Pristomyrmex occultus

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

Pristomyrmex occultus casent0901720 p 1 high.jpg

Pristomyrmex occultus casent0901720 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Pristomyrmex occultus.

Identification

Wang (2003) - Worker. Masticatory margin of mandible with five teeth; pronotum with a pair of triangular short spines; dorsal surfaces of head and alitrunk, as well as the two sides of pronotum, with coarse rugoreticulum.

Pristomyrmex occultus is a sibling species of Pristomyrmex quindentatus. The two species are all from the Oriental region. The separation of the two species is discussed under P. quindentatus.

Pristomynnex occultus is also very similar in appearance to Pristomyrmex brevispinosus. But in the workers of P. occultus, the masticatory margin of the mandible possesses five teeth, the length of the masticatory margin covered by three small denticles is slightly longer than that of diastema, and the propodeum is armed with a pair of fairly long spines. In P. brevispinosus, the masticatory margin of the mandible has four teeth, the length of the masticatory margin covered by two basal denticles is not longer than that of diastema, and the propodeum is armed with a pair of triangular teeth.

A member of the Quadridens species group

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo (type locality), Indonesia, Malaysia.

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

Queen and Male are unknown.

Nomenclature

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

  • occultus. Pristomyrmex occultus Wang, M. 2003: 455, figs. 152-153 (w.) BORNEO.

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 3.10, HL 0.84, HW 0.81, C1 96, SL 0.72, SI 89, EL 0.10, PW 0.56, AL 0.80. Workers. TL 3.04-3.2.3, HL 0.84-0.88, HvV 0.80-0.84, C1 93-98, SL 0.72-0.75, SI 87-93, EL 0.10-0.13, PW 0.52-0.56, AL 0.76-0.80, PPW 0.22-0.24, PPL 0.20-0.22, PP1 109-120 (n = 5).

Mandibles generally smooth and shining, with a few basal longitudinal rugae. Masticatory margin of mandible with five teeth arranged as the strongest apical + the second strongest preapical + a diastema + three small dentides of similar size of which the middle one is sometimes weak (i.e., smaller than the two others) or worn down, but the length of the masticatory margin covered by the three denticles is longer than the diastema. Basal margin of mandible lacking a toothlike prominence . Clypeus depressed, smooth, and shining. Anterior clypeal margin with a median denticle and two to three others on each side. Ventral center of clypeus with a strongly prominent tooth. Frontal carinae strong, extending to the level of the posterior margins of eyes. Antennal scrobes shallow. Frontal lobes weak; thus, the antennal articulations are almost entirely exposed. Antennal scapes, laid on the dorsal head , just reaching to the occipital margin of head. Eyes moderately sized, containing five to six ommatidia in the longest row. Occipital margin in full-face view feebly concave. Pronotum armed with a pair of triangular short spines. Propodeal spines acute, about two times the length of the pronotal teeth. Metapleural lobes prominent and rounded. Dorsum of alitrunk in dorsal view somewhat depressed. Petiole node high in profile, with a fairly long anterior peduncle; its anterodorsal angle higher than the posterodorsal. Subpetiole with a narrow, long, semitranslucent lamella. Postpetiole in profile rounded dorsally, in dorsal view slightly broader than long. Dorsal surfaces of head and alitrunk, as well as the two sides of pronotum, with coarse, strongly sculptured rugoreticulum, but the scrobal areas lacking this sculpture. Petiole and postpetiole smooth and shining, except for a lateral longitudinal carina on each side that separates the tergite from the sternite. Gaster unsculptured. Dorsal surfaces of head and alitrunk with numerous erect or suberect hairs. Two pairs of hairs present on the dorsum of petiole node and usually two to three pairs on the dorsum of postpetiole. First gastral tergite lacking erect or suberect hairs. A few of forward-projecting hairs present near the anterior clypeal margin. Scapes and tibiae with some erect to suberect short hairs. Color reddish-brown.

References

  • Wang, M. 2003. A Monographic Revision of the Ant Genus Pristomyrmex (Hymenoptera:Formicidae). Bull. Mus. Comp. Zool. 157(6): 383-542 (page 455, figs. 152-153 worker described)