Centromyrmex alfaroi

The biology of C. alfaroi is unknown but these large ants are presumed to be entirely subterranean, and thus are rarely encountered. In 1988 S. Cover observed closed turrets projecting from clay soil in open sunlit ground surrounding the River Station at La Selva Biological Station. Excavation yielded workers and males, and Cover suggested the turrets were the result of a premating flight excavation. Males have been collected at blacklights.

Identification
A member of the brachycola species group.

Distribution
Kempf listed records for Costa Rica, northwestern Bolivia and central Brazil.

Distribution based on Regional Taxon Lists
Neotropical Region: Bolivia, Brazil, Costa Rica, Ecuador, French Guiana.

Nomenclature

 *  alfaroi. Centromyrmex alfaroi Emery, 1890b: 40 (w.) COSTA RICA. Emery, 1906c: 115 (q.). [Also described as new by Emery, 1894k: 46.] See also: Kempf, 1967b: 404.

Worker
Kempf (1967) - According to the original description, this species is larger than Centromyrmex brachycola, smaller than Centromyrmex gigas (the total length given for the holotype, a single-spread measurement, is 7.75 mm). Head broader than long with the sides converging cephalad. Clypeus convex, with an elevated median tumulus on disc, without a median longitudinal impression. Metapleura striate. Thorax strongly compressed at mesoepinotal junction, the basal face of epinotum grading continuously into the declivous face. Legs comparatively short and stout. Metatarsus of hind legs much shorter than tibiae. Petiole rather short, anterior face straight and oblique, dorsum completely rounded. Color dark ferruginous.

Queen
Kempf (1967) - Total length 8.8 mm; head length 1.39 mm; head width 1.60 mm; maximum diameter of eyes 0.53 mm; thorax length 2.77 mm; hind tibiae length 0.99 nun; hind metatarsus length 0.53 mm. Mandibles smooth and shining, with sparse, minute punctulae; mandibular line prolonged foreward on sides as a shallow groove; basal half of chewing border distinctly denticulate, apical half forming a sharp cutting edge without noticeable teeth. Clypeus with the anterior border conspicuously convex, with a prominent median tumulus, on disc. Antennal scapes almost reaching occipital corners. Compound eyes very large. Mesial spur of middle tibiae short and inconspicuous, not projecting beyond apex of tibia; lateral spurs missing both on middle and hind tibiae. Extensor face of hind tibiae with a few spine-like setae on apical half. Petiole as shown in Figs. 1 and 2. Gastric constriction weak. Sternum I of gaster without a prominent and marginate tuberosity beneath petiolar insertion. Wings (only hind wings preserved) hyaline, venation brown.