Vörös A. szerk.: Fragmenta Mineralogica Et Palaentologica 15. 1992. (Budapest, 1992)

Germany, Switzerland, the Eastern Alps (Hierlatz, Vilser Alps), the Southern Alps (South Tyrol, Lugano, Venetian Alps), Sicily (Taormina), the Gerecse Mountains, and the Bakony Mountains. Genus Prionorhynchia BUCKMAN, 1918 Prionorhynchia greppini (OPPEL, 1861) (Pl. I, Fig. 4; Text-fig. 6) 1861 Rhynchonella greppini n.sp. - Oppel: p. 545, pi. 12, figs. 1-2. 1884 Rhynchonella greppini OPPEL - Haas: p. 13, pl. 1, fig. 2., pi. 2, fig. 8. 1889 Rhynchonella greppini OPPEL - Geyer: p. 48, pi. 6, figs. 1-9. 1893 Rhynchonella greppini OPPEL - Parona: p. 37, pi. 2, fig. 11. ?1900 Rhynchonella greppini OPPEL - Böse and Schlosser: p. 194, pi. 18, figs. 12-14. 1953 Rhynchonella greppini OPPEL - Rossi Ronchetti and Brena: p. 124, pi. 11, fig. 7. non 1884 Rhynchonella greppini OPPEL - Haas: p. 13, pi. 2, fig. 3. Material: 1 complete and 3 incomplete specimens. Dimensions (mm): Specimen M.91.07. (Text-fig. 6) length: 11.5, width: 15.0, thickness: 8.0. Text-fig. 6 - Drawing of Prionorhynchia greppini Description - External characters: Mediumsized shell, subtriangular in outline. The sides of triangle are straight, the base is convex. The angle between the lateral margins is about 90°. The antero-lateral corners are very rounded. The width is greater than the length while the thickness is two-thirds of the length. Biconvex form, the valves are equally convex. The maximum width is situated at the anterior third while the maximum convexity is at the posterior third. The beak is small and erect. The long and slightly depressed planareas are well demarcated by strong beak ridges on both valves. The lateral commissures are straight and run in the middle of planareas. The anterior commissure is straight or slightly uniplicate showing zigzag deflections. The shell surface is costate, on each valve 8 to 10 sharp costae run straight to the anterior end without bifurcation. The cross-section of costae is high triangular. There is a weak capillation on the surface of planareas. Internal characters: There were no adequate specimens available for serial sectioning due to the paucity of the material. Remarks: Haa's specimen (1884, pi. 2, fig. 3) is misidentified as it is more densely ribbed than Prionorhynchia greppini. Böse and Schlosser's (1900) determination is questionable since the rib profile of their specimen is much lower than what is typical of P. greppini. P. greppini differs from the otherwise similar P. polyptycha by its less dense costation and slimmer appearance. Oppel (1861) and Geyer (1889) distinguished the two species on the basis of concavity of planareas. However, this feature is very variable on both species. Oppel (1861) described Rhynchonella palmata as a subspecies of P. greppini. It was later proved to be a distinct species (Uhlig 1879).