Proceratium taino

Specimen labels show this species has been collected from forest litter, tropical evergreen forest litter and in a mixed hardwood-pine valley forest.

Identification
A member of the micrommatum clade. Resembling Proceratium mexicanum and Proceratium dominicanum, but differing from mexicanum, in the worker and gyne, by the following characters: gastral sternite I laterally flat instead of protruding anteriorly and by the mid basitarsi without a hair long 1/2 of the mid basitarsal length or longer; and from dominicanum, in the gyne, by the TL = 4.00 mm instead of < 3.10 mm and by the IGR = 0.20 instead of ≥ 0.24 (Baroni Urbani and de Andrade 2003)

Distribution based on Regional Taxon Lists
Neotropical Region: Dominican Republic, Greater Antilles.

Castes
Males are unknown.

Nomenclature

 *  taino. Proceratium taino De Andrade, in Baroni Urbani & De Andrade, 2003b: 186, fig. 80 (w.q.) DOMINICAN REPUBLIC.

Worker
Head slightly longer than broad, narrower anteriorly than posteriorly. Vertex in full face view weakly convex and medially superficially incised. Clypeus reduced, triangular, slightly longer than the antennal sockets. Antennal socket with broad torulus. Frontal carinae close each other, not covering the antennal insertions. Frontal area behind the frontal carinae weakly protruding. Lateral expansions of the frontal carinae relatively narrow, raised, subparallel or gently diverging posteriorly. Genal carinae poorly marked. A superficial sulcus between the genal carinae and the gular area. Eyes composed by a clearly convex facet and placed below the mid-line of the head. Scapes thicker in the distal half and short of the vertexal margin. First funicular joint slightly shorter than 1/2 of their width. Funicular joints 2-10 broader than long. Last funicular joint about as long as the sum of joints 6-10. Mandibles with 4 denticles before the apical tooth. Palp formula probably 3,2.

Mesosoma slightly convex in profile. Promesonotal and propodeal sutures superficially impressed. Promesopleural and mesometapleural sutures impressed on the ventral half only. Basal face of the propodeurn gently convex anteriorly, declivous posteriorly and with a superficial, transversal sulcus close to the declivous face; postero-lateral border of the sulcus subangulate. Declivous face of the propodeum with crenulate sides. Propodeal lobes ventrally truncate and dorsally obtuse and with crenulate margin. Propodeal spiracles tumuliform and oriented downwards. Metapleurae below the propodeal spiracles concave.

Petiole about as long as broad, with the sides subparallel in the anterior third and convex posteriorly in dorsal view. Anterior border or the petiole concave and angulate on each side. Ventral process of the petiole triangular. Postpetiole slightly less than 1/2 of the length of the gastral tergite I (LT4), in dorsal view with convex sides. Postpetiolar sternite anteromedially with a subtriangular projection. Posterior half of the postpetiolar sternite slightly convex or straight. Constriction between postpetiole and gastral segment I impressed. Gastral tergite I relatively long, sub-oval. Gastral sternite I very short medially. Sides of gastral sternite I neither carinate nor protruding anteriorly. Remaining gastral tergites and sternites curved ventrally.

Mid tibiae without spur. Spurs of fore legs without basal spine. Fore basitarsi longer than the mid ones. Hind basitarsi about 1/6 shorter than hind tibiae. Second tarsomere of mid and hind legs longer than third and fourth tarsomeres, and slightly shorter than pretarsus. Fourth tarsomere of fore legs much longer than each tarsomere 1-3, and shorter than the sum of tarsomeres 1-2. Pretarsal claws simple. Arolia very small.

Sculpture. Head punctate, sparsely granulate. Mesosoma, petiole and postpetiole granulate-punctate and with thin, irregular rugae, the granules superficial on the center of the pronotum and mesonotum, marked on the petiole and postpetiole. First gastral tergite smooth and minutely punctate; its sides and ventral part granulate-punctate. Legs punctate.

Body covered by hairs of three main types: (1) short, dense, subdecumbent on the whole body, in some parts of the mesosoma erect; (2) long, suberect on the whole body, slightly longer on the anterior part of the pronotum and on the postpetiolar sternite, absent on the funiculi; (3) shorter than hair type (I), dense, decumbent on the funicular joints only. In addition the funicular joints bear whitish, thick, appressed, sparse hairs and suberect hairs similar to type (I) but slightly shorter.

Colour dark ferrugineous-brown.

Measurements in mm and Indices: TL 3.70-4.30; HL 0.85-0.94; HW 0.76-0.86; EL 0.06; SL 0.56-0.64; WL 1.00-1.16; PeL 0.37-0.40; PeW 0.35-0.40; HFeL 0.68-0.85; HTiL 0.57-0.68; HBaL 0.46-0.56; LS4 0.18-0.22; LT4 0.91-1.14; CI 89.4-91.5; SI 65.9-68.1; IGR 0.19-0.20.

Queen
(tentative attribution). Differing from the worker in the following details: eyes large and composed by many facets, long about 114 of the head length and with ocular pilosity. Ocelli well developed.

Mesosoma robust and convex in profile. Parapsidal furrows weakly marked. Scutellum with the sides convcrging posteriorly and with the posterior border rounded. Metanotum without tooth or spine-like projection. Basal face of the propodeum very short, laterally sub-angulate, medially gently incised and almost as flat as the declivous face. Petiole slightly longer than broad.

Sculpture: center of pronotum and mesonotum smooth and with minute piligerous punctures.

Measurements in mm and Indices: TL 4.01; HL 0.87; HW 0.79; EL 0.20; SL 0.58; WL 1.12; PeL 0.37; Pew 0.35; HFeL 0.51; HTiL 0.63; HBaL 0.51; LS4 0.22; LT4 1.06; CI 90.8; SI 66.7; IGR 0.21.

Type Material
Holotype worker from the Dominican Republic labelled "La Vega Prov. PN. A Bermudez, 4 km SW Cienaga 1200 m, 21.VII.1995. S. + J. Peck for. litter, 95-42", in.

Etymology
From Taino, the name of the inhabitants of the island of Hispaniola at the time of the European arrival in the Caribbean.

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.
 * Perez-Gelabert D. E. 2008. Arthropods of Hispaniola (Dominican Republic and Haiti): A checklist and bibliography. Zootaxa 1831:1-530.