Kaszab Zoltán (szerk.): A Magyar Természettudományi Múzeum évkönyve 75. (Budapest 1983)

Vörös, A.: Some new genera of Brachiopoda from the Mediterranean Jurassic

The question whether they belong to Papodina or they form a closely related but new genus can be answered only after revealing their internal features. Papodina is ranged among the Cancellothyrididae because this family is characterized by the absence of the hinge plates and a similarly "primitive" loop, which originates from the socket ridges. The capillate ornamentation and the beak characters strengthen the affinity. On the other hand, it is impossible to find a subfamily within the Cancellothyrididae suitable for Papodina. The equivalent of the dorsally arched transverse band of Papodina can be found exclucively among the Eucalathinae. This subfamily, however, is known only from the Late Cretaceous to the Recent, moreover, its members are very minute forms rarely exceeding 10 m'" in length. fhe short, simple loop emerging from socket ridges without hinge plates appears in the family Pseudodielasmatidae (COOPER & GRANT 1976, p. 2910). These Permian genera are different externally and distant in time from Papodina but they might have been in ancestral relationship with it. Distribution : Sinemurian and Pliensbachian of the Northern Limestone Alps and Hungary. Suborder TE REB RATELLID IN A MUIR-WOOD. 1955 Superfamily Zeilleriacea ALLAN. 1940 Family Zeilleriidae ALLAN. 1940 Genus Bakonyithyris gen. n. Derivatio nominis: after the name of the Bakony Mts. (Hungary) Type species: B. pedemontana (PARONA, 1893) Diagnosis : Small terebratellids, subpentagonal to rounded in outline, biconvex posteriorly, concavo-convex (sulcate) anteriorly. Beak incurved, beak ridges sharp. Dental plates parallel: septalium V-shaped, median septum short and low. Crural processes incurved, loop short, spinose anteriorly, ascending branch expanded, hood-like. Description : External characters (Representative figures of the type species: PARONA 1893. pl. II, fig. 26a-b; BÖSE & SCHLOSSER 1900, pl. XVII, figs 21, 21a-c, 24a-c, under the name "Waldheimia ampezzand

1

''): Bakonyithyris consists of a series of small, sulcate terebratellids with subpentagonal to rounded outline. The valves are nearly equally convex posteriorly. At the midlength of the brachial valve a shallow sulcus develops becoming wider and deeper anteriorly. The pedicle valve is practically evenly convex without median carina. The lateral commissures are gently arched ventrally. the anterior commissure is widely sulcate. The surface is smooth with faint growth lines. The beak is small, pointed, incurved; the beak ridges are sharp. The foramen is very small, mesothyridid. The deltidial plates are disjunct. Internal characters (Figs 17, 18) — Pedicle valve: The delthyrial cavity is subquadrate to hexagonal; the umbonal cavities are trigonal in cross-section. The dental plates are long and subparallel. No pedicle collar has been observed. The hinge-teeth are short and simple. Denticula are poorly developed. — Brachial valve (Fig. 20): There is no cardinal process but a narrow, deep muscle-trough is developed. This continues in a deep, V-shaped septalium formed by the fused inner hinge plates (septalial plates). The septalium is supported by a strong but short median septum not attaining onethird of the valve length. The septalium disappears at about the plane of articulation and in this way the edge of the median septum and the crural bases become free from each other. The crural bases remain attached to the narrow and dorsally curved outer hinge plates. The outer hinge plates lie in the continuation of the elevated inner socket ridges which, in turn, lean over the sockets. The crura are given off dorsally; the crural processes are incurved. The descending branches are thin and narrow; the ascending branches are wide, expanded with hood-like transverse band. Spinosity was observed only on the anterior end of the loop. Species: B. ewaldi(OPPEL) (1861. p. 539. pl. XI, fig. la-c). — B. apenninica (ZITTEL) (1869. p. 127, pl. XIV. fig. 9a-d). — ? B. meneghinii (PARONA) (1880, p. 194, pl. I, fig. 5a-c). — B. pedemontana (PARONA) (1893, p. 49, pl. II. fig. 26a-b). — B. ovimontana (BÖSE) (1898. p. 178, pl. XIII, fig. 11,12).