Two look-alike dasycladalean algae: Clypeina isabellae masse, Bucur, Virgone & Delmasso, 1999 from the Berriasian of Sardinia (Italy) and Clypeina loferensis sp. N. from the upper Jurassic of the Northern Calcareous Alps (Austria)

New material from the Berriasian of eastern Sardinia, Italy, and from the NW of Sardinia published by PECORINI in 1972 as 'Clypeina sp. A', allows a better characterization and an emended diagnosis of Clypeina isabellae MASSE et al., 1999 from the Berriasian of SW France. Another morphologically somehow similar Clypeina species from the Upper Jurassic of the Northern Calcareous Alps of Austria is described as Clypeina loferensis n. sp. Remarks on the genera Clypeina MICHELIN and Hamulusella ELLIOTT, a Clypeina-type dasycladalean alga with proximal bulged laterals, and Clypeina jurassica-sulcata are also provided.