Proceratium microsculptum

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

Proceratium microsculptum P casent0902415.jpg

Proceratium microsculptum D casent0902415.jpg

Specimen Label

Nothing is known about the biology of Proceratium microsculptum.

Identification

A member of the microsculptum clade. Differing from all the other species of the genus, in the worker and gyne, by the following combination of characters: frontal carinae posteriorly contiguous, genal carinae strongly marked, second gastral tergite entirely foveolate, propodeal suture dorasally impressed and declivous face of the propodeum with lamellae.

Keys including this Species

Distribution

Malaysia (Sabah).

Distribution based on Regional Taxon Lists

Indo-Australian Region: Borneo (type locality), Indonesia, Malaysia.


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.

  • microsculptum. Proceratium microsculptum De Andrade, in Baroni Urbani & De Andrade, 2003b: 199, fig. 84 (w.q.) BORNEO.

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

Description

Worker

Head slightly longer than broad, its sides gently diverging posteriorly. Vertex in full face view almost straight. Clypeus anteriorly protruding, lamellaceous, relatively broad, subconvex and completely surrounding the antennal sockets. Anterior border of the clypeus subtruncate and crenulate. Frontal carinae fused posteriorly, not covering the antennal insertions. Lateral expansions of the frontal carinae narrow and raised. Genal carinae strongly marked, lamellaceous; each carina corresponding to the external border of a deep sulcus. Eyes absent. First funicular joint 1/2 longer than broad. Funicular joints 2-10 slightly broader than long. Last funicular joint about as long as the sum of joints 7-10. Scapes short of the vertexal margin and gently thickening apically. Masticatory margin of the mandibles with 2-3 denticles before the pointed apical tooth. Palp formula 4,3.

Mesosoma gently convex and slightly longer than the maximum head length (mandibles included) in profile. Propodeal suture superficially impressed. Basal face of the propodeum declivous posteriorly. Declivous face of the propodeum flat. Basal and declivous faces of the propodeum separated dorsally by a well marked, diverging carina, the carina connected to a subround, broad tooth on each side. Each side of the declivous face of the propodeum with a broad lamella, broader and round posteriorly. Propodeal spiracle round and over the mid height in lateral view.

Petiole strongly convex in profile, with the sides parallel on the anterior sixth and strongly convex posteriorly in dorsal view. Anterior border of the petiole concave and laterally carinate, the carina denticulate each side. Ventral process of the petiole triangular and pointed. Postpetiole anteriorly slightly broader than the petiole; its sides diverging and gently convex posteriorly. Postpetiolar sternite anteromedially with a marked subtriangular projection, almost straight in side view. Constriction between postpetiole and gaster impressed. Gastral tergite I slightly shorter than twice than the postpetiole, weakly angulate on the curvature. Remaining gastral tergites and sternites curved ventrally.

Legs slender and slightly elongate. All tibiae with a pectinate spur. Spurs of fore legs without basal spine. Fore basitarsi longer than the mid ones. Hind basitarsi about 1/5 shorter than hind tibiae. Second tarsomere of hind legs subequal in size to the pretarsus. Pretarsal claws simple. Arolia present.

Sculpture. Head, mesosoma and petiole granulopunctate, irregularly rugulose-foveolate; the foveae very sparse on the head. Postpetiole punctate-foveolate. Gaster smooth, minutely punctate and covered by large foveae. Legs punctate.

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 (1), erect on the whole body, slightly shorter on the scapes; (3) shorter than hair type (1), dense and decumbent on the funicular joints only. In addition the funicular joints bear whitish, thick, appressed, sparse hairs.

Colour. Ferrugineous brown.

Measurements in mm and Indices: TL 3.60; HL 0.84-0.85; HW 0.76-0.78; EL absent; SL 0.61; WL 1.03-1.04; PeL 0.33; PeW 0.32-0.33; HFeL 0.68; NTiL 0.55-0.56; HBaL 0.43; LS4 0.19-0.20; LT4 0.90-0.91; CI 90.5-91.8; ST 71.8-72.6; IGR 0.21-0.22.

Queen

Differing from the worker in the following details: eyes large, their maximum diameter 1/5 of the head length and composed of many facets with interommatidial pilosity. Ocelli well developed.

Mesosoma robust and convex in profile. Parapsidal furrows weakly marked. Scutellum with the sides converging posteriorly and with the posterior border subtruncate. Metanotum with a lamellaceous tooth.

Measurements in mm and Indices: TL 4.1 1; NL 0.87; HW 0.81; EL 0.17; SL 0.65; WL 1.24; PeL 0.37; PeW 0.36; HFeL 0.77; HTiL 0.60; HBaL 0.48; LS4 0.20; LT4 1.06; CI 93.1 ; SI 74.7; IGR 0.19.

Type Material

Holotype worker from Sabah labelled: "SABAH, Gn. Silam, 810 m, 1983, R. Leakey"; in The Natural History Museum; paratypes: 2 workers and 1 gyne, same data and collection as the holotype.

Etymology

"Microsculptum" is a barbarism alluding to the fine integumental structure of this species.

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 199, fig. 84 worker , queen described)