Pristomyrmex simplex

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

Pristomyrmex simplex casent0901729 p 1 high.jpg

Pristomyrmex simplex casent0901729 d 1 high.jpg

Specimen Labels

This species occurs in rainforest and has been collected in litter samples.

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; dorsal surfaces of alitrunk and head between the frontal carinae with scattered foveolate punctures; eyes usually containing five (rarely four) ommatidia in the longest row; a few hairs present on the first gastral tergite.

This species occurs in New Guinea. It is closely related to Pristomyrmex levigatus and Pristomyrmex obesus. It is separable from P. levigatus by possessing some foveolate punctures on the dorsum of the alitrunk in the workers and on the dorsal head between the frontal carinae in the workers and queens. It differs from P. obesus because the workers of P. simplex have only a few hairs on the first gastral tergite. Pristomyrmex simplex differs from Pristomyrmex coggii by the following characters: The eyes usually contain five (sometimes four) ommatidia in the longest row in the workers of P. simplex but two to three ommatidia in P. coggii; the dorsum of the head has foveolate-reticulate sculpture in the workers and queens of P. coggii but scattered foveolate punctures in P. simplex.

A member of the Levigatus species group

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: New Guinea, Philippines.

Check distribution from AntMaps.

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Pristomyrmex simplex 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

Males have yet to be collected.

Worker

Nomenclature

The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.

  • simplex. Pristomyrmex simplex Wang, M. 2003: 512, figs. 237-240 (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 2.48, HL 0.66, HW 0.69, CI 105, SL 0.52, SI 75, EL 0.12, PW 0.46, AL 0.58. Workers. TL 2.42-2.64, HL 0.65-0.68, HW 0.66-0.70, CI 100-105, SL 0.52-0.54, SI 74-79, EL 0.09-0.12, PW 0.44-0.46, AL 0.58-0.66, PPW 0.18-0.20, PPL 0.14-0.16, PPI 119-129 (n = 6).

Mandibles usually smooth and shining but sometimes with a few small shallow hair pits and a few superficial short rugae. A broad-based triangular short tooth present about midway on the basal margin of the mandible. Clypeus flat, smooth, and shining, usually unsculptured but sometimes the median carina of the frontal area extending to the clypeus. Anterior clypeal margin with a median denticle and two lateral teeth; the median denticle is often smaller than the others; sometimes the median denticle is absent so that the only two teeth are present there. Ventral surface of clypeus lacking rugae or toothlike prominences. Palp formula 1,3. Frontal carinae distinct, extending to the level of the posterior margins of eyes. Scrobal areas slightly concave, present lateral to the frontal carinae. Frontal lobes weakly expanded. Eyes moderately sized, about 0.14 to 0.17 X HW, usually containing five (sometimes four) ommatidia in the longest row. Occipital margin 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 peduncle about as long as the node. Subpetiole with a narrow rim. Postpetiole in profile rounded dorsally. In dorsal view, dorsum of petiole node transoval and dorsum of postpetiole somewhat transversely rectangular. Dorsum of head between the frontal carinae with scattered foveolate punctures, varying from a few feeble punctures to numerous distinct ones; spaces between foveolae often smooth. Dorsum of alitrunk with a few to some scattered foveolate punctures. Petiole, postpetiole, and gaster smooth and shining. Dorsal surfaces of head and alitrunk with numerous erect to sub erect hairs. Two pairs of hairs usually present on the dorsal surfaces of petiole node and postpetiole, respectively, and a few near the base of the first gastral tergite. A few pairs of forward-projecting hairs present near the anterior clypeal margin. Scapes and tibiae with some erect to suberect short hairs. Color reddish-brown.

Queen

TL 2.51-2.84, HL 0.66-0.70, HW 0.66-0.71, CI 100-101, SL 0.51-0.58, SI 76-82, EL 0.14-0.16, PW 0.50-0.55, AL 0.66-0.81, PPW 0.19-0.21, PPL 0.15-0.18, PPI 114-13.3 (n= 3).

Generally similar to worker, except for caste differences. In addition, mesoscutum rather smooth and shining, but mesoscutellum with a few foveolate punctures; propodeal armaments slightly shorter than those in the conspecific worker.

Type Material

Holotype.. Australian National Insect Collection. Papua: 8 km S of Kokoda, 800 m, rainforest, ANIC Berleasate, No. 382, l.vi.1972 (R. W. Taylor). Paratypes, six workers and three queens (Museum of Comparative Zoology, ANIC, The Natural History Museum ). One worker with same data as holotype; two workers, Papua: Karema, Brown R., lowl. rainfor., 8-11.iii.1955 (E. O. Wilson); three workers and one queen, Papua New Guinea: Port Moresby, Brown River, 2.x.1969 (J. Balogh); one queen, Papua: N. Dist., 27.xii.1971 (P. M. Room); one queen, Papua: N. Dist., Debelou, 23.vi.197:3 (P. M. Room).

References

  • Wang, M. 2003. A Monographic Revision of the Ant Genus Pristomyrmex (Hymenoptera:Formicidae). Bull. Mus. Comp. Zool. 157(6): 383-542 (page 512, figs. 237-240 worker, queen described)