The male abdominal, genital and pregenital sclerites and musculature in Neria commutata (Czerny, 1930) (Diptera, Micropezidae)

Abstract

The muscles of the male abdomen and genitalia of Micropezidae were studied for the first time by the example of Neria commutata (Czerny, 1930). Based on analysis of the sclerites and musculature of the male genitalia of Micropezidae as compared to those of the previously studied Acalyptratae and Aschiza, we revealed several apomorphies of this group. The hypandrial complex is characterized by the presence of the phallic retractors and protractors M1 and M2, and the epandrial complex, by the presence of muscles M3 of the subepandrial sclerite, muscles M4 of the surstyli, muscles M7 of the cerci, and also the tergosternal muscles M5; all these muscles correspond to the ground plan of Cyclorrhapha. The following characters are considered apomorphic: the splitting of intersegmental sternal muscles ISM5–6 into 4 pairs that ensure the functioning of the forcipate appendages of sternite V; development of syntergosternite VII and reduction of muscles ISM6–7; the splitting of muscles M3 of the subepandrial sclerite into 4 pairs, enhancing the function of this sclerite; the appearance of pregonites with the associated muscles M42, which probably occurred independently several times in the evolution of different groups of Cyclorrhapha; asymmetry of syntergosternites VII and VIII and their muscles. The sclerites and muscles of the epandrium and hypandrium are characterized by complete symmetry.