Proceratium lattkei

Identification
A member of the micrommatum clade. Resembles its outgroup Proceratium transitionis and also the members of the goliath group (stictum clade) by sharing with them the broad frontal carinae and the dense, long pilosity. lattkei differs from transitionis and the members of the stictum clade by the clypeus reduced and triangular instead of broad and strongly protruding anteriorly. Proceratium lattkei also differs from the other members of the stictum clade by the spur of the fore legs without a basal spine and by the palp formula 3,2 instead of 4,3.

Differing from its outgroup species, transitionis, in the worker, by the clypeus narrow and triangular instead of broad and subrectangular and by the propodeal dorsum without tumulus; and differing from all the other in-group species of the micrommatum clade, in the worker, by the mid legs with spur and by the broad, diverging frontal carinae. (Baroni Urbani and de Andrade 2003)

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

Nomenclature

 *  lattkei. Proceratium lattkei De Andrade, in Baroni Urbani & De Andrade, 2003b: 124, fig. 58 (w.) VENEZUELA.

Worker
Head longer than broad and with slightly convex sides. Vertex in full face view convex. Clypeus corresponding to a triangular tooth between and slightly longer than the antennal sockets. Antennal socket with broad torulus. Frontal carinae broad, separate from each other, covering part of the antennal insertions. Frons with a central sulcus. Frontal area behind the frontal carinae almost flat. Lateral expansions of the frontal carinae relatively broad, slightly raised, strongly diverging on the two anterior thirds and parallel, low and marginate on the posterior third. Genal carinae marked, prolonging towards the hypostomal bridge and bounding a slightly concave gular area. A sulcus is present between the genal carinae and the gular area. Eyes present, composed by a clearly convex facet placed below the midline of the head. Ocelli absent. Scapes thicker in the distal half and well 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 4 small teeth before the apical tooth. Palp formula probably 3,2.

Mesosoma in side view slightly convex. Promesonotal and propodeal sutures absent. Promesopleural and mesometapleural sutures impressed on the ventral hall only. Basal face of the propodeuln gently sloping posteriorly with traces of a transversal, superficial impression. The sides between basal and declivous propodeal faces angulate. Declivous lace of the propodeum with the sides weakly crenulate. Ventral part of the propodeal lobes truncate, dorsal part with a round tooth with crenulate border.

Petiole slightly longer than broad, subparallel in the anterior fourth and convex posteriorly in dorsal view. Anterior border of the petiole entirely carinate and medially concave. Ventral process of the petiole small and subtraangular. Postpetiole about 1/2 of the length of the gastral tergite I (LT4), with convex sides in dorsal view. Posterior half of the postpetiolar dorsum with a broad, short tumulus in the middle. Postpetiolar sternite anteromedially with a marked subtriangular border. Posterior half of the postpetiolar sternite weakly convex. Constriction between postpetiole and gastral segment I deeply impressed. Gastral tergite I strongly rounded. Gastral sternite I (LS4) very short medially. Sides of gastral sternite I carinate. Remaining gastral tergites and sternites curved ventrally.

Legs slightly elongate. Mid tibiae with spur. Spurs of fore legs without a basal spine. Fore basitarsi longer than the mid ones. Hind basitarsi about 1/7 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 very small.

Sculpture. Head, mesosoma, petiole and postpetiole irregularly reticulate-foveolate and granulate, some granules raised as small peaks. Lower meso- and metapleurae with irregular, longitudinal rugosities. Anterodorsal half of the gaster smooth and sparsely granulate, densely reticulate-granulate on the remaining parts. Legs and antennae superficially granite-punctate.

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

Colour dark ferrugineous-brown with slightly lighter legs.

Measurements in mm and Indices: TL 4.82; HL 1.12; HW 1.02; EL 0.08; SL 0.69; WL 1.30; PeL 0.51; PeW 0.45; HFeL 1.00; HTiL 0.78; HBaL 0.67; LS4 0.21; LT4 1.10; CI 91.1; SI 61.6; IGR 0.19.

Type Material
Holotype worker from Venezuela labelled: "Venez. Sucre, Cerro Humo via Las Melenas, 950m, 97 km NW Irapa, 10°41'N-62"37'W, 12.V.1993, J. Lattke", in.

Etymology
This species is named after John Lattke the collector of the material on which this species is based.