Nannotrigona, Cockerell, 1922

Jaramillo, Joanna, Ospina, Rodulfo & Gonzalez, Victor H., 2019, Stingless bees of the genus Nannotrigona Cockerell (Hymenoptera: Apidae Meliponini) in Colombia, Zootaxa 4706 (2), pp. 349-365 : 351

Key to the species of Nannotrigona (workers) present in Colombia

(Modified from Rasmussen & Gonzalez 2017)

1. Mesoscutum sparsely punctate, smooth and shiny among scattered punctures; small species, head width <1.6 mm ....................................................................................... N. schultzei (Friese, 1901)

- Mesoscutum and mesoscutellum densely and coarsely foveate, surface among foveae angular, ridge-like, giving foveae a rugulose appearance; larger species, head width> 1.8 mm ......................................................... 2

2(1). Posterior margin of mesoscutellum with shallow, narrow, and often triangular emargination; depth of emargination, as measured from an imaginary line between apices of teeth to its base, at most 0.5× diameter of F3, emargination at most as wide as the axilla............................................................................................ 3

- Posterior margin of mesoscutellum with deeper, broader, and semicircular emargination; depth of emargination 1.2× greater than diameter of F3, emargination much wider than width of axilla.............................................. 4

3(2). Base of antennal scape with long setae, at least 1.7–2.0× longer than width of scape; antenna usually black; T3–T6 sparsely covered by whitish or grayish, decumbent setae, integument largely visible among setae, not contrasting significantly with the dark brown to black integument of terga (Orinoquia and Amazon regions)............... N. melanocera ( Schwarz, 1938)

- Base of antennal scape with appressed or short erect setae, at most as long as half width of scape; antenna usually light reddish brown; T3–T6 densely covered by light reddish brown, decumbent setae, integument largely hidden among setae, and thus contrasting with the dark brown to black integument of terga (Caribbean and Andean regions)............. N. gaboi n. sp.

4(2). Base of antennal scape covered with short erect setae, setae length about 0.5–0.6× width of scape...................... 5

- Base of antennal scape with distinctly longer setae, at least 1.2× width of scape.................................... 6

5(4). Posterior margin of mesoscutellum with broad emargination, at least twice as broad as width of axilla; antenna usually black or darkened; face with appressed, plumose, whitish setae not completely obscuring integument........................................................................................... N. camargoi Rasmussen & Gonzalez, 2017

- Posterior margin of mesoscutellum with narrower emargination, at most 1.7× width of axilla; antenna usually light reddish brown; face with appressed, plumose, light reddish brown setae completely obscuring integument.......... N. pilosa n. sp.

6(4). Posterior emargination of mesoscutellum 1.8–2.0× width of axilla; yellow macula on lateral margin of mesoscutum absent (western Colombia and Province of Darién, Panamá)......................................... N. occidentalis n. sp.

- Posterior emargination of mesoscutellum narrower, about 1.5–1.6× width of axilla; yellow macula on lateral margin of mesoscutum present, faint or distinct (Andean and Caribbean regions)................................................ 7

7(6). Base of antennal scape with setae at most 1.5× width of scape; mesoscutellum 1.5× broader than long; macula on lateral margin of mesoscutum, axilla, and apical tooth of mesoscutellum distinct, bright yellow............... N. mellaria ( Smith, 1862)

- Base of antennal scape with longer setae, longest 1.8× width of scape; mesoscutellum narrower, less than 1.5× broader than long; macula on lateral margin of mesoscutum, axilla, and apical tooth of mesoscutellum reduced or faint yellow...................................................................................... N. tristella ( Cockerell, 1922)