Winnertzia Rondani 1860

Genus Winnertzia Rondani, 1860 With more than 130 species named globally, Winnertzia ranks among the three largest genera of mycophagous cecidomyiids (Gagné & Jaschhof 2021). It was recently shown regarding Winnertzia in Sweden that a large proportion of the intrageneric diversity remains to be discovered and described, even in regions where the genus has been studied before (Jaschhof & Jaschhof 2020b). As a consequence, Winnertzia was estimated to have 300‒400 species in Europe, i.e., four to five times as many as have been named from this continent in the past (Jaschhof & Jaschhof 2020b). The results obtained here confirm this estimate. While prior to the present project only six species had been documented in the literature (including W. globifera Mamaev, 1963 agg.), there is now evidence of more than 109 different Winnertzia occurring in Germany, of which 43 can be named (incl. W. bulbifera Mamaev, 1963 agg., W. discretella Spungis, 1992 agg., W. solidaginis Felt, 1907 agg., W. xylostei Mamaev, 1963 agg., and four new species). The 66 species left unnamed here are either new to science (presumably constituting the majority) or cannot be recognized by means of descriptions available from the literature. Jaschhof & Jaschhof (2020b) discussed in detail the enormous challenges that taxonomists face when attempting to subject Winnertzia in Europe to a comprehensive revision. With such a revision pending, several of the species treatments below should be understood as describing merely the present state of research rather than ultimate knowledge.