Pristomyrmex levigatus

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Pristomyrmex levigatus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Pristomyrmex
Species: P. levigatus
Binomial name
Pristomyrmex levigatus
Emery, 1897

Pristomyrmex levigatus casent0199666 p 1 high.jpg

Pristomyrmex levigatus casent0199666 d 1 high.jpg

Specimen Labels

Synonyms

This species occurs in rainforest and has been collected in a litter sample.

Identification

Wang (2003) – Worker. Masticatory margin of mandible lacking a diastema and possessing four teeth, of which the third tooth, counting from the apex, smallest; HW 0.62-0.78, HL 0.64-0.78; eyes with five to eight ommatidia in the longest row; pronotum unarmed ; propodeum with a pair of teeth or short spines; petiole with a lateral longitudinal carina on each side; subpetiole lacking a pinlike long process; dorsal surfaces of head and alitrunk smooth and shining.

Pristomyrmex levigatus appears to be a basal species within the levigatus group. Many species, such as P. acerosus, P. boltoni, P. inermis, P. largus, P. lucidus, P. mandibularis, P. minusculus, P. obesus, and P. simplex, may have evolved from a P. levigatus-like ancestor. The workers of these species are separable from those of P. levigatus as follows: P. levigatus differs from both Pristomyrmex simplex and Pristomyrmex obesus by lacking foveolate punctures on the dorsal surfaces of the alitrunk and the head between the frontal carinae. In P. levigatus, the eyes are larger, usually containing five to eight ommatidia in the longest row but two to three in Pristomyrmex boltoni. Pristomyrmex levigatus is smaller (HW < 0.80, HL < 0.80) than Pristomyrmex largus and Pristomyrmex lucidus (HW > 0.90, HL > 0.90). Pristomyrmex minusculus bears a pair of pronotal teeth that are not seen in P. levigatus. A pair of propodeal teeth or short spines are present in P. levigatus, but absent in Pristomyrmex inermis. Pristomyrmex levigatus possesses a longitudinal ruga on each side of the petiole node that is not seen in Pristomyrmex mandibularis. Finally, the subpetiole of P. levigatus does not have a pinlike long process that is distinct in Pristomyrmex acerosus.

A member of the Levigatus species group

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Micronesia (Federated States of), New Guinea (type locality), Philippines, Solomon Islands, Wallis and Futuna Islands.

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Pristomyrmex levigatus for further details

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

Nomenclature

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

  • levigatus. Pristomyrmex levigatus Emery, 1897c: 583, pl. 15, fig. 24 (w.) NEW GUINEA. Wang, M. 2003: 501 (q.m.). Senior synonym of mendanai: Wang, M. 2003: 499.
  • mendanai. Pristomyrmex mendanai Mann, 1919: 341 (w.) SOLOMON IS. Junior synonym of levigatus: Wang, M. 2003: 499.

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 2.36- 2.96, HL 0.64-0.78, HW 0.62-0.78, CI 96-106, SL 0.50-0.65, SI 78- 89, EL 0.12-0.16 (very rarely 0.10), PW 0.41-0.52, AL 0.54-0.75, PPW 0.20-0.22, PPL 0.14-0.18, PPI 122-143 (n = 30).

Mandibles usually smooth and shining but with a few fine longitudinal rugae in some specimens. A broad-based triangular short tooth present about midway on the basal margin of the mandible. Frontal area concave, usually unsculptured, but sometimes with a weak median carina. Clypeus flat, unsculptured, smooth, and shining; its anterior margin with a median denticle and two lateral teeth, but sometimes the median tooth is weak or absent. Ventral surface of clypeus lacking any rugae or toothlike prominences. Palp formula 1,3. Frontal carinae distinct, extending to the level of the posterior margins of eyes. Scrobal impressions shallow, present lateral to the frontal carinae. Frontal lobes weak so that the antennal articulations are almost entirely exposed. Antennal scapes, when lying on the head, close to the occipital margin. Eyes moderately sized, with five to eight ommatidia in the longest row. Dorsum of alitrunk in dorsal view flat in the lectotype but convex in some specimens. Pronotum unarmed or at most with blunt tubercles, lacking teeth or spines. Propodeum with a pair of triangular teeth or short spines that are slender, slightly incurved at their apices in the lectotype. Metapleural lobes subtriangular or rounded. Petiole node in profile nodiform with the anterodorsal angle higher than the posterodorsal; its anterior peduncle about as long as the node. Subpetiole with a narrow long flange. In dorsal view, the dorsum of petiole node transoval and broader than long. Postpetiole in profile higher than long, with a rounded dorsum, in dorsal view somewhat transverse-rectangular and broader than long. Dorsum of head smooth and shining but sometimes with a few foveolate punctures bordering the frontal carinae; sometimes a few foveolate punctures present on the genae and around the eyes. Dorsum of alitrunk unsculptured, smooth, and shining. Petiole and postpetiole smooth and shining, each with a longitudinal carina on each side that separates the tergite from the sternite. Gaster unsculptured. Dorsum of head with numerous erect to suberect hairs. Dorsum of alitrunk with some erect or suberect hairs. Dorsal surfaces of petiole node and postpetiole usually with one to two pairs and one to three pairs of hairs, respectively. A few hairs present at the base of the first gastral tergite. A few pairs of forward-projecting hairs present near the anterior clypeal margin. Scapes and tibiae with erect to sub erect short hairs. Color golden-brown or reddish-brown.

Queen

Wang (2003) - TL 2.92-3.34, HL 0.74-0.75, HW 0.76-0.81, CI 101-108, SL 0.60-0.6.5, SI 79-83, EL 0.18-0.19, PW 0.54-0.66, AL 0.80-0.92, PPW 0.23-0.26, PPL 0.18-0.20, PPI 128-133 (n = 5).

Generally similar to worker, except for normal caste differences. Propodeal armaments tuberculate or denticulate, slightly shorter than those in the conspecific worker.

Male

Wang (2003) - Two male specimens, together with 13 workers and two queens, collected in New Guinea (Nadzab, #1083) by E. O. Wilson, constitute a series; each of the two males was originally mounted together with a worker or with a worker and a queen on the same pin: TL 2.48, 2.54; HL 0.50, 0.51; HW 0.53, 0.53; CI 105, 106; SL 0.16, 0.18; SI 30, 34; HWE 0.63, 0.64; EL 0.23, 0.25; PW 0.60, 0.63; AL 0.82,0.84; PP\V 0.18,0.19; PPL 0.15, 0.16; PPI 119, 120 (n = 2).

Head, including the eyes, broader than long. Clypeus lacking a median longitudinal carina; anterior clypeal margin rather straight. Frontal carinae reaching the level of the posterior margins of antennal insertions. Mesoscutum lacking distinct notauli and parapsidal furrows. Scuto-scutellar sulcus with nine narrow longitudinal ridges. Propodeum weakly tuberculate, lacking teeth or spines. Metapleural lobes with a blunt or somewhat rounded apex. Middle and hind tibiae without any spurs. Petiole node in profile low, nodiform, having an anterior face and a long anterior peduncle. Postpetiole in profile low and rounded dorsally, in dorsal view subrectangular and broader than long. Dorsum of head smooth and shining, but frontal area with a median longitudinal carina. Dorsal alitrunk generally smooth and shining, except for those marked sutures. Dorsal surfaces of petiole and postpetiole smooth and shining. Gaster unsculptured. All dorsal surfaces with abundant rather long hairs. Legs and scapes with numerous erect or suberect short hairs. Color blackish-brown. Wings infuscated.

Type Material

Wang (2003):

Lectotype worker, New Guinea: near Friedrich-Wilhelmshafen et Berlinhafen (Biro) (Museo Civico di Storia Naturale, Genoa), here designated, [examined].

Pristomyrmex mendanai Mann, 1919: 341. Two syntype workers, Solomon Is.: Santa Cruz Is., Graciosa Bay, 19.v.- 24 .xi.1916 (W. M. Mann) (Museum of Comparative Zoology, National Museum of Natural History) [examined].

References

  • Wang, M. 2003. A Monographic Revision of the Ant Genus Pristomyrmex (Hymenoptera:Formicidae). Bull. Mus. Comp. Zool. 157(6): 383-542 (page 499, Senior synonym of mendanai)