Trigonisca (Exochotrigona) Engel 2019, new subgenus

Exochotrigona Engel, new subgenus

TYPE SPECIES: Leurotrigona pusilla Moure and Camargo in Moure et al., 1988.

DIAGNOSIS: As for the genus as well as: Small bees, 2.30 mm or less in total body length, forewing length 1.90 mm or less; integument smooth, shining, largely black to dark brown throughout without true yellow maculation, with labrum, clypeus, mandible, scape, tegula, and mesoscutellum sometimes with yellowish to ferruginous areas.

Worker. Head slightly wider than long; clypeus with simple setae; vertex rounded; preoccipital area rounded; scape shorter than torulocellar distance; labrum simple; mandible bidentate; malar space short, as long as flagellar diameter. Transscutal sulcus between axillae shallowly impressed; mesoscutellum comparatively flat and low, acutely rounded apically in profile and slightly raised above level of metanotum; metatibia subtriangular, 2.5–2.6× as long as wide; posterior margin of metatibia somewhat sinuous, with distal angle projected; corbicular setae simple; inner surface with keirotrichiate zone faintly elevated, posterior glabrate zone not depressed; parapenicillum markedly sinuate; metabasitarsus subrectangular, without basal sericeous area on inner surface, with setae arranged in 6–7 transverse rows; forewing shorter than body; hind wing with 5 distal hamuli.

Drone. Metasomal sternum V with apical margin comparatively straight or concave (with deep, broad medial emargination in Leurotrigona); sternum VII relatively transverse (subtriangular, trapezoidal, or subrectangular in Trigonisca and Celetrigona).

ETYMOLOGY: The new subgeneric name is a combination of the Greek exochos (meaning, “jutting out”), a reference to the projecting and prominent apical posterior angle of the metatibia, and the generic name Trigona Jurine. The gender of the name is feminine.

INCLUDED SPECIES: Trigonisca pusilla (Brazil, French Guiana, Peru) and T. crispula (Colombia). Both species are diagnosed and described in detail by Pedro and Camargo (2009).