Proceratium snellingi

Identification
A member of the silaceum clade. Proceratium snellingi is a relatively small species. It shares with Proceratium angulinode, Proceratium striativenter, Proceratium banjaranense, Proceratium dusun and Proceratium papuanum the hind basitarsi with at least one hair longer than 1/2 of the hind basitarsi. Among these five species, snellingi resembles particularly papuanum, but snellingi differs from it, in the worker, by its small size coupled with a broad head (TL ≤ 2.29 mm and CI ≥ 100), a more sculptured body and a narrower frontal carinae. (Baroni Urbani and de Andrade 2003)

Key to Oceanian Proceratium Species

Distribution
Papua New Guinea

Distribution based on Regional Taxon Lists
Indo-Australian Region: New Guinea.

Nomenclature

 *  snellingi. Proceratium snellingi Baroni Urbani & De Andrade, 2003b: 388, fig. 150 (w.q.) NEW GUINEA.

Worker
Head as broad as long and with the sides gently diverging posteriorly. Vertex in full face view gently convex. Clypeus reduced and about as long as the antennal sockets. Anterior border of the clypeus truncate. Frontal carinae far from each other, not 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 on the last fourth only. 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 sulcus. Eyes visible as a dark dot below the integument, small and on the middle of the head sides. First funicular joint slightly broader than long. 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 7-8 denticles before the pointed apical tooth. Palp formula 2,2.

Mesosoma convex and shorter than maximum head length (mandibles included) in profile. Pronotal and propodeal sutures absent. Basal face of the propodeum declivous posteriorly. Declivous face of the propodeum gently sloping posteriorly. Sides between the basal and declivous faces of the propodeum weakly angulate. Sides of the declivous face superficially marginate. Propodeal spiracle round and above mid height in lateral view.

Petiole subrectatlgular and slightly flattened. Anterior border of the petiole straight and anterolaterally weakly carinate. Ventral process of the petiole large, stout, subtriangular and pointed backwards. Postpetiole in dorsal view with gently convex sides. 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 tergites and sternites curved ventrally.

Legs short. All tibiae incrassate and with a pectinate spur. Spurs of fore legs without basal spine. Fore basitarsi longer than the mid ones. Hind basitarsi about 1/3 shorter than hind tibiae. Second tarsomere of hind legs shorter than pretarsus. Pretarsal claws simple. Arolia absent.

Sculpture. Head and mesosoina minutely reticulorugose. Petiole and postpetiole sparsely punctate. Gaster smooth and with minute piligerous punctures, denser on the sides. Legs minutely 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 and absent on the antennae; (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, and the scapes with sparse hairs similar to type (2) but slightly shorter.

Colour. Dark ferrugineous-brown with the posterior half of the head and the dorsum of the mesosorna darker. Antennae and legs lighter.

Measurements in mm and Indices: TL 2.25-2.29; NL 0.54; HW 0.54-0.55; EL 0.03-0.04; SL 0.35; WL 0.60-0.64; PeL 0.14-0.15; PeW 0.25; HFeL 0.3-0.37; HTiL 0.30-0.31; HBaL 0.20; LS4 0.22-0.23; LT4 0.48; CI 100.0-101.8; SI 64.8; IGR 0.46-0.48.

Queen
Differing from the worker in the following details: eyes large, about 1/3 of the head length, composed by many facets and with ocular pilosity. Ocelli well developed.

Mesosoma longer than the head (mandibles included), 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 lamellaceous tooth. Basal face of the propodeum medially concave. Area between the basal and declivous faces of the propodeum superficially carinate and angulate on each side.

Sculpture: anterior half of the mesonotum punctate only. Scutellum reticulorugose. Punctation on the petiole, postpetiole and gaster more marked.

Measurements in mm and Indices: TL 2.96-3.05; HL 0.63; HW 0.63; EL 0.19-0.20; SL 0.40-0.41; WL 0.90-0.92; PeL 0.19-0.20; PeW 0.33-0.34; HFeL 0.48-0.50; HTiL 0.38-0.40; HBaL 0.27-0.29; LS4 0.29-0.33; LT4 0.63-0.69; CI 100.0; SI 63.5-65.1; IGR 0.46-0.48.

Type Material
Holotype worker from Papua New Guinea labeled: "PNG. Gulf Prov.: Ivimka camp. Lakekamu Basin, 7.7°S 146.8°E 120 m el., 12 Nov. 1996, R. R. Snelling #96-316, Lowland wet forest: ex sifted leaf litter"; 1 paratype worker same data as the holotype, both in.

Etymology
This species is named after Roy R. Snelling who collected it and loaned us these and many other important specimens in study.