Iceland, a mere remote island or a hoverfly (Diptera, Syrphidae) hotspot for endemism? A case study of Platycheirus islandicus Ringdahl, 1930 and P. manicatus Meigen, 1822

Abstract

During a short expedition in 2021 several individuals of Platycheirus Meigen, 1822 were collected, both as dry material and in alcohol. Among this material we found a single Platycheirus species of the manicatus subgroup and another species belonging to the peltatus subgroup. The molecular and morphological data suggest the presence of Platycheirus islandicus Ringdahl, 1930 as a non-migratory endemic species for Iceland and Platycheirus manicatus Meigen, 1822 as a migratory species with regular influx from mainland Europe. The DNA barcodes as well as morphological characters are given for both species. A discussion about colonisation, and related topics like the nunatak and tabula rasa hypotheses, and migration theory on the endemism in Iceland is given.