Pristomyrmex picteti

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Pristomyrmex picteti
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Myrmicinae
Tribe: Crematogastrini
Genus: Pristomyrmex
Species: P. picteti
Binomial name
Pristomyrmex picteti
Emery, 1893

Pristomyrmex picteti casent0281795 p 1 high.jpg

Pristomyrmex picteti casent0281795 d 1 high.jpg

Specimen Labels

Synonyms

This species occurs in rainforest, nesting in rotten logs. It has been collected on the ground, on rotten wood, and under loose bark of a log.

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 fairly long, about 1.3 to 1.5 X the distance between their bases, not strongly upcurved at their apices.

Pristomyrmex picteti occurs in Papua New Guinea, Borneo, Sabah, Brunei, Malaya, Singapore, and the Philippines. It is closely related to several other species of the umbripennis group. A discussion regarding the relationship between P. picteti and Pristomyrmex fuscipennis is provided under P. fuscipennis. Characters separating P. picteti from Pristomyrmex umbripennis are listed under P. umbripennis. The workers of P. picteti differ from those of Pristomyrmex pollux as follows: P. picteti - Propodeal spines relatively short, not strongly upcurved at their apices, Smaller species with HL 1.04-1.36, HW 1.02-1.40 and SL 0.92-1.26. Dorsum of head with scattered foveolate punctures; space between foveolae often smooth. Anterior margin of the median portion of clypeus usually with fewer than seven denticles. P. pollux - Propodeal spines relatively long, strongly upcurved at their apices. Larger species with HL 1.42-1.54, HW l.42-1.58, and SL 1.40-1.52. Dorsum of head with foveolate-reticulate sculpture. Anterior margin of the median portion of clypeus usually with seven denticles.

A member of the Umbripennis species group

Keys including this Species

Distribution

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo, Indonesia (type locality), Malaysia, Malaysia, New Guinea, Philippines, Singapore.

Distribution based on specimens

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The above specimen data are provided by AntWeb. Please see Pristomyrmex picteti 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.

  • picteti. Pristomyrmex picteti Emery, 1893e: 190 (w.) INDONESIA (Sumatra). Forel, 1912d: 107 (q.m.). Senior synonym of tingiana: Wang, M. 2003: 518.
  • tingiana. Pristomyrmex picteti var. tingiana Stitz, 1925: 120, fig. 4 (w.) PHILIPPINES. Junior synonym of picteti: Wang, M. 2003: 518.

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 4.10-.5.84, HL 1.04-1.36, HW 1.02-1.40, CI 96-108, SL 0.92-1.26, SI 85-97, EL 0.05-0.09, PW 0.68-0.88, AL 1.12-1.58, PPW 0.30-0.41, PPL 0.27-0.36, PPI 100-120 (n = 40).

Mandibles rather smooth or sometimes with a few longitudinal rugae. Basal margin of mandible with a broad-based, subtriangular, Short prominence or a somewhat curved lobe. Clypeus smooth and shining, except for a median longitudinal carina that usually crosses the entire clypeus but sometimes does not reach the posterior clypeal margin. Anterior margin of the median portion of clypeus (not including the margins in front of the antennal fossae) with a median denticle and two (sometimes three) lateral denticles on each side. Ventral surface of clypeus with a coarse, transverse, long carina. Palp formula 1,3. Frontal carinae usually beyond the eyes. Antennal scrobes indistinct. Frontal lobes present, partially covering the condylar bulbs of holding antennal scapes. Antennal scapes, when lying on the dorsal head, just reaching or slightly beyond the occipital margin. Lamella, encircling the base of antennal scape, usually with a broad and deep notch on the center of the dorsal surface, but in several specimens (from Palawan I., Philippines), this lamella is entire, without a notch. Eyes very small, usually with three, at most four, ommatidia in the longest row. Occipital margin straight or very feebly concave in full-face view. Alitrunk in profile with a convex dorsum. Pronotum unarmed. Propodeum with a pair of fairly long spines, ca. 1.3 to 1.5 X the distance between their bases; sometimes the spines are weakly upcurved at their apices. Metapleural lobes rounded or somewhat truncated. Petiole node in profile slightly longer than high, with a fairly long anterior peduncle; its anterodorsal angle is usually on approximately the same level as the posterodorsal, but sometimes the former is slightly higher than the latter. Subpetiole with a narrow, semitranslucent lamella. Postpetiole in profile higher than long, rounded dorsally, in dorsal view broadening from front to back. Dorsal and ventral surfaces of head, dorsum of alitrunk, as well as the sides of pronotum with numerous foveolate punctures; space between foveolae often smooth. Antennal scapes smooth, or with one to two longitudinal rugae along their margins. Petiole smooth and shining, except for a longitudinal ruga on each side. Postpetiole and gaster smooth and shining. Dorsal surfaces of head and alitrunk with numerous erect or suberect short hairs. Two or more pairs of hairs present on the dorsal surfaces of petiole node and postpetiole, respectively. A few of forward-projecting long hairs present near the anterior clypeal margin. Scapes and tibiae with numerous erect or suberect short hairs. First gastral tergite lacking erect or suberect hairs. Color reddish-brown.

Queen

Wang (2003) - TL 6.20-7.02, HL l.32-l.64, HW 1.42-l.69, CI 103-113, SL l.21-l.56, SI 85-92, EL 0.29-0.34, PW l.14-l.42, AL l.74-2.14, PPW 0.41-0.52, PPL 0.36-0.42, PPI 110-125 (n = 13).

General shape with normal caste differences from the con specific worker; eyes much larger, usually containing more than 17 ommatidia in the longest row; other characters similar to worker.

Male

Wang (2003) - TL 4.46-5.28, HL 0.68-0.78, HW 0.69-0.80, CI 95-108, SL 0.30-0.42, SI 40-56, HWE 0.85-0.94, EL 0.35-0.39, PW 0.92-l.14; AL l.44-l.78, PPW 0.30-0.38, PPL 0.28-0.34, PPI 10.3-114 (n = 5).

Head in full-face view, including the eyes, broader than long. Clypeus convex, lacking a median longitudinal carina. Palp formula 1,3. Frontal carinae distinct, extending to the level of the posterior margins of antennal insertions. Maximum diameter of the median ocellus 0.10 to 0.12. Scapes longer than the other antennal segments, except for the apical ones. On the mesoscutum, notauli rather wide, forming a V shape, separated into several cells by narrow transverse ridges; parapsidal furrows absent. Scuto-scutellar sulcus wide, usually with five to six narrow longitudinal ridges. Propodeum armed with a pair of robust, triangular short spines. Metapleural lobes subtriangular. Middle and hind tibiae without any spurs. Petiole node in profile low, slightly longer than high, with a fairly long anterior p eduncle. Postpetiole in profile rounded dorsally, in dorsal view somewhat transversely rectangular and slightly broader than long. Dorsum of head with some small punctures, varying I from scatte red and shallow to dense and somewhat coarsely incised. Pronotum with dense foveolate punctures. Mesonotum with punctures, varying from a few scattered to numerous and from feeble, small to rather large. Propodeum rugulose. Sides of petiole with a few longitudinal rugae as well as some foveolate punctures between them. Sides of postpetiole with some shallow foveolate punctures. Gaster unsculptured. All dorsal surfaces with numerous blackish-brown long hairs; sometimes hairs somewhat stiff. Color blackish-brown; wings dusky.

Type Material

Wang (2003):

Lectotype worker, Sumatra: Deli (Bedot) (Museo Civico di Storia Naturale, Genoa), here designated, [examined].

Pristomyrmex picteti tingiana Syntype workers, Philippines: N. Palawan, Binaluan, xi- xii 1913 (C. Boettcher) (Berlin Museum für Naturkunde der Humboldt-Universität, Museum of Comparative Zoology) [examined].

References

  • Emery, C. 1893g. Formicides de l'Archipel Malais. Rev. Suisse Zool. 1: 187-229 (page 190, worker described)
  • Forel, A. 1912e. Ameisen aus Java beobachtet und gesammelt von Edward Jacobson. III. Theil. Notes Leyden Mus. 34: 97-112 (page 107, queen, male described)
  • Wang, M. 2003. A Monographic Revision of the Ant Genus Pristomyrmex (Hymenoptera:Formicidae). Bull. Mus. Comp. Zool. 157(6): 383-542 (page 518, figs. 247-250, 268, 279 worker, queen, male described, Senior synonym of picteti var. tingiana)