Pristomyrmex distinguendus

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

Nothing is known about the biology of Pristomyrmex distinguendus.

Identification

Zettel (2006) - Ventral surface of clypeus with strongly prominent tooth at centre. Pronotum with pair of short teeth (PSL1 0.02-0.05), which shorter than propodeal spines (PSL2 0.05-0.09). Dorsum of head and alitrunk smooth and polished, with many long hairs; dorsum of head with scarce punctures (hair pits). Antennal scrobe present, its ventral margin defined by a ridge reaching at least level of centre of eye; petiolar node with two or three pairs of hairs.

This species is similar to Pristomyrmex collinus, but differs in a good number of characteristics: The dorsal surface of the head and the alitrunk has many long setae. The pronotal spines are distinctly shorter than the propodeal spines. The antennal scrobes are present and late-rally delimited by a ridge reaching caudally at least to level of centre of eye. The clypeus has three teeth, with the median tooth longest (observed also in one specimen of P. collinus, in which dentation of clypeus is more variable than in P. distinguendus).

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.

  • distinguendus. Pristomyrmex distinguendus Zettel, 2006: 61, figs. 1, 2 (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 3.32, HL 0.80, HW 0.81, CI 101, SL 0.80, SI 100, EL 0.17, PW 0.58, AL 0.87, PPW 0.26, PPL 0.27, PPI 96. – Paratype workers (n = 7): TL 2.84-3.41, HL 0.68-0.81, HW 0.69-0.83, CI 100-103, SL 0.70-0.85, SI 100-104, EL 0.15-0.19, PW 0.48-0.59, AL 0.75-0.90, PPW 0.21-0.28, PPL 0.23-0.27, PPI 91-103.

Head: Mandibles smooth and shiny. Masticatory margin of mandible with four teeth: strongest apical + second strongest preapical + long diastema + two small basal teeth of similar size that are more or less fused. Basal margin of mandible almost straight, lacking distinct tooth. Clypeus with median longitudinal carina in caudal half (specimens from Luzon) or along entire length (specimen from Leyte). Anterior clypeus margin with median tooth and one pair 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. Frontal lobes very weak; thus, antennal insertion almost entirely exposed. Antennal scapes, when lying on dorsum of head, slightly surpassing occipital margin of head. Eyes containing c. 8-10 ommatidia in longest row. Pronotum with pair of short teeth, PSL1 0.02-0.05. Propodeum with pair of spines, PSL2 0.05-0.09. Metapleural lobes subtriangular, acute. Dorsum of alitrunk distinctly convex. Petiole in profile with fairly long peduncle, node with weakly developed angles, anterodorsal one on slightly higher level than posterodorsal one. Postpetiole in profile rounded dorsally, in dorsal view broadening from front to back. Dorsum of head smooth and polished, with scattered hair pits which are small in specimens from Luzon and relatively large in specimen from Leyte; on scrobal areas, at least anteriorly, with some transverse rugae. Dorsum of alitrunk smooth and polished, with only very fine hair pits. Petiole, postpetiole, and gaster smooth and shiny. Dorsal surfaces of the head and alitrunk with numerous long erect or suberect hairs. Dorsum of petiolar node with 2-3 pairs of hairs; dorsum of postpetiole with 1-2 pairs. 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 reddish-brown.

Type Material

Holotype (worker): Luzon: Camarines Sur Pr., 20 km E Naga, E Carolina, slopes of Mt. Isarog, 4.III.1999, leg. F. Seyfert (#19) (Naturhistorisches Museum Wien, Vienna); paratypes: Laguna Pr., Los Baños, Mt. Makiling, from UPLB to Mud Spring, 18.XI.1999, leg. H. Zettel (#207), 1 worker (CZW); Laguna Pr., Los Baños, Mt. Makiling, 500-1144 m, 14.XI. 1993, leg. H. Zettel (#21a), P. collinus det. Wang M., 1 worker (CZW); Quezon Pr., Atimonan, Quezon NP, Old Zigzag Road, 27-28.I.2002, leg. H. Zettel (#300), 4 workers (CZW, UPLB); Leyte: Baybay, Leyte State University, c. 50-100 m, Calbiga-a River, 20-21.III.2005, leg. H. Zettel & C. Pangantihon (#422), 1 worker (CZW).

References