Proceratium malesianum

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Proceratium malesianum
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hymenoptera
Family: Formicidae
Subfamily: Proceratiinae
Tribe: Proceratiini
Genus: Proceratium
Species: P. malesianum
Binomial name
Proceratium malesianum
De Andrade, 2003

Proceratium malesianum P casent0281859.jpg

Proceratium malesianum D casent0281859.jpg

Specimen Label

Nothing is known about the biology of Proceratium malesianum.

Identification

A member of the itoi clade. Sister species of Proceratium bhutanense with which it shares synapoanorphically the palp formula 3,2 and the presence of a propodeal lamella. The two species are easily distinguished by the erect hairs present in malesianum and absent in bhutanense. (Baroni Urbani and de Andrade 2003)

Keys including this Species

Distribution

Malaysia: Pahang.

Distribution based on Regional Taxon Lists

Indo-Australian Region: Malaysia (type locality).

Distribution based on AntMaps

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Distribution based on AntWeb specimens

Check data from AntWeb

Biology

Very little is known about the biology of Proceratium ants. They nest in soil, rotten wood, under deep-set stones and, in a few cases, tree branches. For many species the nest consists of small rounded chambers hollowed out of soft rotten wood or in the soil. Toward the cooler limits of the range, particularly in North America, nests and foraging workers are found under deep set rocks instead of in rotten wood. The nest site is usually in forest shade, in old moist gardens, or similar habitats that are constantly moist. Some species of known to be egg predators of arthropods, especially of spiders.

Most Proceratium are relatively rare but this is not the full explanation for why they are not commonly collected. Colonies of most species are small. Based on anectdotal natural history information from a few species, it was once thought that most Proceratium would likely be found to have mature colonies that contain somewhere between 10 - 50 workers. Yet nests with more than 50, and in some cases up to 200, workers have been been reported. Besides small colonies, these ants also do not appear to forage in places where they are readily encountered.

Males and females are though to be produced in small numbers but we generally do not have enough data for colonies of any species to know what might be typical. Reproductive flights have been observered toward the end of the summer in some northern temperate areas. In these regions the nuptial flight occurs during the last half of August. Both sexes climb some distance from the nest entrance before taking flight. Workers too issue from the nest during the nuptial flight, as is often the case with otherwise cryptobiotic ants.

Castes

Nomenclature

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

  • malesianum. Proceratium malesianum De Andrade, in Baroni Urbani & De Andrade, 2003b: 275, fig. 115 (w.) WEST MALAYSIA.

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

Description

Worker

Head longer than broad, its sides subparallel. Vertex in full face gently convex. Clypeus medially reduced, triangular, between and slightly longer than the antennal sockets. Clypeal dorsum with longitudinal carina. Antenna1 socket with broad torulus. Frontal carinae slightly far from each other, partially covering the antennal insertions. Frontal area behind the frontal carinae convex. Lateral expansions of the frontal carinae relatively narrow, raised, and diverging. Genal carinae marked. Eyes small, reduced to a dark dot below the integument, placed on the midline of the head. First funicular joint subeq~lalin size. Funicular joints 2-10 much broader than long. Last funicular joint about as long as the sum of joints 6-10. Scapes much short of the vertexal margin and gently thickening apically. Masticatory margin of the mandibles with 3 denticles before the pointed apical tooth. Palp formula 3,2.

Mesosoma slightly longer than the maximum head length (mandibles included). Promesopleural and meso-metapleural sutures impressed ventrally only. Basal face of the propodeum weakly declivous. Declivous face of the propodeum gently concave anteriorly. Basal and declivous faces of the propodeum separate laterally by a weakly carinate angle. Sides of the declivous face ofthe propodeum with a broad lamella. Propodeal spiracle round and placed above mid height in lateral view.

Petiole strongly convex in profile, with the sides diverging and strongly convex posteriorly in dorsal view. Anterior border of the petiole deeply concave and carinate, the carina strongly denticulate on each side. Ventral process of the petiole with 2-4 small, triangular denticles. Postpetiole anteriorly broader than the petiole; its sides diverging and gently convex posteriorly. Postpeliolar sternite anteromedially with a marked subtriangular projection. Postpetiolar sternite straight in profile. Constriction between postpetiole and first gastral segment impressed. Gastral tergite I strongly convex on the curvature. Remaining gastral tergites and sternites curved ventrally.

Legs slender but not very elongate. All tibiae with a pectinate spur. Spurs of fore legs without basal spine. Fore basitarsi longer than the mid ones. Hind basitarsi about 113 shorter than hind tibiae. Second tarsomere of hind legs subequal to the fourth. Pretarsal claws simple. Arolia present.

Sculpture. Head, mesosoma, petiole and postpetiole granulate. First gastral tergite smooth and covered by piligeroirs punctures; its sides and the posterior border with additional granulation. Legs granulate, the granules less marked than in the other body parts.

Body covered by hairs of three main types: (1) short, dense, subdecumbent on the whole body, sparse and suberect on the funicular joints; (2) longer than type (I), sparse and s~tberecot n the whole body, slightly shorter on the scapes, absent on the funiculi; (3) shorter than hair type (I), dense and decumbent on the funicular joints only. In addition the funicular joints bear whitish, thick, appressed, short, sparse hairs.

Colour. Dark brown.

Measurements in mm and Indices: TL 2.57-3.24; HL 0.61-0.75; HW 0.53-0.65; EL 0.03-0.04; SL 0.36-0.45; WL 0.71-0.90; PeL 0.26-0.32; PeW 0.24-0.29; HFeL 0.43-0.55; MTiL 0.35-0.49; HBaL 0.21-0.31; LS4 0.20- 0.27; LT4 0.57-0.72; CI 87.0; SI 59.0-60.0; IGR 0.35-0.38.

Type Material

Holotype worker from West Malaysia labelled: "W. Malaysia. Pahang, Ringlet. 1250 m, ravine # 20, Lob1 & Calame, 26.3.93", in Musee d'Histoire Naturelle Genève

Etymology

"malesianum" is a neologism indicating the provenance of this species from Malaysia.

References

  • Baroni Urbani, C., de Andrade, M.L. 2003. The ant genus Proceratium in the extant and fossil record (Hymenoptera: Formicidae). Museo Regionale di Scienze Naturali, Monografie, 36, 1–492. (page 275, fig. 115 worker described)