On the enigmatic Sinonemestrius Hong & Wang, 1990, with description of a new species based on a complete fossil fly (Diptera, Brachycera, Tabanomorpha, Heterostomidae)

Abstract

A new species of Sinonemestrius Hong & Wang, 1990 is described and illustrated based on a complete compression fossil of the fly. Currently placed in Rhagionemestriidae or Xylophagidae, the present study concludes that the morphology of the new find indicates that Sinonemestrius is a heterostomid genus within Tabanomorpha. The placement of Ahirmoneura neimengguensis K-y Zhang et al., 2008 is reassessed. It demonstrates close similarities in body structure and wing venation to those of Sinonemestrius, and can be provisionally transferred from Nemestrinidae to Heterostomidae: Sinonemestriinae.