Obscuromyia, a remarkable new genus of the endemic Australian tribe Myiotrixini (Diptera : Tachinidae : Tachininae)

Abstract

The endemic Australian tribe Myiotrixini is reviewed and a new genus andspecies described. The monotypic genus Myiotrixa Brauer & Bergenstamm, 1893, is known from all States except the NorthernTerritory, but has been most frequently collected from south-easternAustralia; the single species, M. prosopina, is aparasite of the native Australian cockroachPlatyzosteria castanea Brunner.Obscuromyia, a new monotypic genus of Myiotrixini fromnorthern Western Australia, is described and the relationship between it andMyiotrixa discussed. Striking synapomorphies of the maleand female terminalia corroborate the sister-group relationship betweenObscuromyia and Myiotrixa. These synapomorphies are the medially fused pregonites which encircle the base ofthe aedeagal apodeme in the male, and in the female the lack of sclerotisedsternites in most of the abdomen and ovipositor, and the non-extensible andnon-piercing ovipositor in which segment 8 forms a sclerotised cylinderincised dorsally and ventrally. A revised diagnosis of the Myiotrixini isprovided along with a diagnostic key to the two genera.