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

Genus Bakonyithyris VÖRÖS, 1983 Bakonyithyris ewaldi (OPPEL, 1861) (Pl. VI, Fig. 3; Text-fig. 40) 1861 Terebratula (Waldheimia) Ewaldi n.sp. - Oppel: p. 539, pl. 11, fig. 1. 1874 Waldheimia Ewaldi OPPEL - Gemmellaro: p. 69, pl. 11, figs. 7-8. 1880 Waldheimia cfr. Ewaldi OPPEL - Parona: p. 200, pl. 2, fig. 3. 1889 Waldheimia Ewaldi OPPEL - Geyer: p. 31, pl. 4, figs. 3-7. 1895 Waldheimia cfr. Ewaldi OPPEL - Fucini: p. 214, pi. 24, fig. 2. 71924 Waldheimia (Aulacothyris) Ewaldi OPPEL - Maugeri-Patané: p. 35, pl. 1, figs. 15-16. 1964 Zeilleria ewaldi OPPEL - Sacchi Vialli: p. 18, pi. 3, fig. 12. 1964 Zeilleria ewaldi OPPEL - Siblik: p. 167, pi. 7, fig. 4. Material: 1 poorly preserved specimen. Dimensions (mm): Specimen M.91.34. (Text-fig. 40) length: 13.5, width: 13.4, thickness: 7.4. Description - External characters: Medium/•w^ sized shell, subpentagonal in outline. The anteroV^w^ lateral corners are rounded. The angle between the lateral margins is about 75°. The width is equal to the length while the thickness is hardly Text-fig. 40 - Drawing of greater than half of the length. Biconvex form, Bakonyithyris ewaldi tne valves are equally convex. The maximum width is situated at half of the length, the maximum convexity is at the posterior third. The beak is small and erect. There are two strong beak ridges on the pedicle valve. The lateral commissures are not visible due to the poor preservation. The anterior commissure is sulcate. The depth of sulcus is half of the total thickness. The sulcus develops from two-thirds of the length on the brachial valve. The sulcus is V-shaped in cross-section at the anterior margin. The shell surface is smooth. Internal characters: The internal character remains unknown as only one specimen of this species was found, so there was no possibility for serial sectioning. Remarks: In spite of the poor preservation this species can be easily separated from the similar forms on the basis of its distinctive V-shaped sulcus. Distribution: According to Aimeras (1964), Bakonyithyris ewaldi is Sinemurian in age. The occurrence of this species in the Pliensbachian is uncertain. The species was reported from the Eastern Alps (Hierlatz), the Southern Alps (Piemonte, Sal trio), Sicily (Trapani), the Western Carpathians and the Bakony Mountains.