Heterotrigona (Sahulotrigona) atricornis (Smith) Engel & Rasmussen, 2017

Engel, Michael S. & Rasmussen, Claus, 2017, A new subgenus of Heterotrigona from New Guinea (Hymenoptera: Apidae), Journal of Melittology 2017 (73), pp. 1-16 : 11

Heterotrigona (Sahulotrigona) atricornis (Smith) , new combination

( Figs. 11–14 )

Trigona atricornis Smith, 1865: 94 .

Trigona (Tetragona) atricornis Smith ; Michener, 1965: 231.

Trigona (Heterotrigona) atricornis Smith ; Michener, 1990: 127.

Platytrigona atricornis (Smith) ; Rasmussen, 2008: 26 .

DIAGNOSIS: As currently circumscribed, H. atricornis encompasses two color morphs (vide Michener & Sakagami, 1990). Some individuals, including the holotype, are of the yellowish-orange morph ( Fig. 13 ), a color pattern generally similar to Papuatrigona genalis (Friese) , while others are more chestnut brown in coloration ( Figs. 11, 12 ). In addition to color, the dark morph appears to have denser and slightly longer pilosity, while the yellowish orange morph has setae denser and longer only in on the lower portion of the mesepisternum. It remains to be tested whether or not these color morphs are truly conspecific. For now, the species can be distinguished from H. paradisaea by the lighter color (the above species is largely black), whether chestnut brown or yellowish orange. In addition, H. atricornis has the fifth and sixth terga more sparsely pubescent, the preapical teeth of the mandible less developed, and six distal hamuli on the hind wing. The holotype of H. atricornis belongs to the yellowish-orange morph and is deposited in Oxford (we have not had the opportunity to examine the type of this species).

MATERIAL EXAMINED: Papua New Guinea: 1⚲, New Guinea (NE) [Papua New Guinea], Boana Mission [near Boana, Morobe Province, Nawae District], Huon Pen. [Peninsula], 900 m, ix-4–5-1956 [4–5 September 1956], E.J. Ford, Jr. ( SEMC, dark morph); 1⚲, PNG [ Papua New Guinea]: Chimbu Province, Wara Sera Research Station, Crater Mtn. Conservation Area, October 6–10, 2000, A.S. & M.F. Whiting ( AMNH, yellow morph). Indonesia (Papua Province): 3⚲⚲, tusschen bivak [between bivouac, or “camp”], [“Jasa am”, handwriting is nearly illegible] Njao [Njao is situated along the border of northwestern Sandaun Province, Papua New Guinea and Muara Tami District, Kota Jayapura, Papua Province, Indonesia], 14.6.10 [14 June 1910], [illegible: possibly “v.k.” which is likely an abbreviation for “van Kampen” as Pieter Nicolaas van Kampen (1878–1937), a Dutch zoologist mostly known for his work in herpetology, is known to have collected near Njao in mid-June 1910 (e.g., Kampen, 1914; Blöte, 1936), and these specimens were identified as “ T. atricornis ” by Friese who subsequently sold them to the AMNH; in fact, these specimens could be some of those referenced by Friese (1915: p. 4) in his account of bees collected in northern New Guinea by van Kampen and K. Gjellerup in 1910] ( AMNH, yellow morph).

Figures

Figures 11–14. Workers of Heterotrigona (Sahulotrigona) atricornis (Smith), from eastern Papua New Guinea (non-type specimens). 11. Lateral habitus of dark morph. 12. Facial view of dark morph. 13. Lateral habitus of yellowish orange morph. 14. Facial view of yellowish orange morph.