The turtles from the upper Eocene, Osona County (Ebro Basin, Catalonia, Spain): new material and its faunistic and environmental context

摘要

Eochelone voltregana n. sp. is a new marine cryptodiran cheloniid found at the Priabonian levels (latest Eocene) of the Vespella marls member of the Vic-Manlleu marls formation. It is the second cheloniid from Santa Cecilia de Voltrega (Osona County, Spain), the first one being Osonachelus decorata from the same formation. Shell parameters indicate that the new species belongs to a branch of sea turtles including the Eocene Anglo-Franco-Belgian forms Argillochelys, Puppigerus and Eochelone (the shell of the latter was studied here for the first time) as well as Glarichelys from the Oligocene of Switzerland, all of them predating the worldwide living Miocene genera. The description of two other more littoral-continental Eocene species is given: Trionyx sp., from an older layer of the same formation; and the podocnemidid erymnochelyine, Cordichelys from a more basal layer of a middle Eocene (Lutetian) formation. The last one is identified as the only evidence of the Shweboemys subgroup in the European record, being distinct from the other known Osona County pleurodire Eocenochelus farresi, which is a member of the Erymnochelys group (same subfamily), from the younger Priabonian Sant Marti Xic layer. Thus, an update on the marine turtle fauna of the eastern Ebro Basin that variably opened in the east during Eocene times is provided. The turtles of Osona County belong to two suborders and five genera with three new species and extend the known distribution of their families (LSID urn:lsid:zoobank.org:act:48CE8676-7B82-4EF2-8165-27BEE90129F2).