De Andrade, 2003
The types were collected in rainforest.
A member of the silaceum clade, resembling Proceratium australe and Proceratium caledonicum but differing from australe, in the worker, by the narrower frontal carinae, and from caledonicum, in the worker, by the body with stronger sculpture and by the erect hairs shorter, and from both species, by the broader petiole and by the mesosoma more convex in profile.
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Distribution based on Regional Taxon Lists
Distribution based on AntMaps
Distribution based on AntWeb specimens
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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.
- pumilio. Proceratium pumilio De Andrade, in Baroni Urbani & De Andrade, 2003b: 350, fig. 138 (w.) AUSTRALIA.
- Holotype, worker, Mt. Demi, 7km SW Mossman, Queensland, 1000m, Australia, Australian National Insect Collection; , Rainforest, sieved litter. , 29 October 1983, Yeates,D.K. & Thompson,G.I., ANIC32-017671, QM Berlesate No. 604,
Head slightly longer than broad and with the sides wealtly diverging posteriorly. Vertex in full face view convex and gently incised medially. Clypeus reduced and as long as the antennal sockets. Anterior border of the clypeus truncate. Frontal carinae not very far from each other, slightly covering the antennal insertions. Lateral expansions of the frontal carinae narrow, little raised, gently diverging on the two anterior thirds, shortly converging, subparallel and carinate only on the last third. Frontal area gently concave and with a central longitudinal carina starting from the posterior border of the concavity and prolonging posteriorly. Head anterolaterally with a short longitudinal carina. Genal carinae marked, each carina corresponding to the external border of a deep sulcus. Eyes composed by a small agglomeration of ommatidia and on the middle of the head sides. First funicular joint about as long as broad. Funicular joints 2-10 broader than long. Last funicular joint as long as the sum of joints 6-10. Scapes short of the vertexal margin and gently thickening apically. Masticatory margin of the mandibles with 5 denticles before the pointed apical tooth. Palp formula 2,2.
Mesosoma convex and slightly shorter than maximum head length (mandibles inc1uded)in profile. Pronotal and propodeal sutures absent. Basal face of the propodeum gently declivous posteriorly. Declivous face of the propodeum sloping posteriorly. Area between the basal and declivous faces of the propodeum weakly concave medially and with a minute, carinate denticle on each side. Declivous face superficially marginate laterally. Propodeal spiracle round and above mid height in lateral view.
Petiole subrectangular and nanow. Petiolar width more than 1 and ½ broader than long. Anterior border of the petiole straight and anterolaterally weakly carinate. Ventral process of the petiole small and triangular. Postpetiolar sternite anteromedially with a marked subround projection, gently convex in side view. Constriction between postpetiole and gaster impressed. Gastral tergite I about 1/3 longer than the postpetiole and convex on the curvature. Remaining gastral tergites and sternites curved ventrally.
Legs moderately short. All tibiae with a pectinate spur. Spurs of fore legs without basal spine. Fore basitarsi longer than the mid ones. Hind basitarsi about 1/4 shorter than hind tibiae. Second tarsomere of hind legs about as long as the pretarsus. Pretarsal claws simple. Arolia absent.
Sculpture. Head dorsum, mesosoma, petiole and postpetiole punctate, the punctures denser and more impressed on the head, very superficial and resembling minute foveae on the mesosoma. Head sides with dense, small, piligerous foveae resembling reticulation and few, slightly longitudinal rugosities. Gaster smooth and with minute piligerous punctures, the punctures denser and larger on the sides. Legs punctate.
Body covered by hairs of three main types: (1) short, dense, subdecumbent on the whole body, suberect and sparse on the funicular joints; (2) longer than type (1), erect on the whole body, slightly shorter on the scapes, absent on the funiculi; (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. Light brown with lighter antennae and legs.
Measurements in mm and Indices: TL 2.55-2.63; HL 0.58-0.60; HW 0.55-0.56; EL 0.04; SL 0.39-0.41; WL 0.69-0.71; PeL 0.18-0.19; PeW 0.33; HFeL 0.41; HTiL 0.32-0.34; HBaL 0.24-0.26; LS4 0.27-0.29; LT4 0.57-0.58; CI 93.3-94.8; SI 67.2-68.3; IGR 0.47-0.50.
Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.
From the Latin pumilio (Lucretius, Seneca) = dwarf, pygmy, referred to the small size of this species.
- 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 350, fig. 138 worker described)