Pristomyrmex rugosus

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Pristomyrmex rugosus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Pristomyrmex
Species: P. rugosus
Binomial name
Pristomyrmex rugosus
Zettel, 2006

Nothing is known about the biology of Pristomyrmex rugosus.

Identification

Zettel (2006) - Ventral surface of clypeus with prominent tooth at centre. Pronotum with pair of long pines (PSL1 0.15-0.17), which are distinctly longer than short propodeal teeth (PSL2 0.04-0.05). Dorsum of head and alitrunk with foveolate-reticulate sculpture or rugoreticuletum, with long, relatively dense pilosity; petiolar node and postpetiolar nodes smooth, each with several pairs of hairs on dorsum. First gastral tergite without erect or suberect hairs.

This species is most similar to Pristomyrmex sulcatus, but differs in having relatively long pronotal spines, dorsally more rounded node of petiole, and relatively large eyes with more ommatidia (10-12 vs. 6-7 in P. sulcatus). From typical P. sulcatus, it can be easily distinguished by the numerous setae on the petiole and postpetiole and by the more reticulate dorsum of the pro-mesonotum (with coarser longitudinal ridges in syntype of P. sulcatus). However, judging from the specimens deposited in NHMW and identified by M. Wang, P. sulcatus as redescribed and interpreted by Wang (2003) is a variable species and may include further unrecognized taxa. From three other species, which are recorded from the Philippines, the new species differs as follows: from Pristomyrmex bicolor in the much shorter pronotal spines, in smaller size, and the presence of a central tooth on the ventral surface of the clypeus; from Pristomyrmex brevispinosus in the absolutely and relatively longer pronotal spines; and from Pristomyrmex costatus in the presence of a central tooth on the ventral surface of the clypeus, slightly shorter pronotal spines, and more coarse rugoreticulum on dorsum of alitrunk.

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Philippines (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

Nomenclature

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

  • rugosus. Pristomyrmex rugosus Zettel, 2006: 63, figs. 3, 4 (w.) PHILIPPINES.

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

Description

Worker

Holotype worker: TL 4.26, HL 1.05, HW 1.02, CI 98, SL 1.09, SI 106, EL 0.22, PW 0.72, AL 1.14, PPW 0.31, PPL 0.34, PPI 89. – Paratype workers (n = 7): TL 4.01-4.26, HL 0.94-1.05, HW 0.94-1.02, CI 97-101, SL 1.01-1.06, SI 102-107, EL 0.19-0.21, PW 0.63-0.70, AL 1.00-1.12, PPW 0.27-0.30, PPL 0.30-0.32, PPI 90-97.

Head : Mandibles more or less striate. Masticatory margin of mandible with four teeth: strongest apical + second strongest preapical + long diastema + two small basal teeth of similar size. Basal margin of mandible almost straight, lacking distinct tooth. Clypeus with strong median longitudinal carina and one pair of more or less developed lateral carinae. Anterior clypeus margin with median tooth and three pairs of lateral teeth. Ventral centre of clypeus with strongly prominent tooth. Palp formula 1, 3. Frontal carinae strong, extending caudad further than level of posterior eye margins. Antennal scrobes present, laterally delimited by distinct ridge reaching caudally at least to level of centre of eye. Both frontal carinae and lateral ridge confluent with strong rugoreticulum of head. Frontal lobes absent, antennal insertion entirely exposed. Antennal scapes, when lying on dorsum of head, surpassing occipital margin of head. Eyes containing 10-12 ommatidia in longest row. Pronotum with pair of relatively long spines, PSL1 0.15-0.17. Propodeum with pair of teeth, PSL2 0.04-0.05. Metapleural lobes subtriangular, apex weakly to moderately rounded. Dorsum of alitrunk anteriorly convex, posteriorly straight. Petiole in profile with fairly long peduncle, node with weakly developed, high anteriodorsal angle, posteriodorsally rounded. Postpetiole in profile rounded dorsally, in dorsal view broadening from front to back. Dorsum of head, except for transversely rugous scrobal areas, and alitrunk with coarse rugoreticulum. Sides of pronotum similarly reticulate, but rugae less high. Petiole, postpetiole, and gaster smooth and shiny. Dorsal surfaces of head, alitrunk, petiole, and postpetiole with numerous long erect or suberect hairs. First gastral tergite lacking erect or suberect hairs. A few pairs of forward projecting hairs present near anterior clypeal margin. Scapes and tibiae with numerous erect to suberect hairs. Colour dark reddish-brown.

Type Material

Holotype (worker): Leyte: Leyte Pr., Baybay, Mt. Pangasugan, Calbiga-a River, 50-200 m, 12.II. 2000, leg. H. Zettel (#236) (Naturhistorisches Museum Wien, Vienna); paratypes: same data, 5 workers (CZW); same locality, c. 50-100 m, Calbiga-a River, 20-21.III.2005, leg. H. Zettel & C. Pangantihon (#422), 2 workers (CZW, USC).

References