Pristomyrmex bispinosus

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Pristomyrmex bispinosus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Pristomyrmex
Species: P. bispinosus
Binomial name
Pristomyrmex bispinosus
(Donisthorpe, 1949)

Pristomyrmex bispinosus casent0104922 profile 1.jpg

Pristomyrmex bispinosus casent0104922 dorsal 1.jpg

Specimen labels

This species has been collected from trees and the ground in forest habitat.

Identification

Wang (2003) - Worker. Dorsal surfaces of head and alitrunk mostly unsculptured; mesonotum unarmed, at most weakly tuberculate; alitrunk in profile with a convex promesonotum and a deeply concave propodeal dorsum; propodeal spines in dorsal view forming a divergent fork.

It can be easily separated from its two relatives, Pristomyrmex trispinosus and Pristomyrmex browni, in the workers, as follows: In P. bispinosus, the dorsal surfaces of the head and the alitrunk are smooth and shining, except for some short rugae around the antennal fossae, on the genae, and sometimes around the centrical disc of the head; but in P. trispinosus and P. browni, the dorsal surfaces of the head and the alitrunk are entirely sculptured with regular striations.

A member of the Trispinosus species group

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Malagasy Region: Mauritius (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

Male

Nomenclature

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

  • bispinosus. Dodous bispinosus Donisthorpe, 1949e: 272 (w.) MAURITIUS. Combination in Pristomyrmex: Brown, 1971a: 3. See also: Wang, M. 2003: 484.

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 4.36-4.82, HL 1.14-1.20, HW 1.08-1.16, CI 90-100, SL 1.32-1.40, SI 118-130, EL 0.22-0.24, PW 0.70-0.75, AL 1.14-1.20, PPW 0.28-0.32, PPL 0.26-0.28, PPI 107-115 (n = 11).

Mandibles smooth and shining. Masticatory margin of mandible with four teeth arranged as the strongest apical + the second strongest preapical + a relatively short diastema + a small denticle + a relatively long diastema + a small basal denticle. Basal margin of mandible lacking a toothlike pronlinence. Anterior margin of the median portion of clypeus with at least five denticles, but sometimes two lateral denticles are fused into a broad, truncated lobe. Two ends of anterior clypeal margin each with a strong, subtriangular tooth. Ventral surface of clypeus usually with a transverse ruga. Clypeus usually unsculptured, but frontal area usually with three to four short carinae that often extend to the posterior clypeal margin. Palp formula 1,2. Frontal carinae absent. Antennal scrobes absent. Frontal lobes nearly completely absent so that the antennal articulations are almost entirely exposed. Antennal scapes long, when lying on the dorsal head surpassing the occipital margin by about one-fourth of their length. Eyes usually containing 11 to 12 ommatidia in the longest row. Occipital margin slightly concave. Alitrunk in profile with a convex promesonotum and a deeply concave propodeal dorsum. Pronotum armed with a pair of fairly long, acute spines. Propodeum with a pair of long spines that, in dorsal view, are joined together at the base but are divergent along their length so that they form a fork. Mesonotum unarmed but sometimes with tubercles. Promesonotal suture or impression present. Metapleural lobes dentiform. Petiole in profile with a long anterior peduncle; anterodorsal angle of the node is higher than the posterodorsal. Postpetiole in profile usually with a curved anterior and dorsal surface, in dorsal view slightly broader than long. Dorsum of head mostly smooth and shining but with some regular short lugae present around the antennal fossae, on genae and sometimes around the centrical disc. Dorsum of alitrunk as well as the sides of pronotum usually smooth and shining, but the sides of the rest of alitrunk usually with some regular short rugae. Petiole unsculptured. Dorsum of postpetiole smooth and shining. Gaster unsculptured. All dorsal surfaces with numerous erect or suberect hairs. A row of forward-projecting hairs present near the anterior clypeal margin. Scapes and tibiae with some short hairs. Color yellow-brown, but sometimes reddish-brown.

Type Material

Wang (2003) - Lectotype worker, Mamitius: Le Pouce Mt., 2.xi.1948 (R. Mamet) (The Natural History Museum), here designated, [examined].

References

  • Brown, W. L., Jr. 1971a. Characters and synonymies among the genera of ants. Part IV. Some genera of subfamily Myrmicinae (Hymenoptera: Formicidae). Breviora 365: 1-5 (page 3, Combination in Pristomyrmex)
  • Donisthorpe, H. 1949f. A new Camponotus from Madagascar and a small collection of ants from Mauritius. Ann. Mag. Nat. Hist. 12(2): 271-275 (page 272, worker described)
  • Wang, M. 2003. A Monographic Revision of the Ant Genus Pristomyrmex (Hymenoptera:Formicidae). Bull. Mus. Comp. Zool. 157(6): 383-542 (page 484, figs. 195-196 worker described)