Aenictus longinodus

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

The type series, two colonies from Ton Nga Chang Wildlife Sanctuary, and a colony from Khao Luang National Park were collected in lowland rainforests. A colony was collected from an open area in the day, while a colony, just coming out of soil, was from a disturbed forest near a concrete road in the night. Thus, this species inhabits both primary and disturbed forests and is active in the day and night. (Jaitrong & Yamane 2012)

Identification

A member of the javanus species group. This species is most similar to Aenictus javanus (see A. javanus for details).

Keys including this Species

Key to Aenictus javanus group species

Distribution

Malay Peninsula (S. Thailand)

Latitudinal Distribution Pattern

Latitudinal Range: 15.145662° to 15.145662°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Oriental Region: Thailand (type locality).

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Explore Overview of Aenictus biology

Little is known about the biology of Aenictus longinodus. 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.

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Castes

Known only from the worker caste.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

longinodus. Aenictus longinodus Jaitrong & Yamane, 2012: 59, figs. 4, 7B (w.) THAILAND.
- Type-material: holotype worker, 37 paratype workers.
- Type-locality: holotype Thailand: Trang Prov., Khao Chong Botanical Garden, 8.xi.2003, THNHM-103-942 (= TH03-WJT-713), dry evergreen forest (W. Jaitrong); paratypes with same data.
- Type-depositories: TNHM (holotype); BMNH, MCZC, MHNG, SKYC, TNHM (paratypes).
- Status as species: Khachonpisitsak, et al. 2020: 29.
- Distribution: 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: TL 2.55 mm; HL 0.55 mm; HW 0.53 mm; SL 0.33 mm; ML 0.80 mm; PL 0.25 mm; CI 95; SI 62.

Larger workers (paratypes, n = 8): TL 2.45-2.60 mm; HL 0.55-0.58 mm; HW 0.53- 0.55 mm; SL 0.33-0.35 mm; ML 0.80-0.88 mm; PL 0.25 mm; CI 95-96; SI 61-64. Smaller workers (paratypes, n = 4): TL 1.90-2.00 mm; HL 0.45-0.53 mm; HW 0.40-0.43 mm; SL 0.22-0.28 mm; ML 0.63-0.73 mm; PL 0.18-0.19 mm; CI 85-89; SI 56-61.

Head in full-face view slightly longer than broad, with sides convex and posterior margin almost straight; seen in profile occipital corner of head rounded. Antennal scape reaching midlength of head; antennal segment II longer and narrower than each of III-VI; terminal segment about 2 times as long as broad. Anterior margin of clypeus bearing 7 denticles. Masticatory margin of mandible with 3 acute teeth including a large apical tooth; basal margin lacking denticles. Promesonotum seen in profile almost flat or weakly convex dorsally and sloping gradually to propodeal junction; in profile propodeum slightly lower than promesonotum and almost flat dorsally; propodeal junction angulate, right-angled; declivity of propodeum shallowly concave, encircled by a thin rim. Petiole longer than high, its dorsal outline convex; subpetiolar process well developed, subrectangular, its ventral margin almost straight or weakly convex and slightly longer than posterior margin; postpetiole seen in profile subrectangular and slightly shorter than petiole.

Head including antennal scape smooth and shiny; mandible striate along basal margin and smooth in apical and peripheral parts. Dorsal and lateral surface of pronotum smooth and shiny except for anteriormost part microreticulate; mesothorax, metapleuron and propodeum microreticulate. Petiole entirely microreticulate. Postpetiole microreticulate except for a small smooth and shiny area on dorsal surface.

Head and mesosoma dorsally with relatively sparse standing hairs mixed with sparse short hairs over the surface; longest pronotal hairs 0.13-0.15 mm long. Head, mesosoma, petiole and postpetiole reddish brown; gaster yellowish brown and paler than the other parts of body; propodeum darkest.

Type Material

Holotype worker from S. Thailand, Trang Prov., Khao Chong Botanical Garden, evergreen forest, 8.XI.2003, W. Jaitrong, THNHM-I03–942 (= TH03-WJT-713, Natural History Museum of the National Science Museum). Thirty-seven paratype workers, same data as holotype (The Natural History Museum, Museum of Comparative Zoology, Musee d'Histoire Naturelle Genève, SKY Collection, Natural History Museum of the National Science Museum).

Etymology

The specific name refers to the long petiole.

References

Jaitrong, W. & Yamane, S. (2012) Review of the Southeast Asian species of the Aenictus javanus and Aenictus philippinensis species groups (Hymenoptera, Formicidae, Aenictinae). ZooKeys 193: 49–78, doi: 10.3897/zookeys.193.2768.
Khachonpisitsak, S., Yamane, S., Sriwichai, P., Jaitrong, W. 2020. An updated checklist of the ants of Thailand (Hymenoptera, Formicidae). ZooKeys 998, 1–182 (doi:10.3897/zookeys.998.54902).

References based on Global Ant Biodiversity Informatics

Borowiec M. L. 2016. Generic revision of the ant subfamily Dorylinae (Hymenoptera, Formicidae). ZooKeys 608: 1–280.
Jaitrong W. 2015. A revision of the Thai species of the ant genus Aenictus Shuckard, 1840 (Hymenoptera: Formicidae: Dorylinae). The Thailand Natural History Museum Journal 9(1): 1-94.
Jaitrong W., and S. Yamane. 2012. Review of the Southeast Asian species of the Aenictus javanus and Aenictus philippinensis species groups (Hymenoptera, Formicidae, Aenictinae). ZooKeys 193: 49-78.