Proceratium terroni

Identification
A member of the toschii clade and differing from its sister species Proceratium toschii, in the worker, by the lack of suberect, long hairs on the head and on the mesosoma. Both species share a shining postpetiole, a relatively rare trait appearing only among a few species of the silaceum clade. (Baroni Urbani and de Andrade 2003)

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

Nomenclature

 * coecum. Proceratium coecum Terron, 1981: 96, fig. 2 (w.) CAMEROUN. [Junior secondary homonym of Ponera caeca Donisthorpe, 1949b: 491, above.] Replacement name: terroni Bolton, 1995b: 367.
 *  terroni. Proceratium terroni Bolton, 1995b: 367. Replacement name for Proceratium coecum Terron, 1981: 91. [Junior secondary homonym of Ponera caeca Donisthorpe, 1949b: 491.] See also: Baroni Urbani & De Andrade, 2003b: 285.

Worker
Baroni Urbani and de Andrade (2003) - Head longer than broad, with weakly convex sides gently converging into a strongly convex vertex. Clypeus medially reduced, subconvex, between the and about as long as the antennal sockets. Antennal socket with broad torulus. Frontal carinae raised, very close each other on the two anterior thirds gently convex and connected each other and almost perpendicular to the head capsule on the last third. Lateral expansions of the frontal carinae narrow. Anterolateral area close to the antennal insertions impressed. Genal carina absent. Gular area not impressed. Eyes absent. First funicular joint slightly longer than broad. Funicular joints 2-10 much broader than long. Last funicular joint about as long as the sum of joints 7-10. Scapes much short of the vertexal margin and gently thickening apically. External border of the mandibles flat. Masticatory margin of the mandibles with 3 denticles before the pointed apical tooth. Palp formula 3,2.

Mesosoma gently convex and shorter than maximum head length (mandibles included) in profile. Promesopleural and meso-metapleural sutures iinpressed ventrally only. Basal face of the propodeum gently declivous posteriorly. Area between the basal and declivous faces of the propodeum gently concave medially and with a blunt tooth on each side. Propodeal lobes subround. Propodeal spiracle round and above the mid height in lateral view. Metapleural gland bulla inflated and transparent.

Petiole with the anterior half sloping anteriorly and with the posterior half convex in profile, broader than long in dorsal view; its sides anteriorly shortly diverging and posteriorly convex. Anterior border of the petiole V-shaped and marginate. Ventral process of the petiole lamelliform, subrectangular with concave ventral margin. Postpetiole in dorsal view with the anterior border slightly broader than the petiole; its sides gently diverging posteriorly. Postpetiolar sternite anteromedially with a large subconvex projection. Posterior half of the postpetiolar sternite convex. Constriction between postpetiole and gaster impressed. Gastral tergite 1 strongly convex and slightly longer than the postpetiole. Gastral sternite I subround and strongly projecting anteriorly. Remaining gastral tergites and sternites curved ventrally.

Legs slender and slightly elongate. All tibiae with a pectinate spur. Spurs of fore legs without basal spine. Fore basitarsi longer than the mid ones. Hind basitarsi 1/5 shorter than hind tibiae. Second tarsomere of hind legs subequal in size to the pretarsus. Pretarsal claws simple. Arolia developed.

Sculpture. Head, mesosoma and petiole granulate, the granulation strongly marked on the head and on the mesosoma, superficial on the petiole. Postpetiole, gaster and legs smooth and with sparse, minute, superficial, piligerous punctures.

Body covered by hairs of three main types: (1) short, dense, decumbent on the whole body, absent from the posterior half of the metapleurae, on the postero-lateral sides of the petiole and on the postpetiolar sternite; (2) longer than type (1), subdecumbent and restricted only on the posterior half of the metapleurae, on the postero-lateral sides of the petiole and on the postpetiolar sternite; (3) shorter than hair type (1), dense, subdecumbent and decumbent on the funicular joints. In addition the funicular joints bear whitish, thick, appressed, short, sparse hairs.

Colour light brown.

Measurements in mm and Indices: TL 2.53; HL 0.69; HW 0.61; EL absent; SL 0.46; WL 0.70; PeL 0.21; Pew 0.25; HFeL 0.48; HTiL 0.38; HBaL 0.27; LS4 0.12; LT4 0.44; CI 88.4; SI 66.7; IGR 0.27.

Type Material
Baroni Urbani and de Andrade (2003) - Proceratium coecum Worker. Original description. Type locality: Kala, Cameroon. Type material worker labeled: "P. sp 2 OL, Cameroun: Kala, 950 m, (18 km W Yaounde), tamisage tissus ligneux en decomposition, 10.X.1972, G. Terron Leg., Proceratium coecum Terron, Holotype", in CIRA, examined.