Proceratium creek

Specimens have been collected from pitfall traps in gopher burrows.

Identification
The workers of Proceratium creek are the largest of the pergandei clade.

This species has a low, rounded petiole, similar to Proceratium pergandei, but the antennal scapes are relatively longer, exceeding the posterior margin of the head when laid back against the head. The workers are apparently larger than those of P. pergandei, although so few specimens have been seen that the usefulness of this character state is uncertain. Any specimen that appears to be a giant P. pergandei should be checked to see whether it is this rare species. This species is similar to the western species Proceratium compitale, which is known from a few specimens taken in caves in southern Texas (Ward 1988).

Distribution
This species is known only from Thomasville, Thomas County, Georgia, Lafayette County, Florida and Arkansas. A presumed male was taken in a Malaise trap at Tall Timbers Research Station, Leon County, Florida.

Distribution based on Regional Taxon Lists
Nearctic Region: United States.

Biology
All specimens, except for a presumed male of this species, were taken in pitfall traps placed in burrow systems of pocket gophers (Geomys pinetis) by Paul Skelley and Peter Kovarik. Trapping in these burrow systems is not a simple affair: the gopher must be trapped and removed first, or it will fill in the pitfall traps; the pitfall trap is then be set in the burrow system, and covered with a board and soil carefully so that the trap does not fill with soil (Skelley and Woodruff 1991).

Nomenclature

 *  creek. Proceratium creek De Andrade, in Baroni Urbani & De Andrade, 2003b: 207, figs. 86-89 (w.q.m.) U.S.A.

Worker
Head longer than broad, its sides subparallel on the two anterior thirds and strongly converging on the posterior third. Vertexal margin convex. Anteromedian part of the clypeus rectangular and strongly protruding anteriorly. Anteromedian part of the clypeus dorsally with a variably marked inverted Y-shaped carina. Frontal carinae gently diverging posteriorly, slightly raised and not very close to each other. Lateral expansions of the frontal carinae narrow. Head anterolaterally with a short, longitudinal carina. Genal carina absent. Gular area not impressed. Eyes small and represented by a dark pigmented slightly differentiate integumental dot placed in the middle of the sides of the head. First funicular joint 1/2 longer than broad. Funicular joints 2-10 longer than broad. Last funicular joint slightly shorter than the sum of joints 8-10. Scapes long and slender, slightly surpassing the vertexal margin. Antennal torulus placed behind the lateral border of the clypeus. Masticatory margin of the mandibles with 5-6 denticles before the pointed apical tooth. Palp formula 4,3.

Mesosoma longer than the head length (mandibles included). Promesopleural and meso-metapleural sutures impressed ventrally only. Propodeal dorsum between basal and declivous faces marked by a concave carina. Declivous face of the propodeum with a semitransparent lamella on each side, the lamella denticulate on each side between the basal and declivous faces. Propodeal spiracle round and placed over the mid height in lateral view.

Petiole in side view convex on the two posterior thirds, with the sides diverging on the anterior third and convex posteriorly in dorsal view. Anterior border of the petiole gently concave and carinate, the carina weakly denticulate on each side. Ventral process of the petiole lamelliform, triangular and curved backwards. Postpetiole anteriorly as broad as or slightly broader than the petiole; its sides gently diverging and convex posteriorly. Postpetiolar sternite anterornedially with a marked triangular projection. Posterior half of the postpetiolar sternite convex. Constriction between postpetiole and first gastral segment impressed. Gastral tergite I feebly tumuliform on the curvature.

Legs slender. All tibiae with a pectinate spur. Spurs of fore legs with basal spine. Fore basitarsi as long as the mid ones. Hind basitarsi about 1/7 shorter than hind tibiae. Second tarsomere of hind legs longer than the pretarsus. Pretarsal claws simple. Arolia absent.

Queen
Differing from the worker in the following details: eyes about 1/6 of the head length and with well defined ommatidia. Ocular pilosity present. Ocelli present.

Mesosoma robust. Scutellum shorter than the maximum length of the basal face; its sides gently converging into a convex posterior border. Metanotum with a tooth. Propodeal lamellae slightly narrower.

Postpetiole anteriorly slightly broader than the petiole.

Sculpture and pilosity as in the worker.

Measurements in mm and Indices: TL 6.68; HL 1.30; HW 1.04; EL 0.21; SL 1.06; WL 1.92; PeL 0.60; PeW 0.54; HFeL 1.42; HTiL 1.24; HBaL 1.20; LS4 0.52; LT4 1.74; CI 80.0; SI 8 1.5; IGR 0.30.

Sculpture. Head punctate and minutely rugulose, the punctures resembling minute reticulation close to the frontal carinae. Mesosoma, petiole, postpetiole and legs granulopunctate, the granulation slightly larger on the petiole and postpetiole. Metapleurae with additional, thin, rugosities. First gastral tergite superficially shining and covered by minute, piligerous punctures; its lateral and posterior border variably granulate. Legs punctate.

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

Colour ferruginous-brown.

Measurements in mm and Indices: TL 5.50-5.70; HL 1.17-1.20; HW 0.94-0.98; EL 0.04-0.05; SL 0.96-1.00; WL 1.52-1.60; PeL 0.48-052; PeW 0.44-0.49; HFeL 1.22-1.26; HTiL 1.08- 1.13; HBaL 0.90-0.96; LS4 0.42-0.45; LT4 1.32-1.40; CI 79.7-82.0; SI 81.3-83.3; IGR 0.31-0.33.

Male
Head as broad as long. Vertex in full face view convex. Vertexal margin not carinate. Clypeus dorso-medially convex and with weakly convex anterior border. Frontal carinae thin, low and diverging posteriorly. Frontal area with sulcus. Ocelli large. Compound eyes large and placed mostly on the anterior part of the head sides. Scapes slightly surpassing the vertex. First funicular joint about 2/3 of the length of the second joint. Joints 2-11 longer than broad. Last funicular joint slightly shorter than the sum of joints 10-11. Mandibles with two, minute basal denticles and with a pointed apical tooth. Palp formula 5,3.

Mesosoma robust. Pronotum and anterior third of mesonotum almost perpendicular to the posterior two thirds of the mesonotum. Posterior two thirds of mesonotum weakly convex. Parapsidal furrows marked. Scutellum as high as the mesonotum; posterior border of scutellum round. Basal and declivous faces of the propodeum very distinct. Sides of the basal face of the propodeum gently converging posteriorly and separated from the declivous face by a strong transversal carina forming a tooth on each side. Declivous face of propodeum laterally strongly carinate. Metanotum with a median spine-like projection. Propodeal lobes round. Propodeal spiracles small.

Petiole in side view declivous in the anterior third and convex in the two posterior thirds. Sides of the petiole in dorsal view gently diverging in the anterior third and convex in the two posterior thirds. Anterior border of the petiole concave and strongly carinate. Subpetiolar process subtriangular and lamelliform. Postpetiole anteriorly slightly broader than the petiole; postpetiolar sides weakly convex. Anterior border of the postpetiolar sternite with a superficial triangular "lip". Posterior half of the postpetiolar sternite gently convex. Gastral tergite I round. Gastral sternite I large. Remaining gastral tergites and sternites slightly curved ventrally.

Legs as in the worker but much more elongate.

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

Sculpture. Head, mesosoma and scutellum punctate and rarely minutely granulate. Areas close to the antenna1 insertions and propleurae with additional thin, slightly longitudinal rugosities. Propodeurn and petiole granulate and with thick, irregular rugosities. Postpetiole granulopunctate. Gaster and legs with minute punctures.

Pilosity as in the worker.

Colour. Light brown with lighter antennae and legs.

Measurements in mm and Indices: TL 5.65; HL 0.90; HW 0.90; EL 0.46; SL 0.68; WL 2.02; PeL 0.52; Pew 0.50; HFeL 1.28; HTiL 1.08; HBaL 1.00; LS4 0.76; LT4 1.26; CI 100.0; ST 75.5; IGR 0.60.

Type Material
Holotype worker from Georgia, United States, labelled: "Georgia: Thomas Co., S. Thomasville, 1.8 mi. S. jct Metcalf Rd. & Springhill Rd., 10-17-XII-1996, P. Skelley & P. Kovarik, Geomys burrow pitfall", in, three paratype workers, same data as the holotype, one in MCZ, one in and one in ABSC.

Etymology
This species is named after the Creeks, an Indian tribe from Georgia.

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.