Discovery of a Lineage of Soil-Dwelling Medetera Species with Multi-Coloured Eyes in Southern Europe (Diptera: Dolichopodidae)

SIMPLE SUMMARY: Long-legged flies or Dolichopodidae are one of the most speciose fly families of the order Diptera. At present, dolichopodid faunas in the tropics still encompass a large undescribed fraction, but in Europe new species can also be found. Recently, two new species of Medetera with a conspicuous eye colour pattern were discovered in Portuguese samples. Increased subsequent collecting efforts in southwestern Europe added another five species, most of which also featured a distinct eye colour pattern. All seven species are described in this paper with information on their distribution and ecology. An identification key to males is also provided. All these species share genital and some non-genital characters which suggests that they belong to the same lineage within this genus. Barcoding data seem to confirm this, as does the ecological information. Indeed, contrary to many Medetera species which are confined to tree trunks where their larvae feed on all stages of bark beetles, several of the new species are mainly found on hard, often rocky, substrates also in open habitats. ABSTRACT: Seven species in the genus Medetera (Diptera: Dolichopodidae) are described here: Medetera aglaops sp. nov., Medetera corsicana sp. nov., Medetera gibbosipyga sp. nov., Medetera hispanica sp. nov., Medetera lusitana sp. nov., Medetera parva sp. nov., and Medetera rectipyga sp. nov. They all originate from the wider Mediterranean region in southwestern Europe (Iberian Peninsula, southern France, Corsica, Sardinia). The most striking feature in most of the species is the bi- or multicolour pattern of the eyes, most conspicuous in Medetera aglaops sp. nov. and Medetera lusitana sp. nov. This character is shared by the male and female sex and is thus not regarded as Male Secondary Sexual Character. All species belong to the Medetera apicalis species group sensu Bickel and are closely related based on shared characters in the hypandrium and cercus. Interestingly, three species with and four species without the basal pair of anterodorsal and posterodorsal bristles on the mid tibia are represented. This suggests that this diagnostic character has less phylogenetic relevance than previously anticipated. Unlike most Palaearctic Medetera, at least five of the new species are mostly found on rocky substrates in dry biotopes with a sclerophyllous vegetation. This further supports their relationship with species of the Medetera muralis subclade sensu Pollet, Germann and Bernasconi.