Pristomyrmex quindentatus

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

Pristomyrmex quindentatus casent0901724 p 1 high.jpg

Pristomyrmex quindentatus casent0901724 d 1 high.jpg

Specimen Labels

This species has been collected in rainforest.

Identification

Wang (2003) - Worker. Masticatory margin of mandible with five teeth; pronotum with a pair of triangular teeth; dorsal surfaces of head and alitrunk with scattered foveolate punctures.

Pristomyrmex quindentatus is closely related to Pristomyrmex occultus. The two species occur in the Oriental region. Their workers share a critical character, that is, the masticatory margin of mandible with an apical tooth + a pre apical tooth + a diastema + three small denticles of similar size; this dentition is not seen in all other Pristomyrmex species, except in Pristomyrmex eduardi. But P. quindentatus and P. occultus can be separated from P. eduardi in the workers in having a pair of pronotal teeth.

The worker of P. quindentatus differs from that of P. occultus as follows: P. quindentatus - Dorsal surfaces of head and alitrunk only with scattered, shallow foveolate punctures; dorsum of alitrunk with an unsculptured median longitudinal strip. Anterior clypeal margin with a truncated median tooth. A lateral carina lacking or vestigial on each side of the petiole node. SL 0.76-0.80, SI 94-100. P. occultus - Dorsal surfaces of head and alitrunk entirely covered with coarse rugoreticulum. Median tooth on the anterior clypeal margin not truncated. Petiole node with a lateral longitudinal carina on each side. SL 0.72-0.75, SI 87-93.

Pristomyrmex quindentatus may have evolved from the ancestor of Pristomyrmex quadridens. Pristomyrmex quindentatus can be separated from P. quadridens as follows: the masticatory margin of the mandible possesses five teeth in the workers and queens of P. quindentatus but at most four teeth in P. quadridens; in addition, the propodeum is armed with a pair of short spines in the workers of P. quindentatus but a pair of teeth in P. quadridens.

A member of the Quadridens species group

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Indonesia (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

Males have yet to be collected.

Nomenclature

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

  • quindentatus. Pristomyrmex quindentatus Wang, M. 2003: 467, figs. 167-170 (w.q.) INDONESIA (Seram I.).

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 3.54, HL 0.86, H\V 0.84, CI 98, SL 0.79, SI 94, EL 0.12, PW 0.56, AL 0.83.

Worker. TL 3.10-3.54, HL 0.81-0.86, HW 0.79-0.84, CI 96-98, SL 0.76-0.80, SI 94-100, EL 0.11-0.12, PW 0.53-0.56, AL 0.78-0.86, PPW 0.22-0.23, PPL 0.21-0.22, PPI 100-105 (n = 6).

Mandibles smooth and shining, except for a few longitudinal rugae. Masticatory margin of mandible with five teeth arranged as the strongest apical + the second strongest preapical + a diastema + three small denticles of similar size (sometimes three small denticles are fused together so that they are not clearly visible; or, one of them is weak or worn down, but the length of diastema is slightly shorter than the distance covered by these three teeth). Basal margin of mandible lacking toothlike prominence s. Clypeus depressed and smooth, but the median carina of the frontal area extending a little to the clypeus. Anterior clypeal margin usually with a broad, truncated median denticle and two to three others on each side. Ventral center of clypeus with a prominent tooth. Palp formula 1,3. Frontal carinae strong, extending to the level of the posterior margins of eyes. Slightly impressed scrobal areas present lateral to the frontal carinae. Frontal lobes weak; thus, the antennal articulations are almost entirely exposed. Antennal scapes, laid on the dorsal head, just surpassing the occipital margin of head. Eyes moderately sized. Occipital margin feebly concave. Pronotum with a pair of triangular teeth. Propodeum with a pair of short spines that are about two to three times the length of pronotal armaments. Metapleural lobes somewhat rounded. Petiole node in profile with a fairly long anterior peduncle; its anterodorsal angle is on a higher level than the posterodorsal. Postpetiole in profile rounded dorsally, in dorsal view about quadrate. Dorsum of head, except for the shallow scrobes, with numerous scattered foveolate punctures. Dorsum of alitrunk possessing scattered foveolate punctures, usually with a smooth and unsculptured median strip. Petiole smooth and shining, with a weak longitudinal ruga on each side. Postpetiole and gaster unsculptured. Dorsal surfaces of head and alitrunk with numerous erect or suberect short hairs. Two pairs of hairs usually present on the dorsum of petiole node, and a few pairs on the dorsum of postpetiole. First gastral tergite lacking or bearing few suberect hairs. A few pairs of forward-projecting hairs present near the anterior clypeal margin. Scapes and tibiae with numerous erect to suberect short hairs. Color reddish-brown.

Queen

TL 3.64, 3.70; HL 0.83, 0.83; HW 0.82, 0.83; CI 99, 100; SL 0.72, 0.78; SI 88, 94; EL 0.18, 0.19; PW 0.64, 0.64; AL 0.97, 1.00; PPW 0.23, 0.23; PPL 0.22, 0.23; PPI 100, 105 (n = 2).

Generally similar to worker, except for normal caste differences. In addition, pronotum unarmed; propodeal armaments toothlike, shorter than those in the conspecific worker, and the dorsum of alitrunk lacking an unsculptured median longitudinal strip.

Type Material

Holotype worker. Museum of Comparative Zoology. Indonesia: Seram, above Haruru, near Masohi, rainforest, .50 to 150 m, 18.iii.1981 (W. L. Brown). Paratypes, five workers and two queens MCZC.

References

  • Wang, M. 2003. A Monographic Revision of the Ant Genus Pristomyrmex (Hymenoptera:Formicidae). Bull. Mus. Comp. Zool. 157(6): 383-542 (page 467, figs. 167-170 worker, queen described)