stout, weakly convex dorsally and sloping gradually to metanotal groove; metanotal groove distinct, deep; anepisternum demarcated from katepisternum by a shallow groove; mesopleuron clearly demarcated from metapleuron by a deep groove. Propodeum in profile with weakly convex dorsal outline; propodeal junction angulated, nearly right-angled; declivity of propodeum shallowly concave, and encircled with a distinct rim; metapleural gland bulla relatively large, its maximum diameter about 3.3 times as long as distance between propodeal spiracle and metapleural gland bulla. Petiole almost as long as high, with its dorsal outline convex; subpetiolar process generally very low, subrectangular with its anteroventral and posteroventral corners angulate, and margin between the corners almost straight. Postpetiole rounded, almost as long as petiole. Legs relatively short.

Head and gaster smooth and shiny; basal half of antennal scape densely microreticulate but apical half superficially microreticulate and shiny; mandible finely striate except along masticatory margin smooth and shiny. Pronotum smooth and shiny except for anteriormost portion reticulate; mesothorax densely reticulate; metapleuron reticulate, partly smooth and shiny; propodeum entirely reticulate, its dorsum somewhat shiny. Petiole and postpetiole entirely reticulate except dorsa smooth and shiny. Basal 1/3 of femora finely microreticulate, apical 2/3 smooth and shiny; basal half of tibiae microreticulate (but the reticulation weaker than on basal 1/3 of femora), apical half smooth and shiny.

Head and mesosoma dorsally with relatively dense standing hairs; longest pronotal hair 0.13-0.15 mm long. Body yellowish brown; antenna and mandible dark brown; legs yellowish brown except basal 1/3 of femora dark brown.

Type Material

Holotype. VIETNAM: Worker from N. Vietnam, Lao Cai Prov., Van Ban Dist., Liem Phu (450-650 m alt.), 28.IX.2006, leg. K. Eguchi, Eg28ix06-10 (VNMN). Paratypes. Nine workers, same data as holotype (SKYC, THNHM).

Etymology

The specific name refers to the short legs, especially fore tibiae.

References