Pristomyrmex pollux

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Pristomyrmex pollux
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Pristomyrmex
Species: P. pollux
Binomial name
Pristomyrmex pollux
Donisthorpe, 1944

Pristomyrmex pollux casent0901714 p 1 high.jpg

Pristomyrmex pollux casent0901714 d 1 high.jpg

Specimen Labels

Nothing is known about the biology of Pristomyrmex pollux.

Identification

Wang (2003) - Worker. Masticatory margin of mandible with four teeth (an apical + a preapical + two broad-based short teeth of similar size), lacking a distinct diastema; eyes small, with three to four ommatidia in the longest row; propodeal spines long, strongly upcurved at their apices.

Pristomyrmex pollux is known from Malaya and Sabah. It must have evolved from a P. picteti-like ancestor. The workers of this species can be immediately recognized by possessing a pair of distinct propodeal spines that are long, strongly upcurved at their apices (i.e., hook-like), and laterally compressed. This character is unique in the genus Pristomyrmex.

A member of the Umbripennis species group

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo, Indonesia, Malaysia (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

Male

Nomenclature

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

  • pollux. Pristomyrmex pollux Donisthorpe, 1944d: 83 (m.) WEST MALAYSIA. Wang, M. 2003: 521 (w.q.).

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

Description

Worker

Wang (2003) - TL 6.26-6.80, HL 1.42-1.54, HW 1.42- 1.58, CI 95- 104, SL 1.40- 1.52, SI 96- 101, EL 0.06-0.08, PW 0.90-0.96, AL 1.58- 1.90, PPW 0.39-0.43, PPL 0.39-0.43, PPI 100-105 (n =28).

Mandibles with a few longitudinal rugae. Basal margin of mandible with a broad, short, somewhat truncated, prominent lobe. Clypeus with a median longitudinal carina that does not reach the posterior clypeal margin. Frontal area unsculptured. Anterior margin of the median portion of clypeus with a median denticle and three (sometimes two) others on each side. Ventral surface of clypeus with a coarse transverse carina. Palp formula 1,3. Frontal carinae strong, extending to the level of the posterior margins of eyes. Scrobal areas smooth, present lateral to the frontal carinae . Frontal lobes present, partially covering the condylar bulbs of holding antennal scapes. Antennal scapes, when lying on the dorsal head, just beyond the occipital margin. Lamella, encircling the base of antennal scape, with a broad and deep notch on the center of the dorsal surface. Eyes small, usually with three, at most four, ommatidia in the longest row. Occipital margin straight or feebly concave in full-face view. Pronotum unarmed. Propodeum with a pair of long spines that are strongly upcurved at their apices (i.e., hooklike) and laterally compressed. Metapleural lobes prominent and somewhat rounded. Petiole node in profile distinctly longer than high, with a long anterior peduncle; its anterodorsal angle is on approximately the same level as the posterodorsal. In dorsal view, petiole node longer than broad. Subpetiole with a narrow, semitranslucent lamella. Postpetiole in profile higher than long, rounded dorsally, in dorsal view broadening from front to back. Dorsum of head, except for scrobal areas and frontal area, with foveolate-reticulate sculpture. Antennal scapes with longitudinal rugae along their dorsal margins. Dorsum of alitrunk as well as the sides of pronotum with numerous foveolate punctures that are often close to each other. Sides of the rest of alitrunk with some scattered punctures. Petiole smooth and shining, but with a longitudinal ruga on each side. Postpetiole and gaster smooth and shining. Dorsal surfaces of head, alitrunk, petiole, and postpetiole with numerous erect or suberect hairs. A row of forward-projecting long hairs present near the anterior clypeal margin. Scapes and tibiae with some erect or suberect short hairs. First gastral tergite lacking erect or suberect hairs. Color yellow-brown to reddish-brown.

Queen

Wang (2003) - A single queen (BMNH) was examined. It was collected in Penang, Malaysia, by C. E. Bryant in October 1913 (i.e., the collecting locality and the collector name for this specimen are the same as the holotype male of P. pollux): TL ca. 7.66, HL 1.64, HW 1.69, CI 103, SL 1.56, SI 92, EL 0.29, PW 1.42, AL 2.14.

This queen possesses the following characters: (1) dentition of the masticatory margin and basal margin of mandible as in the previously mentioned worker; (2) dentition of the anterior clypeal margin as in the previously mentioned worker; (3) clypeus with a median carina that does not reach the posterior clypeal margin; (4) ventral surface of clypeus with transverse ruga; (5) frontal lobes and frontal carinae as in the previously mentioned worker; (6) lamella encircling the base of antennal scape as in the previously mentioned worker; (7) antennal scapes with longitudinal rugae along their dorsal margins; (8) propodeum with a pair of robust, rather long spines that are longer than the distance between their bases; (9) metapleural lobes as in the previously mentioned worker; (10) petiole and postpetiole as in the previously mentioned worker; and (11) dorsum of head, except for the scrobal are as, with foveolate-reticulate sculpture. In other words, except for normal caste differences and the propodeal spines that are neither laterally compressed nor upcurved at their apices, other characters are gene rally similar to those in the previously mentioned worker.

Male

Wang (2003) - TL 5.60-5.92, HL 0.85-0.88, HW 0.68-0.70, CI 80-80, SL 0.38-0.41, SI 54-60, HWE 0.86-0.88, EL 0.44-0.44, PW 1.26-1.36, AL 2.00-2.20, PPW 0.35-0.38, PPL 0.42-0.44, PPI 80-90 (n = 3).

Head in profile high and thick, in full-face view, excluding eyes, much longer than broad, and including the eyes about as long as broad. Clypeus convex and arched in middle without a median longitudinal carina. Palp formula 1,3; maxicillary palp long. Maximum diameter of the median ocellus 0.12. Scapes longer than the other antennal segments, except for the apical ones. On the mesonotum, notauli rather wide and deep, showing a Y shape, separated into small cells by narrow transverse ridges; parapsidal furrows absent. Scuto-scutellar sulcus wide, separated into small cells by seven to eight narrow ridges. Propodeum with a pair of robust, broad-based, rather long spines. Metapleural lobes prominent and somewhat rounded. Petiole node in profile distinctly longer than high with a long anterior peduncle. Postpetiole in profile slightly longer than high with a convex dorsum, in dorsal view rectangular and distinctly longer than broad. Subpostpetiole with a blunt, toothlike prominence. Dorsum of head with numerous small foveolate punctures that sometimes are coarse and dense. Pronotum with small, coarse, and dense foveolate punctures. Mesoscutum with some scattered, small, shallow foveolate punctures. Mesoscutellum with dense, coarse foveolate punctures. Propodeum with some irregular coarse rugae. Middle and hind tibiae without any spurs. Each side of petiole with a coarse longitudinal ruga, a few irregular short rugae, and some foveolate punctures. Sides of postpetiole with some small, weak foveolate punctures. All dorsal surfaces with abundant erect or suberect stiff long hairs. Color blackish-brown; hairs blackish-brown; wings rather smoky. (Note: In the holotype, the right antenna is abnormal, with 11 segments, while the left one has 12.)

Type Material

Wang (2003) - Holotype male, Malaysia: Penang, 6.xi.1913 (G> E. Bryant) (The Natural History Museum) [examined].

References

References based on Global Ant Biodiversity Informatics

  • Donisthorpe H. 1944. Two new species of Pristomyrmex Mayr (Hym. Formicidae), with some notes on the genus. Proceedings of the Royal Entomological Society of London. Series B 13: 81-84.
  • 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). Bull. Mus. Comp. Zool. 157(6): 383-542.
  • Wang M. 2003. A monographic revision of the ant genus Pristomyrmex (Hymenoptera:Formicidae). Bulletin of the Museum of Comparative Zoology 157(6):383-542