Proceratium foveolatum

One specimen was collected in lowland rainforest.

Identification
Differing from all the species of the stictum clade by the following combination of characters: gastral tergite I with a broad, strong angle on the curvature and by the head, mesosoma, petiole, postpetiole and gaster covered by foveae.

Distribution
Known from Malaysia (Sarawak) and Brunei Darussalam.

Distribution based on Regional Taxon Lists
Indo-Australian Region: Borneo, Brunei Darussalam, Indonesia, Malaysia.

Nomenclature

 *  foveolatum. Proceratium foveolatum De Andrade, in Baroni Urbani & De Andrade, 2003b: 78, figs. 48-50 (w.m.) BORNEO.

Worker
Head about as broad as long, narrower anteriorly than posteriorly. Vertex in full face view gently concave medially and in posterior view flat. Clypeus broad, convex, protruding anteriorly and surrounding the whole antennal insertions. Anteromedian margin of the clypeus with a notch. Frontal carinae very far from each other, strongly diverging posteriorly and not covering the antennal insertions. Frons deeply concave tnedially. Lateral expansions of the frontal carinae relatively broad and slightly raised. Genal carinae present, strongly marked, prolonging towards the hypostomal bridge and probably bounding an impressed gular area (not visible in the sole specimen available). A superficial sulcus between the genal carinae and the gular area. Eyes present, composed by a small but clear convex facet placed slightly below the mid-line of the head. Scapes thick, distally incrassate, and far short of the vertexal margin. First funicular joint as broad as long. Funicular joints 2-10 broader than long. Last funicular joint as long as the sum of joints 7-10. Mandibles with 3 denticles before the apical tooth. Palp formula probably 4,3.

Mesosoma slightly elongate, gently convex in side view. Promesonotal suture weakly impressed. Propodeal suture absent. Promesopleural and meso-metapleural sutures impressed on the ventral half only. Basal face of the propodeum slightly convex and declivous posteriorly. Declivous face of the propodeum gently concave and each side with a carinate sulcus. Propodeum with a pair of relatively long, broad spines between the basal and declivous faces. Propodeal lobes ventrally truncate and dorsally with a broad, round tooth protruding dorsally. Metapleurae impressed between the propodeal spines and propodeal lobes, each impression sheltering the propodeal spiracle.

Petiole about 1/5 longer than broad, in dorsal view subparallel in the anterior fifth and convex posteriorly. Anterior border of the petiole straight, with a thick margin slightly denticulate on each side. Ventral process of the petiole absent. Postpetiole slightly shorter than gastral tergite I (LT4), with the sides diverging backwards in dorsal view. Postpetiolar sternite anteromedially with a marked subtriangular projection. Center of the postpetiolar sternite slightly convex. Constriction between postpetiole and gastral segment I impressed. Gastral tergite I with a strong, broad angle on the curvature and narrowing distally after the curvature. Gastral sternite I very short medially. Remaining gastral tergites and sternites slightly curved ventrally.

Legs elongate but with stout tibiae, basitarsi, tarsi and tarsomeres. All tibiae with a pectinate spur. Spurs of fore legs with a basal spine. Fore basitarsi slightly 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 prclarsus. Pretarsal claws simple. Arolia small.

Sculpture. Head, mesosoma, petiole, postpetiole and gaster densely covered by deep and relatively large, slightly irregular foveae. Interspaces between foveae granulopunctate. Bottom of the foveae smooth. Scapes and legs strongly granulate.

Body covered by hairs of three main types: (1) short, dense, subdecumbent on the whole body, suberect and sparse on the funicular joints; (2) suberect, long, thick on the whole body, absent from the antennae; (3) shorter than hair type (1), dense, decumbent or appressed on the funicular joints only. In addition the funicular joints bear whitish, thick, appressed, short, sparse hairs and the scapes bear sparse hairs shorter than hair type (2).

Colour dark brown to black with lighter antennae and legs.

Measurements in mm and Indices: TL 5.52; HL 1.18; HW 1.18; EL 0.06; SL 0.86; WL 1.64; PeL 0.68; PeW 0.53; HFeL 1.18; HTiL 0.96; HBaL 0.70; LS4 0.22; LT4 0.96; CI 100.0; SI 72.0; IGR 0.23.

Male
(tentative attribution). Head broader than long. Vertex flat in full face and in posterior view. Vertexal margin medially concave and with a relatively broad carina. Clypeus anteromedially with a triangular projection. Frontal carinae thin, higher than in avioide and goliath, parallel and far from each other. Frontal area deeply concave anteriorly. Ocelli large. Compound eyes very large, strongly convex and largely on the anterior half of the head sides. Scapes not reaching the anterior ocellus. First funicular joint about 1/3 shorter than the second joint. Joints 2-10 longer than broad and slightly shorter than the subapical joint. Apical joint as long as the sum of joints 10-11. Mandibles short, with blades narrower than in stictum and deelemani, edentate, only with a pointed apical tooth. Palp formula probably 4,3.

Mesosoma robust. Pronotum and anterior third of mesonotum almost perpendicular to the posterior two thirds of the mesonotum. Posterior two thirds of mesonotum almost flat. Parapsidal furrows superficially marked. Scutellum as high as the mesonotum; posterior border of scutellum subround. Sides of the basal face of the propodeum with a broad, triangular tooth separated each other by a deep incision. Declivous face of propodeum weakly marginate on the sides. Propleurae with a deep sulcus. Metanotum with a strong median spine-like projection. PropodeaI lobes large and dorsally round.

Petiole about 1/3 longer than broad, with subparallel sides. Anterior border of the petiole truncate and with a small tooth on each side. Subpetiolar process absent. Postpetiole anteriorly slightly broader than the petiole; postpetiolar sides diverging posterioriy. Anterior border of the postpetiolar sternite carinate but not forming a triangular edge. Postpetiolar sternite with a posterior swelling.

Gastral tergite I making a strong, broad angle on the curvature and narrowing distally after the curvature. Gastral sternite I very short medially. Remaining gastral tergites and sternites curved ventrally.

Legs less stouter than in the worker. Arolia visible and small.

Fore wings of our type 2, hind wings of our type 1 as defined in the description of the genus.

Genitalia not dissected.

Sculpture. Head, mesosoma, petiole, postpetiole and gaster foveolategranulate, the foveae with irregular border, smaller on the frons and on the center of the pronotum, larger on the scutellum. Scapes and legs granulate, the granules more superficial than in the worker.

Pilosity as in the worker except for the hair type (2) which is longer on the scutellum and on the gaster.

Colour dark brown to black with funicular joints 2-12, coxae and femora lighter. Scapes, first funicular joint and remaining parts of the legs dark-orange ferrugineous.

Measurements in mm and Indices: TL 4.98; HL 0.84; HW 0.93; EL 0.41; SL 0.40; WL 1.72; PeL 0.60; Pew 0.38; I-IFeL 1.07; HTiL 0.82; HBaL 0.66; LS4 0.22; LT4 0.92; CI 111.0; SI 47.6; IGR 0.24.

Type Material
Holotype worker from Sarawak labelled: "Sarawak, 4th Div. G. Mulu Nat. Pk., RGS Expd Long Pala, lowl. rainf. leaf litter on log, 1.X.1977, B Bolton", in.

Etymology
Foveolatum is a neologism derived from the Latin fovea (= small hole) and refers to the integumental sculpture of this species.

References based on Global Ant Biodiversity Informatics

 * Baroni Urbani C., and M.L de Andrade. 2003. The ant genus Proceratium in the extant and fossil record (Hymenoptera: Formicidae). Museo Regionale di Scienze Naturali, Monografie 36: 1-480.
 * Pfeiffer M.; Mezger, D.; Hosoishi, S.; Bakhtiar, E. Y.; Kohout, R. J. 2011. The Formicidae of Borneo (Insecta: Hymenoptera): a preliminary species list. Asian Myrmecology 4:9-58