Resolving the Taxonomy of Mountain Syrphidae (Diptera) in the Iberian Peninsula: The Species Group of Cheilosia melanura Becker, 1894.

Simple Summary: Hoverflies are a diverse group of dipterans (6800+ species worldwide) of high relevance to pollination and the regulation of insect pest populations. With nearly 500 described species worldwide, Cheilosia represents the largest hoverfly genus in the Palaearctic, with larvae of most species feeding on flowering plants or fungal tissues. The complexity of this genus is eased by the definition of various species groups, including the group of Cheilosia melanura, which is assessed in this paper in the context of the Iberian Peninsula. The aim of the present work is to improve the knowledge of this species group by following an integrative approach, i.e., a combined use of different data sources (e.g., morphology and genetics) to solve a taxonomic problem or evaluate a taxonomic scenario. With this approach, we found and described a species new to science from Spain and provided the first identification key for all Iberian species of the group, including most of the European species. The largest genus of Palaearctic Syrphidae, Cheilosia Meigen, 1822 (Syrphidae: Rhingiini), is currently under revision in the Ibero-Balearic region (Iberian Peninsula + Balearic Islands). Prior to this study, various species groups with putative phylogenetic support were defined for this genus of complex taxonomy. The group of Cheilosia melanura Becker, 1894 includes species distributed all over Europe, with some of these species being similar each other in both morphology and genetics. After recent fieldwork in different Iberian localities and consultation of entomological collections, a new species from Sierra Nevada (Granada, Spain) was uncovered, described, and illustrated. Data on diagnostic characters, intraspecific variability, and adult biology were also provided. Maximum likelihood analyses of the fragment "C" of the 5′ end of the cytochrome c oxydase subunit I (COI-5′) and complete COI-5′ were performed to explore and support morphological species concepts within the group. The Spanish-endemic Cheilosia andalusiaca Torp Pedersen, 1971 is recognised here to be part of the C. melanura group based both on morphological and molecular evidence. Cheilosia carbonaria Egger, 1860 and Cheilosia cynocephala Loew, 1840 from the Iberian Peninsula are reported for the first time based on specimens originating in the Spanish Pyrenees. An identification key for the Iberian species of the C. melanura group is provided. [ABSTRACT FROM AUTHOR]