Aenictus paradentatus

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

Aenictus paradentatus casent0903682 p 1 high.jpg

Aenictus paradentatus casent0903682 d 1 high.jpg

Specimen Labels

Aenictus paradentatus occurs from low-lands to highlands (up to 1,300 m a.s.l., Doi Ang Khang, N. Thailand) and inhabits primary and disturbed forests (rarely marching even in grasslands in the mountain range of N. Vietnam). It has been observed preying on other ants such as species of Leptogenys (Vietnam, VN98-SKY-15), Oecophylla (Thailand, HKK10-06-06), Pachycondyla (Laos, WJT10-LAO16) and Pheidole (Vietnam, VN98-SKY-15), and also on termites, Macrotermes sp. (Laos, WJT10-LAO12).

Identification

A member of the pachycerus group. Jaitrong, Yamane and Wattanachai (2012) - Aenictus paradentatus and Aenictus dentatus are very similar in general appearance as they share the distinctive coarse sculpture on head and mesosoma, and the relatively long antennal scape, extending beyond the posterior margin of the head. However, they differ in several significant characters. The antennal scape is relatively shorter in A. paradentatus (SI 117 - 124) than in A. dentatus (SI 143-152). No overlap is observed in HW / SL between the species. The posterior portion of the head in full-face view is relatively broader in A. paradentatus than in A. dentatus. The first gastral tergite is weakly shagreened with smooth interspaces in the former, while it is wholly smooth and shiny in the latter. The petiole has no peduncle in the former, but has a short but distinct peduncle in the latter.

Keys including this Species

Distribution

Vietnam, Laos, and Thailand

Distribution based on Regional Taxon Lists

Oriental Region: Laos, Thailand (type locality), Vietnam.
Palaearctic Region: China.

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 paradentatus. 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.

  • paradentatus. Aenictus paradentatus Jaitrong & Yamane, in Jaitrong, Yamane & Tasen, 2012: 136, figs. 6-12 (w.) THAILAND.

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). Measurements of holotype: TL 4.65 mm; HL 1.03 mm; HW 0.90 mm; SL 1.08 mm; ML 1.53 mm; PL 0.33 mm; CI 88; SI 119. Paratypes (n = 9): TL 4.55 - 4.65 mm; HL 0.95 - 1.05 mm; HW 0.80 - 0.93 mm; SL 0.93 - 1.08 mm; ML 1.50 - 1.55 mm; PL 0.33 - 0.35 mm; CI 83 - 88; SI 117 - 124.

Head in full-face view round, slightly longer than broad, with convex sides and posterior margin; occipital carina bearing distinct collar. Antenna 10-segmented; scape long, extending beyond posterolateral corner of head; funicular segment I almost as long as II, but slightly shorter than III - VI; apical segment almost as long as three previous ones. Frontal carinae well developed, fused at level of antennal base to form a single carina, extending less than half length of head, very poorly developed in posterior half. Parafrontal ridge well developed, extending 1/3 of head length; seen in profile, its anteriormost part well devel-oped and subtriangular. Clypeus short and roundly produced anteriorly, lacking anterior denticles. Mandible triangular, its masticatory margin with large apical tooth, fol-lowed by 11 - 12 denticles; basal margin of mandible lacking denticles. Mesosoma rather elongate and stout; pro-mesonotum in profile with strongly convex dorsum, sloping gradually to metanotal groove; propodeum lower and with almost straight dorsum; mesopleuron not demarcated from metapleuron; propodeal junction acutely angulated, protruding as ridge that is often slightly upward directed; declivity of propodeum shallowly concave, encircled with very narrow rim. Petiole almost as long as high without peduncle, its dorsal outline elevated posteriorly; subpetiolar process generally very low, its ventral outline weakly convex. Postpetiole seen in profile slightly larger than petiole, its dorsal outline elevated posteriorly. Gaster elliptical, narrowed anteriorly and posteriorly.

Head, mesosoma, petiole and postpetiole entirely and densely micropunctate and opaque. In addition, promesonotum dorsally rugose, laterally with approximately ten longitudinal rugae; dorsal petiolar surface with longitudi-nal or irregular rugae. First gastral segment very weakly shagreened with smooth and shiny interspaces, except in basalmost part with dense micropunctures.

Head and mesosoma with relatively dense standing hairs; length of longest pronotal hairs 0.43 - 0.45 mm. Entire body dark reddish brown or dark brown. Typhlatta spot absent.

Type Material

Holotype: worker from Doi Suthep-Pui National Park, Muang Dist., Chiang Mai Prov., N. Thailand, 20. VIII.1998, W. Jaitrong leg., WJT98-PD01 (THNHM). Paratypes: 17 workers, same data as holotype (BMNH, MCZC, MHNG, SKYC, THNHM).

Etymology

The specific epithet paradentatus is a compound word meaning "similar to dentatus". Non-type materials examined.

References

  • Jaitrong, W. & Wiwatwitaya, D. 2013. Two new new species of the Aenictus pachycerus species group (Hymenoptera: Formicidae: Aenictinae) from Southeast Asia. Raffles Bulletin of Zoology 61, 97-102.
  • Jaitrong, W., Yamane, S. & Tasen, W. 2012. A sibling species of Aenictus dentatus FOREL, 1911 (Hymenoptera: Formicidae) from continental Southeast Asia. Myrmecological News 16: 133-138.