Pristomyrmex collinus

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

Pristomyrmex collinus casent0901723 p 1 high.jpg

Pristomyrmex collinus casent0901723 d 1 high.jpg

Specimen Labels

This species hs been collected in forest habitat.

Identification

Wang (2003) – Worker. Pronotum and propodeum each with a pair of short spines; dorsal surfaces of head and alitrunk unsculptured, smooth, and highly polished; petiole node with one to two pairs of hairs, and with the anterior face of the node distinct from the upper surface of peduncle; HW 0.77-0.94 and HL 0.82-0.94.

This species is known only from the Philippines with two closely related species co-occuring with it in Southeast Asia: Pristomyrmex flatus, also from the Philippines, and Pristomyrmex quadridens, from New Guinea, Indonesia, and Pohnpei. Of its more distant five relatives, two, Pristomyrmex africanus and Pristomyrmex trogor occur in Africa; and the other three, Pristomyrmex quadridentatus, Pristomyrmex wheeleri, and Pristomyrmex erythropygus, are endemic to Australia.

The following characters can be used to separate the workers of P. collinus from those of P. flatus: P. collinus - Promesonotum in dorsal view showing a convex dorsum. Anterior face of petiole node, in profile, distinct from the upper surface of its anterior peduncle. Smaller species, with HW 0.77-0.94, HL 0.82-0.94, EL 0.14-0.18. P. flatus - Promesonotum in dorsal view depressed or shallow-concave. Anterior face of petiole node not distinct from the upper surface of the peduncle. Larger species, with H\V 0.98-1.04, HL 0.94-1.02, EL 0.22-0.24. A list of characters separating P. collinus and P. flatus from P. quadridens and from two African and from three Australian species is provided under P. flatus.

A member of the Quadridens species group

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Philippines (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

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

Worker

Nomenclature

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

  • collinus. Pristomyrmex collinus Wang, M. 2003: 432, figs. 119-122 (w.q.) PHILIPPINES.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Description=

Worker

Holotype. TL 3.51, HL 0.88, HW 0.84, CI 95, SL 0.86, SI 102, PW 0.59, AL 0.91. Paratypes. TL 3.36-3.84, HL 0.82-0.94, HW 0.77-0.94, CI 93-103, SL 0.80-0.94, SI 98-110, EL 0.14-0.18, PW 0.54-0.62, AL 0.86-1.00, PPW 0.2.5-0.26, PPL 0.25-0.28, PPI 89-100 (n = 40).

Mandibles usually smooth and shining but sometimes with a few longitudinal rugae. Dentition of the masticatory margin of mandible: the strongest apical + the second strongest preapical + a long diastema + two small teeth that are subequal in size. Basal margin of mandible somewhat straight, lacking a distinct tooth. Clypeus depressed and smooth, usually unsculptured but very rarely with a longitudinal median carina. Anterior clypeal margin usually with a median denticle and two others on each side but sometimes with a lateral denticle indistinct or two lateral denticles fused into a larger one. Ventral surface of clypeus with a low, broadbased, central tooth. Palp formula 1,3. Frontal carinae extending to the level of the posterior margins of eyes. Antennal scrobes absent. Frontal lobes weak; thus, the antennal articulations are almost entirely exposed. Antennal scapes, when lying on the dorsal head, slightly surpassing the occipital margin of head. Eyes moderate, usually containing six to seven ommatidia in the longest row. Pronotum with a pair of short but acute spines that are slightly variable in length. Propodeum armed with a pair of short spines that are about equal to or slightly longer than the pronotal ones. Metapleural lobes subtriangular. In both profile and dorsal view, the dorsum of alitrunk convex, that is, pronotum plus mesonotum forming a convex dorsum. Petiole node in profile with a fairly long anterior peduncle, its anterodorsal angle higher than the posterodorsal. Postpetiole in profile rounded dorsally, in dorsal view slightly longer than broad, or about as long as broad, but always slightly broadening from front to back. Dorsum of head, except for a few punctures bordering the frontal carinae, smooth and highly polished. Dorsum of alitrunk unsculptured and highly polished. Very rarely, the dorsal surfaces of head and alitrunk with a few feeble punctures. Petiole, postpetiole, and gaster smooth and shining. A weak longitudinal ruga usually present on each side of the petiole but absent in few specimens. Dorsal surfaces of head and alitrunk with some sparse erect or suberect hairs. One or two pairs of hairs present on the dorsal surfaces of petiole node and postpetiole, respectively. First gastral tergite lacking hairs. Three pairs of forward-projecting hairs present near the anterior clypeal margin. Scapes and tibiae with erect to suberect short hairs. Color uniformly reddish-brown.

Queen

TL 4.04-4.38, HL 0.87-0.94, HW 0.85-0.96, CI 94-105, SL 0.84-0.94, SI 98-102, EL 0.22-0.26, PW 0.76-0.84, AL 0.92-1.26, PP\Y 0.27-0.30, PPL 0.26-0.29, PPI 100-111 (n = 8).

Generally similar to worker except for normal caste differences. In addition, pronotum unarmed; propodeal armaments toothlike, shorter than those of the conspecific worker.

Type Material

Wang (2003) - Holotype worker. Museum of Comparative Zoology. Philippines: Dumaguete (J. W. Chapman). Paratypes. 40 workers and nine queens (MCZC, The Natural History Museum, Musee d'Histoire Naturelle Genève).40 workers and nine queens with same data as holotype .

References

  • Wang, M. 2003. A Monographic Revision of the Ant Genus Pristomyrmex (Hymenoptera:Formicidae). Bull. Mus. Comp. Zool. 157(6): 383-542 (page 432, figs. 119-122 worker, queen described)