Cenomanian radiolitid bivalves from Malchina, Karst of Trieste, Italy

A radiolitid fauna, rudist bivalves, composed of Durania acuticostata Caffau and Pleničar, Eoradiolites fleuriausus (d’Orbigny), Eoradiolites liratus (Conrad), Paronaites zuffardii (Parona), and Sauvagesia sharpei (Bayle) is described from the upper Cenomanian Monrupino Formation in the Malchina area, Karst of Trieste. The taxonomic part includes [1] the proposal of the new genus Paronaites and [2] neotypes for E. liratus, [3] the identification of several junior synonyms (Eoradiolites zucchii Caffau and Pleničar and Praeradiolites acutilamellosus Caffau and Pleničar for E. fleuriausus; Eoradiolites zizensis Astre and Eoradiolites adriaticus Caffau and Pleničar for E. liratus; and Eoradiolites carsicus Caffau and Pleničar for P. zuffardii), [4] the discrimination between E. liratus and Eoradiolites schweinfurthi Zittel, and [5] the identification in Europe of species so far only reported in North Africa, besides [6] illustrating the diagnostic characters and morphologic variability of the treated species. All this facilitates their proper identification and certainly helps the stratigraphic correlation of the Cenomanian shallow water carbonates deposited on the margins of the Tethys.

► Identification of junior synonyms simplifies late Cenomanian radiolitids taxonomy.
► Radiolitids correlation value improved because identified at Tethys both margins.
► Paronaites has Radiolites type outer shell layer structure and Eoradiolites type radial structures.
► Lebanon Parona’s (1921) specimens chosen as neotypes of Eoradiolites liratus (Conrad).
► Eoradiolites schweinfurthi (Zittel) is a different species from E. liratus (Conrad).