Engel, Engel & Herhold & Davis & Wang & Thomas, 2021

Engel, Michael S., Herhold, Hollister W., Davis, Steven R., Wang, Bo & Thomas, Jennifer C., 2021, Stingless bees in Miocene amber of southeastern China (Hymenoptera: Apidae), Journal of Melittology 2021 (105), pp. 1-83 : 78

Koilotrigona Engel , new subgenus

ZooBank: urn:lsid:zoobank.org:act:7BD0BD04-5095-40E9-A1CF-F0AA922E47DF

TYPE SPECIES: Trigona fulviventris Guérin-Méneville, 1844 .

DIAGNOSIS: Like Aphaneuropsis (supra), this genus has four teeth but builds permanent support pillars in the nest and irregular horizontal brood combs. The subgenus is characterized by the following combination of traits: integument entirely dark brown to black, although metasoma sometimes orange to reddish orange (i.e., T. fulviventris ); forewing membrane uniformly infumate; mandible quadridentate; labrum bigibbous, with pronounced mediolongitudinal furrow; vertex with distinct postocellar ridge; distance from median ocellus to postocellar ridge an ocellar diameter or less; metatibia with distinct corbicula, with retromarginal fringe setae abundant.

ETYMOLOGY: The new subgeneric name is a combination of the Greek koílos (Κοίλος, meaning, “hollow” or “concave”) and Trigona . The gender of the name is feminine.

INCLUDED SPECIES: In addition to the type species, the subgenus currently includes T. braueri Friese and T. guianae Cockerell .