Pristomyrmex modestus

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

The holotype was collected from a forest.

Identification

Wang (2003) - Worker. Pronotum with a pair of moderately long, robust spines; dorsal surfaces of head and alitrunk, as well as the two sides of pronotum, with a coarse rugoreticulum; petiole node in profile somewhat transrectangular, slightly longer than high, with seven to eight foveolate punctures.

This species must have evolved from the ancestor of Pristomyrmex costatus. It differs from P. costatus in the workers as follows: P. modestus - Petiole node in profile longer than high, somewhat rectangular, with the anterodorsal angle on approximately the same level as the posterodorsal. Dorsum and sides of petiole node with seven to eight foveolate punctures. P. costatus - Petiole node in profile higher than long; its anterodorsal angle is distinctly higher than the posterdorsal. Dorsum and sides of petiole node without foveolate punctures.

A member of the Quadridens species group

Keys including this Species

Key to Pristomyrmex workers

Distribution

Distribution based on Regional Taxon Lists

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

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Explore Overview of Pristomyrmex 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.

Images from AntWeb


Holotype of Pristomyrmex modestus. Worker. Specimen code casent0901718. Photographer Will Ericson, uploaded by California Academy of Sciences.	Owned by NHMUK, London, UK.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

modestus. Pristomyrmex modestus Wang, M. 2003: 452, figs. 148-149 (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 4.00, HL 0.99, HW 0.92, CI 93, SL 0.95, SI 103, EL 0.19, PW 0.64, AL 1.04, PPW 0.35, PPL 0.35, PPI 100.

Mandibles with a few longitudinal rugae. Masticatory margin of mandible with two adjacent strong apical teeth + a long diastema + one broad, somewhat concave basal tooth. Basal margin of mandible lacking a distinctly curved lobe or tooth. Clypeus with a strong median carina. Anterior clypeal margin with a median denticle and three others on each side. Ventral surface of clypeus with a short transverse ruga. Frontal carinae strong, extending to the level of the posterior margins of the eyes. Antennal scrobes indistinct. Frontal lobes weak so that the antennal articulations are almost entirely exposed. Antennal scapes, laid on the dorsal head, slightly surpassing the occipital margin of head. Eyes rather large. Pronotal spines robust, ca. 0.14, shorter than the distance between their bases. Propodeal spines acute, slender, ca. 0.11. Metapleural lobes developed, prominent, ca. 0.14, each with a rounded apex. In profile view, petiole node slightly longer than high, somewhat transrectangular, with the anterodorsal angle on approximately the same level as or weakly higher than the posterodorsal; in dorsal view, petiole node longer than broad. Postpetiole in profile rounded dorsally; in dorsal view, approximately quadrate and about as long as broad. Dorsal surfaces of head and alitrunk, as well as the two sides of pronotum, entirely sculptured with coarse rugoreticulum. Dorsum and the sides of petiole node with seven to eight large foveolate punctures. Postpetiole with a few shallow foveolate punctures. Gaster unsculptured, smooth, and shining. Dorsal surfaces of head and alitrunk with numerous erect or suberect hairs. Petiole node and postpetiole each with a few pairs of hairs. First gastral tergite lacking erect or suberect hairs. A few pairs of forward-projecting hairs present near the anterior clypeal margin. Scapes and tibiae with sparse erect or suberect hairs. Color reddish-brown.

Type Material

Holotype Worker. The Natural History Museum. Malaysia: Sarawak, 4th Division, Gn. Mulu N.P., Kerangas for., leaf litter, 19.iii.1978 (H. Vallack).

References

Wang, M. 2003. A Monographic Revision of the Ant Genus Pristomyrmex (Hymenoptera:Formicidae). Bulletin of the Museum of Comparative Zoology 157(6): 383-542 (page 452, figs. 148-149 worker described)

References based on Global Ant Biodiversity Informatics

Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58
Wang M. 2003. A Monographic Revision of the Ant Genus Pristomyrmex (Hymenoptera:Formicidae). Bulletin of the Museum of Comparative Zoology 157(6): 383-542.