Pristomyrmex longus

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Pristomyrmex longus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Pristomyrmex
Species: P. longus
Binomial name
Pristomyrmex longus
Wang, M., 2003

Pristomyrmex longus casent0901728 p 1 high.jpg

Pristomyrmex longus casent0901728 d 1 high.jpg

Specimen Labels

This species has been collected in lowland rainforest.

Identification

Wang (2003) - Worker. Masticatory margin of mandible lacking a diastema and possessing four teeth, of which the third tooth, counting from the apex, smallest; eyes small, with only two to three ommatidia in the longest row; dorsum of petiole node in dorsal view long-oval and longer than broad; first gastral tergite with numerous hairs.

The workers of P. longus are quickly recognizable by the following: In the levigatus group, only three species, [Pristomyrmex boltoni, Pristomyrmex coggii, and Pristomyrmex longus, possess small eyes. Only two species, P. longus and P. obesus, have numerous hairs evenly distributed on the entire first gastral tergite. But in only one species (P. longus ) is the dorsum of the petiole node in dorsal view long-oval and longer than broad; in the other members of the levigatus group, the dorsum of petiole node is subrounded or transverse-oval (i.e., about as long as broad or broader than long).

A member of the Levigatus species group

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: New Guinea (type locality).

Check distribution from AntMaps.

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Pristomyrmex longus for further details

Biology

The biology of most Pristomyrmex species is poorly known. From Wang (2003): Most species of Pristomyrmex dwell in the rainforest, foraging as predators or scavengers. An Asian species, Pristomyrmex punctatus, however, occurs in open and disturbed habitats (e.g., bare hills, agricultural areas, and beaches). These ants prefer to nest in soil, litter, or rotten wood; in rotten parts of living trees; in dead standing trees; or around plant roots.

Pristomyrmex is of great interest because it exhibits several unusual biological and evolutionary phenomena. The absence of morphologically normal queens and reproduction primarily by unmated workers in P. punctatus {=P. pungens) is a highly unusual life history in the Formicidae. Ergatoid queens, a special wingless female caste morphologically intermediate between the queen and the worker, are present in at least four species: Pristomyrmex punctatus, Pristomyrmex africanus, Pristomyrmex wheeleri, and Pristomyrmex mandibularis; two of them (P. africanus and P. wheeleri) possess both queen and ergatoid queen castes.

Simulating death, slowness of movement, and nocturnal foraging has been recorded in Pristomyrmex (Donisthorpe, 1946; Taylor, 1965; Weber, 1941). Colony size varies greatly among species, ranging from about a dozen to several thousand workers (Donisthorpe, 1946; Itow et al, 1984; Mann, 1919; Taylor, 1965, 1968).

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.

  • longus. Pristomyrmex longus Wang, M. 2003: 502, figs. 219-220 (w.q.) NEW GUINEA.

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 2.51, HL 0.67, HW 0.66, CI 99, SL 0.55, SI 83, EL 0.07, PW 0.44, AL 0.66. Workers. TL 2.22-2.68, HL 0.63- 0.70, HW 0.62-0.70, CI 95-100, SL 0.52-0.56, SI 80-87, EL 0.05-0.10, PW 0.40-0.46, AL 0.60-0.70, PPW 0.17-0.18, PPL 0.16-0.16, PPI 104-113 (n = 15).

Mandibles usually smooth and shining. A broad-based short tooth present about midway on the basal margin of the mandible. Clypeus flat, its anterior margin with a median tooth and two lateral teeth; sometimes the median tooth is weak. Frontal area concave, with a median carina that usually extends to the clypeus. Ventral surface of clypeus smooth, lacking any rugae or prominences. Palp formula 1,3. Frontal carinae distinct, extending to the level of the posterior margins of eyes. Scrobal impressions shallow, smooth, present lateral to the frontal carinae. Frontal lobes weakly expanded. Antennal scapes, when lying on the head, dose to the occipital margin. Eyes very small, consisting of 4 to 10 ommatidia, with only two to three ommatidia in the longest row. Occipital margin straight or feebly concave in full-face view. Pronotum unarmed. Propodeum with a pair of triangular teeth. Metapleural lobes rounded. Petiole node in profile high with the anterodorsal angle higher than the posterodorsal, its anterior face subparallel to the posterior one; anterior peduncle of the node about as long as or slightly shorter than the node; subpetiole with a narrow semitranslucent lamella. In dorsal view, dorsum of petiole node long-oval and distinctly longer than broad. Postpetiole in profile rounded dorsally, in dorsal view slightly broader than long or about as long as broad. Dorsum of head between the frontal carinae mostly smooth but usually with some sparse, small, and shallow punctures. Some foveolate punctures present on the genae and around the occipital corners of head. Dorsum of alitrunk, petiole, postpetiole, and gaster usually unsculptured, smooth, and shining. Dorsal surfaces of head, alitrunk, and gaster with numerous erect to suberect hairs. Two pairs of hairs usually present on the dorsal surfaces of petiole node and postpetiole, respectively. A few pairs of forward-projecting hairs present near the anterior clypeal margin. Scapes and tibiae with numerous erect to suberect short hairs. Color yellow-brown to reddish-brown.

Type Material

Holotype Worker. Museum of Comparative Zoology. New Guinea: Huon Pen., Lowe r Busu R., lowl. rainfor., 5.v.1955, #957 (E. O. Wilson). Paratypes.14 workers (MCZC, Australian National Insect Collection, The Natural History Museum). Eight workers with same data as holotype; one worker, New Guinea: Huon Pen., Lower Bush R., lowland rainforest, 6.v.1955, #978 (E. O. Wilson); five workers, New Guinea: 13 km NW Lae, Bubia, lowland rainforest, 26.iii.1955, #688 (E. O. Wilson).

References

  • Wang, M. 2003. A Monographic Revision of the Ant Genus Pristomyrmex (Hymenoptera:Formicidae). Bull. Mus. Comp. Zool. 157(6): 383-542 (page 502, figs. 219-220 worker described)