| Proceratium confinium|
De Andrade, 2003
Nothing is known about the biology of Proceratium confinium.
A member of the pergandei clade. Proceratium confinium resembles Proceratium californicum in general morphology. Both species have impressed propodeal suture, a unique character for some members of the pergandei clade but appearing also in two other species (Proceratium toschii and Proceratium microsculptum) belonging to different clades. Differing from californicum, in the worker, by the antennal socket strongly surpassing the anterolateral clypeal border instead of simply behind the anterolateral clypeal border, by the sculpture on the head, mesosoma and petiole more marked and by the presence of long, suberect hairs on the antennae, head, mesosoma, petiole, postpetiole and legs. (Baroni Urbani and de Andrade 2003)
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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.
The following information is derived from Barry Bolton's New General Catalogue, a catalogue of the world's ants.
- confinium. Proceratium confinium De Andrade, in Baroni Urbani & De Andrade, 2003b: 248, fig. 103 (w.) PAKISTAN.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
Head longer than broad, with subparallel sides, gently converging posteriorly on the posterior fourth. Vertex in full face view flat. Anteromedian part of the clypeus small, triangular, protruding anteriorly slightly more than the antenna1 socket. Antennal socket strongly protruding anteriorly and surpassing the anterolateral clypeal margin. Frontal carinae almost touching each other, narrowly separated posteriorly. Lateral expansions of the frontal carinae extremely narrow and slightly higher medially. Head anterolaterally with a short, superficially marked, longitudinal carina. Genal carina absent. Gular area not impressed. Eyes absent: without trace even of pigmented cuticular spot. First funicular joint about half longer than broad. Funicular joints 2-10 as broad as long to slightly longer than broad. Last funicular joint slightly shorter than the sum of the joints 7-10. Scapes almost reaching the vertexal border. Masticatory margin of the mandibles with 3 denticles before the pointed apical tooth. Palp formula apparently 3,2.
Mesosoma robust, longer than the head length (mandibles included). Pronotum and mesonotum convex in profile. Propodeal suture deeply impressed. Basal face of the propodeum slightly declivous posteriorly. The area between the basal and declivous faces gently concave and minutely denticulate on each side. Declivous face flat; its sides marginate. Propodeal spiracle round and above Inid height in lateral view. Propodeal lobes round and with a lamellaceous border.
Petiole convex in side view and with the sides diverging on the anterior fourth and strongly convex posteriorly in dorsal view. Anterior border of the petiole concave and carinate, the carina denticulate on each side. Ventral process of the petiole lamelliform, broad and triangular. Postpetiole half long as gastral tergite I; its anterior face high and broader than the petiole; its sides gently convex. Postpetiolar sternite anteromedially with a broadly marked subtriangular projection protruding anteriorly. Posterior half of the postpetiolar sternite flat. Constriction between postpetiole and first gastral segment impressed. Gastral tergite I strongly convex on the curvature. Remaining gastral tergites and sternites originating just after the curvature.
Legs slender but not very elongate. All tibiae with a pectinate spur. Spurs of fore legs with basal spine. Fore basitarsi as long as the mid ones. Hind basitarsi about 1/6 shorter than hind tibiae. Second tarsomere of hind leg longer than the pretarsus. Pretarsal claws simple. Arolia present.
Sculpture. Head granulopunctate. Mesosoma and petiole granulate. Postpetiole superficially shining, very sparsely granulate. Legs minutely punctate. Gaster superficially shining and covered by minute, piligerous impressions.
Body covered by hairs of three main types: (1) short, dense, decumbent or appressed on the whole body, sparse and suberect on the funicular joints; (2) longer than type (1) suberect on the whole body, absent on the funiculi; (3) shorter than hair type (1), dense and appressed on the funicular joints only. In addition the funicular joints bear whitish, thick, appressed, short, sparse hairs, and the scapes with sparse hairs shorter than hair type (2).
Colour light brown.
Measurements in mm and Indices: TL 3.29; HL 0.79; HW 0.63; SL 0.66; WL 0.95; PeL 0.30; PeW 0.26; HFeL 0.67; HTiL 0.63; HBaL 0.52; LS4 0.30; LT4 0.80; CI 79.7; SI 83.5; IGR 0.37.
Holotype worker from Malkandi, Paklstan labelled "Pakist. Swat, Malkandi 36, 1500 m, 2.VI.83, Lobl-Besuchet", in Musee d'Histoire Naturelle Genève.
From the Latin confines, referred to its provenance from the Frontier Territories.
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 248, fig. 103 worker described)