Key of the Trigona (Nostotrigona) Engel, 2021 species from Brazil (workers)

1. Face with wide distance between the epistomal suture and the lower tangent of the antennal socket of approximately 0.7× scape diameter (Fig. 6A and D); post-ocellar carina strongly elevated................................................. 2

– Face with narrow distance between the epistomal suture and the lower tangent of the antennal socket of approximately 0.3× scape diameter (Fig. 6G, J and M); post-ocellar carina short and smooth......................................... 3

2(1). Scape with erect setae approximately 0.9× scape diameter (Fig. 6B); metasoma elongated, approximately 2× longer than wide............................................................................ Trigona recursa Smith, 1863 .

– Scape with erect setae approximately 1.3× scape diameter (Fig. 6E); metasoma subtriangular, approximately 1.2× longer than wide........................................................................... Trigona daianeae sp. nov.

3(1). Metabasitarsus distinctly enlarged on the apical half of the posterior margin, forming an acute angle (Fig. 6I); mesoscutum with long setae (0.26 mm), approximately 1.9× the scape diameter; labrum slightly protuberant medially.................................................................................................... Trigona juvenili sp. nov.

– Metabasitarsus with rather parallel sided, their posterior apical extremity almost rectangular to slightly produced downward (Fig. 6L and O); mesoscutum with relatively short setae (between 0.19 mm to 0.22 mm), approximately 1.5× the scape diameter; labrum rounded medially............................................................................... 4

4(3). Metasoma subtriangular, approximately 1.2× longer than wide (Fig. 7A); upper frons with erect setae approximately 0.8× scape diameter................................................................ Trigona permodica Almeida, 1992 .

– Metasoma elongated, approximately 2× longer than wide (Fig. 7B); upper frons with erect setae approximately 1.4× scape diameter.................................................................... Trigona mandaloriana sp. nov.