Deep-water fauna from the Eocene flysch from Buje (Croatia)

Faunas from Eocene deep-sea methane-seep deposits from the flysch in Buje (Croatia) are described. They are composed chiefly of chemosymbiotic lucinid and thyasirid bivalves, families known already from the Cretaceous. Methane-seep deposits from Buje formed at conditions favourable also for vesicomyid and bathymodiolins known from some Eocene to Recent seeps, but these are lacking at Buje. However, both families occur in a few equivalent-aged seeps in the Pacific. We hypothesize that this is due to evolutionary antiquity of the deep-sea methane-seep faunas in the Tethys Ocean at that time.