Melanostoma mellinum (Linnaeus, 1758)

Heimburg, Helge, Doczkal, Dieter & Holzinger, Werner E., 2022, A checklist of the hoverflies (Diptera: Syrphidae) of Austria, Zootaxa 5115 (2), pp. 151-209 : 171

Melanostoma mellinum (Linnaeus, 1758)

The long-standing concept of three species of Melanostoma in Europe has been challenged by Haarto & Ståhls (2014) who used an integrated approach (morphology of adults in combination with ITS2 sequences) to revise the North-European species. The morphologically highly variable M. mellinum turned out to contain two species, M. mellinum and M. mellarium (Meigen, 1822) . We identify our material from Central Europe using the key in Haarto & Ståhls (2014) as well as the keys in Speight & Sarthou (2017) and in Bot & van de Meutter (2019). In accordance with Speight & Sarthou (2017) we found specimens which completely fit the diagnosis of M. mellarium . However, the range of morphological variation within the M. mellinum complex in Central European populations is apparently much wider than in the material studied by Haarto & Ståhls (2014), as a large part of our material does not fit unambiguously to any of these taxa. In particular, populations from the Alps and adjacent regions display confusing variation indicating that additional species could be involved. A detailed investigation of multiple characters including DNA markers are required to disentangle the complicated taxonomy of central European Melanostoma . At present, we regard the species of the M. mellinum complex as unidentifiable, at least as far as populations from the Central European Alps are concerned. Consequently, we refrain from listing taxa other than those known prior to Haarto & Ståhls (2014).