MYSTEROMYIIDAE, Grimaldi, 2016

Grimaldi, David A., 2016, Diverse Orthorrhaphan Flies (Insecta: Diptera: Brachycera) In Amber From The Cretaceous Of Myanmar: Brachycera In Cretaceous Amber, Part Vii David A. Grimaldi, Bulletin of the American Museum of Natural History 2016 (408), pp. 1-132 : 81

MYSTEROMYIIDAE , NEW FAMILY

DIAGNOSIS: As for genus, below.

TYPE GENUS: Mysteromyia , new genus. Monogeneric.

COMMENTS: This new species, genus, and family is probably a noncyclorrhaphan eremoneuran, based on the lack of tibial spurs, the setiform empodium, 1-segmented cercus, and antennal flagellum with three articles. However, there is no evidence that Mysteromyia is an empidoid. Although the plumose “arista” is similar to certain acalyptrates, as in various ephydroids and Periscelididae , there is no doubt that this fly is not even a cyclorrhaphan, the convergence in wing venation with Phoridae notwithstanding. It lacks a lunule (this area of the head is very well preserved), and there are no macrosetae anywhere on the body, nor even sockets from dislodged setae. The apical two articles of the antennal flagellum are situated terminally (vs. dorsally) on flagellomere 1. Also, each branch of the plumose arista has a socket, indicating that each is probably a seta on the antennal stylus (in schizophorans a plumose arista has unsocketed, true branches). There are 10 welldefined abdominal tergites (vs. 8), albeit the terminal one highly reduced. The highly costalized wing venation has an overall similarity to that of Phoridae —but only superficially. Phoridae differ by the following: Sc is very short and usually incomplete, R 1 much shorter, R 2+3 either entirely fused to R 4+5 or separated only as a small apical fork (collectively, Rs); entire Rs usually very short, half or less of wing length; basal cells not configured as in Mysteromyia ; M and CuA veins readily apparent and even sclerotized; alula is small and commonly spinose. Clearly, costalization is convergent in the two families, and other than the loss of abdominal sternites there are no derived features in common.