Platytrigona Moure

Engel, Michael S., 2019, Notes on Papuasian and Malesian stingless bees, with the descriptions of new taxa (Hymenoptera: Apidae), Journal of Melittology 2019 (88), pp. 1-25 : 9

Subgenus Platytrigona Moure

The subgenus Platytrigona includes larger bees, with forewing lengths over 7 mm ( Figs. 10–13 ), and therefore can be easily separated from the smaller bees of the subgenera Sahulotrigona and Sundatrigona . The species of the subgenus are also distinctive for the pubescence of the basal area of the propodeum ( Figs. 22, 23 , 32 ) (pubescent also in the new subgenus described herein), and absence of stout, thick, black bristles on the vertex, mesoscutum, and mesoscutellum (present in Heterotrigona s.str., Sundatrigona , and the new subgenus described herein). Lastly, the posterior glabrate zone of the inner surface of the metatibia is narrower than the broad keirotrichiate zone, which differs from the condition of the new subgenus described below (vide infra), and the basal vein (1M) of the forewing is confluent or slightly distad 1cu-a ( Figs. 18–21 ) (rather than basad in the new subgenus). Platytrigona as so narrowly circumscribed [i.e., with H. hobbyi (Schwarz) removed to a separate subgenus], is likely related to Sahulotrigona as evidenced by the male genitalia ( Michener, 1990: his “ T. atricornis ” actually being H. taraxis ), while Heterotrigona s.str., Sundatrigona , and the new subgenus (vide infra) likely form a reciprical clade, each lineage diversifying on either side of Weber’s line. Clarification of this mater and the precise biogeographic boundaries of these lineages awaits surveys of the various archipelagos comprising the Moluccas, particularly from Seram to Buru, the Obi and Sulu Islands, and from Tanimbar across the Barat Daya Islands, Babar Islands, Sermata Islands, and Leti Islands toward Timor along with the eastern islands of the Lesser Sundas.

Platytrigona includes four species, with rather varied coloration ( Figs. 10–17 ), all of which are found in New Guinea and Kei Archipelago of the southeastern Moluccas: H. (P.) planifrons (Smith) , H. (P.) lamingtonia , H. (P.) flaviventris (Friese) , and H. (P.) keyensis .

Figures

Figures 10–13. Lateral habitus of workers of species of subgenus Platytrigona Moure. 10. Heterotrigona (Platytrigona) planifrons (Smith). 11. H. (P.) keyensis (Friese). 12. H. (P.) flaviventris (Friese). 13. Paratype of H. (P.) lamingtonia (Cockerell).

Figures 22–23. Propodeal basal areas of representative species of Platytrigona Moure. 22. Heterotrigona (Platytrigona) planifrons (Smith). 23. H. (P.) keyensis (Friese).

Figures 31–33. Details of worker of Heterotrigona (Platytrigona) lamingtonia (Cockerell). 31. Facial view. 32. Basal area of propodeum. 33. Wing venation.

Figures 18–21. Forewings species of subgenus Platytrigona Moure. 18. Heterotrigona (Platytrigona) planifrons (Smith). 19. H. (P.) flaviventris (Friese). 20. H. (P.) keyensis (Friese). 21. Paratype of H. (P.) lamingtonia (Cockerell).

Figures 14–17. Facial views of workers of species of subgenus Platytrigona Moure. 14. Paratype of Heterotrigona (Platytrigona) lamingtonia (Cockerell). 15. H. (P.) planifrons (Smith). 16. H. (P.) flaviventris (Friese). 17. H. (P.) keyensis (Friese).