Aenictus glabrinotum

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Aenictus glabrinotum
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Dorylinae
Genus: Aenictus
Species: A. glabrinotum
Binomial name
Aenictus glabrinotum
Jaitrong & Yamane, 2011

Aenictus-glabrinotum-lateral-am-lg.jpg

Aenictus-glabrinotum-dorsal-am-lg.jpg

Paratype Specimen Label

The type series and non-type material examined were collected from lowland rainforests.

Identification

Jaitrong and Yamane (2011) - A. glabrinotum is a distinct species of the A. currax group in having very few standing hairs on the head and promesonotum.

Keys including this Species

Distribution

Borneo (Sabah, Sarawak, and E. Kalimantan).

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo, Indonesia, 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 glabrinotum. 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.

  • glabrinotum. Aenictus glabrinotum Jaitrong & Yamane, 2011: 16, figs. 5-7 (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 and paratype workers (n = 6): TL 3.10–4.05 mm; HL 0.75–0.90 mm; HW 0.62–0.83 mm; SL 0.43–0.70 mm; ML 1.00–1.37 mm; PL 0.28–0.33 mm; CI 83–94; SI 68–85.

(holotype and paratypes). Head in full-face view slightly longer than broad, with sides slightly convex and posterior margin concave; occipital carina complete, not interrupted medially. Antennal scape relatively short, extending slightly beyond midlength of head; antennal segments II–X each longer than broad; II almost as long as each of III–VI. Frontal carina very short, not extending beyond the level of posterior margin of torulus. Parafrontal ridge absent. Anterior margin of clypeus lacking denticles; median portion of clypeal margin almost straight or feebly concave. Masticatory margin of mandible with a large apical tooth followed by a small subapical tooth and 3–4 denticles, which are only slightly smaller than subapical teeth; basal margin bearing 3–4 denticles. Promesonotum in profile weakly convex dorsally and sloping to metanotal groove. Propodeum in profile with almost straight or feebly convex dorsal outline; propodeal junction rounded; declivity of propodeum shallowly concave, and encircled with a thin rim; area below propodeal spiracle distinctly impressed; opening of propodeal spiracle clearly circular with its diameter about 1.6 times as long as diameter of postpetiolar spiracle. Petiole clearly longer than high, with its dorsal outline convex; subpetiolar process relatively low, with its ventral outline straight or weakly convex, and anteroventral corner bluntly produced or roundly angled. Postpetiole almost as long as petiole and clearly longer than high.

Head entirely smooth and shiny; mandible extensively smooth, without fine striation; antennal scape dorsally smooth and ventrally superficially sculptured. Pronotum smooth and shiny except the anterior portion punctate; mesonotum smooth and shiny; mesopleuron finely and densely punctate; metapleuron and lateral face of propodeum with fine rugulae and very minute sculpture but partly smooth; dorsum of propodeum smooth and shiny. Petiole with dorsal surface smooth and shiny, and anterior and lateral faces finely punctate. Postpetiole entirely smooth and shiny. Legs smooth and shiny.

Head with one or two long hairs on vertex (often completely hairless); ventral surface of head also with few (often no) standing hairs. Dorsum of mesosoma usually without standing hairs. Petiole and postpetiole each with only a pair of standing hairs. Hairs on hind femur very short, never overlapping each other; mid and hind tibiae with short appressed hairs only. Entire body dark reddish-brown, with a relatively large typhlatta spot on occipital corner; anterior border of the spot diluted into ground color.

Type Material

Holotype. Worker from Borneo, Sabah, Danum Valley, 29 IV 2000, C. Brühl leg. CB-00-05 (UMS). Five paratype workers, same data as holotype (SKY Collection, Natural History Museum of the National Science Museum).

Etymology

The specific name is a noun meaning the (promeso)notum without standing hairs.

References

  • Jaitrong, W. & Yamane, S. 2011. Synopsis of Aenictus species groups and revision of the A. currax and A. laeviceps groups in the eastern Oriental, Indo-Australian, and Australasian regions (Hymenoptera: Formicidae: Aenictinae). Zootaxa, 3128, 1–46. PDF