Aenictus subterraneus

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

Known only from the type locality in a lowland primary forest.

Identification

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

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Malaysia (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 subterraneus. 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.

  • subterraneus. Aenictus subterraneus Jaitrong & Hashimoto, 2012: 40, figs. 6A-E, 7 (w.) BORNEO.

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 2.10 mm; HL 0.55 mm; HW 0.48 mm; SL 0.38 mm; ML 0.78 mm; PL 0.18–0 mm; CI 86; SI 79. Paratypes (n = 2): TL 2.10–2.15 mm; HL 0.55–0.58 mm; HW 0.48–0.50 mm; SL 0.38 mm; ML 0.78–0.80 mm; PL 0.18–0.19 mm; CI 86–87; SI 75–79.

Holotype and paratypes - Head in full-face view clearly longer than broad, with sides convex and posterior margin almost straight or feebly concave; occipital margin bearing a carina. Antennal scape reaching midlength of head; antennal segments II–X each longer than broad; II almost as long as each of III–VI; terminal segment clearly longer than broad and almost as long as VII+VIII+IX. Frontal carina short, slightly 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, 7–8 denticles, and a medium-sized basal tooth; basal margin with 4–5 denticles. Promesonotum in profile convex dorsally and sloping gradually to metanotal groove; metanotal groove distinct; metapleural gland bulla relatively small; distance between propodeal spiracle and metapleural gland bulla clearly longer than spiracular diameter (Fig. 6D). Propodeum in profile lower than promesonotum with weakly convex dorsal outline; propodeal junction obtusely angulate; declivity of propodeum shallowly concave, with lateral carinae, but not demarcated basally by a transverse carina. Petiole shorter than high, with petiole in profile its dorsal outline convex; subpetiolar process rather developed, with a sharply pointed lamellate appendage directed downward. Postpetiole clearly shorter than petiole, its dorsal outline slightly elevated posteriorly.

Head including mandible and antennal scape smooth and shiny; basal portion of the scape finely sculptured. Entire pronotum smooth and shiny except for its anteriormost portion punctate; mesothorax, metapleuron, and propodium entirely microreticulate; petiole and postpetiole entirely punctate except dorsal faces smooth and shiny. Legs entirely smooth and shiny.

Head and mesosoma dorsally with relatively sparse standing hairs mixed with sparse short hairs over the surface; longest pronotal hair 0.15–0.18 mm long. Body yellowish-brown, mandible darker than elsewhere; typhlatta spot absent.

Type Material

  • Holotype, worker, Maliau Basin, Sabah, Borneo, Malaysia, 8 May 2001, Y. Hashimoto, Universiti Malaysia Sabah, Sabah, Malaysia.
  • Paratype, 5 workers, Maliau Basin, Sabah, Borneo, Malaysia, 8 May 2001, Y. Hashimoto, Museum of Nature and Human Activities, Hyogo, Japan; Sk. Yamane Collection at Kagoshima University, Japan; Natural History Museum of the National Science Museum, Thailand.

Etymology

The specific name refers to the behaviour of this species that was collected from soil.

References