Trigonisca Moure 1950

Trigonisca Genus Group

The Trigonisca genus group clade, comprising the extant genus Trigonisca and the extinct genus Exebotrigona, is united by the combination of a minute body size, with a length typically 4.5 mm or frequently less, and a forewing length of 4 mm or less; a distinctly broadened base to the marginal cell, with a basal angle (angle formed within the marginal cell between pterostigmal margin and r-rs) of 68°–90°, and the marginal cell, at tangent of pterostigmal apex, broader than submarginal cell area; the posterior margin of the metatibia nodulose or tuberculate, sometimes weakly so (apparently not nodulose in Exebotrigona), owing to prominent bristle bases; and the setae of the inner surface of the metabasitarsus arranged in transverse rows (Michener, 1990, 2007).

Presently, there are 45 species contained in the Trigonisca genus group, including the species described herein, and these are arranged into four subgenera, which are sometimes treated as distinct genera (e.g., Moure, 1950). The analysis of Rasmussen and Cameron (2010) indicated the likelihood that Leurotrigona s.l. is paraphyletic, and so is treated as two distinct groups herein. Leurotrigona s.str. and Exochotrigona, new subgenus, each with two species (Pedro and Camargo, 2009; see below), while Celetrigona has four species (Camargo and Pedro, 2009) and Trigonisca s.str. (= Dolichotrigona Moure) has 37 (Albuquerque, 1990; Ayala, 1999; Albuquerque and Camargo, 2007; Camargo and Pedro, 2005; Alvarez and Lucia, 2018; herein). Five species of the group are currently recorded as occurring within Colombia: Trigonisca (Exochotrigona) crispula Pedro and Camargo, T. (Celetrigona) longicornis (Friese), T. (Trigonisca) schulthessi (Friese), T. (T.) buyssoni (Friese), and T. (T.) graeffei (Friese) (Nates-Parra, 2001; Smith-Pardo, 2003; Camargo and Pedro, 2009; Pedro and Camargo, 2009). Examination of numerous workers of Trigonisca in Colombian copal (Engel, personal obs.), individuals of which are not uncommonly encountered as inclusions, reveal that they are universally T. schulthessi, of which the injudiciously described T. ameliae Penney (Penney et al., 2013) is a junior synonym (new synonymy).