Myanmyia Grimaldi

Grimaldi, David A., Arillo, Antonio, Cumming, Jeffrey M. & Hauser, Martin, 2011, Brachyceran Diptera (Insecta) in Cretaceous ambers, Part IV, Significant New Orthorrhaphous Taxa, ZooKeys 148, pp. 293-332 : 322

Myanmyia Grimaldi gen. n.

Diagnosis.

Distinctive small flies (body length less than 1.5 mm) with antennal stylus arista-like and terminal, having a single article; face without ptilinal suture; median margins of eyes very close on frons; maxillary palpus two-segmented; mesonotum with dorsocentral and scutellar setae; wing venation highly reduced, with R2+3 and R4+5 each unbranched, M unbranched and evanescent at both ends, Cu simple; female with pair of long, digitate, unsegmented cerci.

Etymology.

From Myanmar, country of origin, and -myia, a common suffix referring to the feminine Greek word for fly.

Type Species.

Myanmyia asteiformia sp. n. By present designation.

Discussion.

This is a perplexing little fly. Chaetotaxy of the thorax, the wing venation, and even body shape are strikingly similar to acalyptrate flies in the Asteiidae . Convergent wing features of the two groups include short R1 and R2+3 veins; a straight R4+5 that meets the tip of the wing, and even microtrichia that are arranged in rows. However, Myanmyia is not even a cyclorrhaphan, by virtue of the terminal (versus dorsal) arista-like stylus, lack of a ptilinum, and presence of two-segmented (vs. 1-segmented) palpi. With the exception of a few very basal Recent and extinct Platypezidae , almost all other Cyclorrhapha have a dorsal arista. Two-segmented palpi exclude Myanmyia from the Eremoneura (the apparent basal segment of the two segmented palpi seen in some Phoridae is probably a palpifer [ Cumming and Wood 2009]). While some empidoids (e.g., Cretaceous Nemedina genus-group species [ Grimaldi and Cumming 1999]) have short R veins and faint M and Cu veins, the branching pattern for these flies differs significantly at the base from that of Myanmyia .