Proceratium sulawense

Identification
A member of the silaceum clade and resembling Proceratium dusun, but differing from it, in the worker, by the broader frontal carinae and by the CI > 101.5 instead of < 97.

Distribution
Indonesia (Sulawesi) and Malaysia (Sarawak)

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

Nomenclature

 *  sulawense. Proceratium sulawense De Andrade, in Baroni Urbani & De Andrade, 2003b: 392, fig. 151, 152 (w.q.) INDONESIA (Sulawesi).

Worker
Head as broad as long or slightly broader than long and with the sides gently convex. Vertex in full face view weakly convex. Clypeus reduced and as long as the antennal sockets. Anterior border of the clypeus truncate. Frontal carinae far from each other, slightly covering the antennal insertions. Lateral expansions of the frontal carinae broad, little raised, diverging on the two anterior fourths, converging on the third fourth, subparallel and carinate only on the last fourth. Frontal area gently concave on the three anterior fourths and with a central, thick longitudinal carina starting from the last fourth and prolonging posteriorly. Head anterolaterally with a short, thin, longitudinal carina. Genal carinae marked, each carina corresponding to the external border of a deep sulcus. Eyes visible as by a dark dot below the integument, small and on the middle of the head sides. First funicular joint slightly longer than broad. Funicular joints 2-10 broader than long. Last funicular joint as long as the sum ol joints 6-10. Scapes short of the vertexal margin and gently thickening apically. Masticatory margin of the inandibles with 8 denticles before the pointed apical tooth. Palp formula 2,2.

Mesosoma in side view gently convex and about as long as the maximum head length (mandibles included). Pronotal and propodeal sutures absent. Basal face of the propodeum declivous posteriorly. Area between the basal and declivous Faces of the propodeum concave, dorsally carinate and laterally denticulate. Declivous face of the propodeum gently sloping posteriorly. Sides of the declivous face carinate. Propodeal spiracle round and above mid height in lateral view.

Petiole subrectangular and slightly compressed. Anterior border of the petiole straight and anterolaterally carinate. Ventral process of the petiole large, stout and triangular. Postpetiole in dorsal view with sides diverging on the anterior half and gently convex on the posterior half. Postpetiolar sternite anteromedially with a marked subtriangular projection, gently convex posteriorly 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 lergites and sternites curved ventrally.

Legs relatively 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 shorter than pretarsus. Pretarsal claws simple. Arolia absent.

Sculpture. Head dorsum rugosopunctate, the rugosities thicker and slightly longitudinal on the sides. Mesosoma, petiole, postpetiole, anterior and sides of the first gastral tergite minutely granulopunctate. Remaining gastral tergite smooth and with minute piligerous punctures. Legs punctate. Body covered by hairs of three types: (1) short, dense, suberect or subdecumbent on the whole body, 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. Dark ferrugineous with lighter antennae and legs.

Measurements in mm and Indices: TL 2.90; HL 0.65; HW 0.66; EL 0.04; SL 0.42; WL 0.80; PeL 0.21; PeW 0.31; HFeL 0.47; HTiL 0.38; HBaL 0.29; LS4 0.31; LT4 0.62; CI 101.5; ST 64.6; IGR 0.50.

Queen
(tentative attribution). Differing from the worker in the following details: eyes large, about 1/4 of the head length, composed by many facets and with ocular pilosity. Ocelli well developed.

Mesosoma robust and convex in side view. Parapsidal furrows marked. Scutellum with the sides converging posteriorly and with the posterior border round. Dorsum of the scutellum with a thick, longitudinal ruga prolonging up to the posterior half of the mesonotum. Metanotum with a small Iamellaceous tooth. Basal face of the propodeum medially concave. Area between basal and declivous faces of the propodeum carinate and with a salient tooth on each side.

Measurements in mm and Indices: TL 4.32-4.34; HL 0.89-0.91; HW 0.94-0.95; EL 0.23-0.26; SL 0.59-0.60; WL 1.32-1.36; PeL 0.27-0.29; PeW 0.43-0.45; HFeL 0.75-0.76; HTiL 0.58-0.60; HBaL 0.50; LS4 0.43-0.47; LT4 0.88-0.92; CI 104.4- 105.6; SI 65.9-66.3; IGR 0.49-0.51.

Type Material
Holotype worker from Sulawesi labelled: "Indonesia: Sulawesi Utara, Danau Mooat, 1200 m, nr Kotamobagu, 13.7X.1985", in.

Etymology
"Sulawense" is a neologism indicating the provenance of the species from Sulawesi.