Observation of the elusive bone-skipper fly Centrophlebomyia furcata (Fabricius, 1794) at least 128 years after its last record in France, and additional data on Thyreophora cynophila (Panzer, 1794) in France (Diptera: Piophilidae)

Once thought to be extinct species, the necrophagous flies Centrophlebomyia furcata and Thyreophora cynophila are iconic representatives of the western Europe dipterofauna. They are extraordinary insects active during the winter season and associated with the carcasses of large mammals. After the discovery of T. cynophila in Ariege in 2020 and the confirmation of its extended presence in the Pyrenees Mountain range, a search for C. furcata was initiated. During a visit to nine vulture feeding stations in the Pyrenees and Corbieres mountain ranges, adults of C. furcata were collected in two of them, in the northern Basque country (Pyrenees-Atlantiques department, France). This is the first precisely documented observation of C. furcata in France. The rediscovery of C. furcata and T. cynophila in the Pyrenees Mountain range raises the question of their presence elsewhere in France and Europe, notably in other mountain ranges. An updated map of the distribution area of both species is provided. We also raise concerns about the maintenance of vulture feeding stations to avoid detrimental impacts on those rare necrophagous insects and consider forensic issues.