Revision of the rudist genus Orestella Lupu, 1982 (Bivalvia, Order Hippuritida) from the Upper Cretaceous of Romania

Re-examination of the Orestella Lupu, 1982 (formerly Orestia Lupu, 1972) type material in the Geological Institute, Bucharest, Romania, revealed the need for revision of its taxonomic status. The holotype and paratypes of this taxon show the diagnostic characteristics of the Family Hippuritidae, not the Radiolitidae as previously indicated. This genus should therefore be transferred to the Hippuritidae. The structure of the pillars, the ligamental ridge and the outer shell layer of the right valve as illustrated by the type material point to an affiliation either with Hippurites or with Hippuritella. We discuss this assignment by taking into account the similarities with Hippurites organisans (de Montfort), Hippuritella lapeirousei Goldfuss and Hippuritella variabilis (Munier-Chalmas). The stratigraphic framework of the study material is also discussed with respect to the Upper Cretaceous successions in the Central-Eastern Carpathians of Romania.