Proceratium colombicum

Identification
A member of the micrommatum clade. Differing from Proceratium brasiliense and Proceratium catio, in the worker, by the following set of characters: head, mesosoma, petiole and postpetiole covered by dense granulation instead of granulate-rugulose foveolate, and first gastral tergite entirely densely granulate instead of densely granulate after the curvature only. (Baroni Urbani and de Andrade 2003)

Distribution
This taxon was described, and is only known, from Colombia.

Nomenclature

 *  colombicum. Proceratium colombicum De Andrade, in Baroni Urbani & De Andrade, 2003b: 131, figs. 60, 61 (w.) COLOMBIA.

Worker
Head longer than broad; its sides slightly narrower anteriorly than posteriorly. Vertex in full face view convex. Clypeus recognizable as a small triangular or subtriangular tooth between the antennal sockets. Frontal carinae close to each other, not covering the antennal insertions. Frontal area behind the frontal carinae weakly convex. Lateral expansions of the frontal carinae relatively narrow, raised and diverging posteriorly. Genal carinae strongly marked. Sulcus between the genal carinae and the gular area impressed. Eyes present, composed by a clearly convex facet slightly below the midline of the head. Ocelli absent. Scapes thicker in the distal half and far short of the vertexal margin. First funicular joint 113 longer than broad. Funicular joints 2-10 broader than long. Last funicular joint as long as the sun1 of joints 7-10. Mandibles with 3 denticles before the apical tooth. Palp formula 3,2.

Mesosoma slightly elongate. Promesopleural and mesometapleural sutures impressed on the ventral half only. Basal face of the propodeum with a semitransparent tumulus medially; area behind the propodeal tumulus short, and resembling a transversal sulcus, the sulcus more concave medially and postero-laterally carinate. Declivous face of the propodeum flat, its sides crenulate and sub-convex close to the propodeal lobes. Propodeal lobes truncate. Propodeal spiracles tumuliform.

Petiole slightly longer than broad, with the sides subparallel in the anterior third and convex posteriorly in dorsal view. Anterior border of the petiole straight, carinate and slightly denticulate on each side. Ventral process of the petiole very small and subtriangular. Postpetiole slightly shorter than 1/2 of the length of the gastral tergite I (LT4 with convex sides), in dorsal view. Postpetiolar dorsum with a median, short tumulus close to the posterior border. Postpetiolar sternite anteromedially with a marked subround projection. Posterior half of the postpetiolar sternite slightly convex. Constriction between postpetiole and gastral segment I strongly impressed. Gastral tergite I weakly inflate dorsally and with broad, round curvature. Gastral sternite I very short medially, carinate and protruding anteriorly on the sides. Remaining gastral tergites and sternites curved ventrally.

Legs slightly elongate. Mid tibiae without 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 mid and hind legs longer than third and fourth tarsomeres, and shorter than pretarsus. Pretarsal claws simple. Arolia small.

Sculpture. Head, mesosoma, petiole, postpetiole and gaster strongly granulate. Legs granulo-punctate.

Body covered by hairs of three main types: (1) short, dense, subdecumbent on the whole body, very dense on the tumulus of the basal face of the propodeum, sparse and erect on the funicular joints; (2) long, erect or suberect and sparse on the whole body, absent from the tumulus of the basal face of the propodeum and on the antennae, slightly longer on the petiole, postpetiole and on the gaster; (3) shorter than hair type (1), dense, subdecumbent or appressed on the funicular joints only. In addition the funicular joints bear whitish, thick, appressed, short, sparse hairs, and the scapes with sparse hairs similar to type (2) but shorter.

Colour light ferrugineous-brown with slightly lighter antennae and legs.

Measurements in mm and Indices: TL 2.82; HL 0.65; HW 0.57; EL 0.05; SL 0.42; WL 0.80; PeL 0.29; PeW 0.25; HFeL 0.47; HTiL 0.39; HBaL 0.28; LS4 0.14; LT4 0.64; CI 87.7; S164.6; IGR 0.22.

Type Material
Holotype worker (unique) from Colombia labelled: "Narino, Orito, Territorio Kofan, 00°30' N 77°13' W, 1000 m, 25.IX 1998, E. L. Gonzales", rn.

Etymology
“Colombicum” is a neologism indicating the provenance of this species from Colombia.