Szekessy Vilmos (szerk.): A Magyar Természettudományi Múzeum évkönyve 62. (Budapest 1970)

Nagy, I. Z.: Lower Liassic molluscs from the Mts. Mecsek, Hungary

Lima (Plagiostoma) exaltata TERQUEM PL II, Fig. 5. Examined material: Mold fragments, partially with shells. Szabolcs, Ferenc shall; Szabolcs, bed 8; Pécsbányatelep, András shaft, cover of bed 4. M 69.346; M 69.354. Remarks: The shells are covered with fine and even costae, slightly sinuous in the direction of growth. They are also interrupted and separated by the robust growth lines. On the younger part of the shell, the intercostal areas are filled with a beaded sculpture. According to another description (e.g. GOLDFUSS, p. 76, PI. 101, Fig. 26), the costae themselves are formed by these beads. However, the illustration fails to demonstrate that the costae consist of such rows of beads. On the other hand, Lima compressa TERQUEM does show this sculpture and may hence be a synonym of L. punctata SOWERRY. Superfam.: Ostreacea; Fam.: Ostreidae LAMARCK, 1818; Genus: Liostrea DouVILLÉ, 1904. Liostrea irregularis (MÜNSTER) Plate I, Fig. 8; Plate II, Fig. 1. Examined material: Molds and shell fragments. Komló, Kossuth shaft; Hosszuhetény, shale dump M 69.363. Remarks: SCHÄFLE'S list of synonyms (1929, p. 16-17) illustrates most convincingly the taxonomic difficulties deriving from shell morphology. Our species appears to be frequent in the Liassic of the Mts. Mecsek, locally forming also thick beds. Adnate specimens frequently occur on plant fossils (Pl. I, Fig. 8). The size and shape of the shells are highly variable; they are smooth, with the occasional appearance of growth lines. The margin of the shell is slightly involute. Subfam. : Gryphaeinae VIALOV, 1936; Genus Gryphaea LAMARCK, 1801. Gryphaea obliqua GOLDFUSS Pl. II, Figs. 2-4. Examined material: Fragments of 8 specimens, partially with shells. Pécsbányatelep (M 57.3710), and Komló, Kossuth shaft, level 4 (M 69.342). Flanging marl over coal beds. Remarks: By their sculpture and habit, the specimens are easily identifiable. Both the adnate and the closing shells are present. In spite of the fact that an exact identification is possible only by mass examinations, the "species" can be distinguished by the state of spirality. Without adding to the rich stratigraphie— phylogenetic literature of the " Gryphaea-pvoblem"

, I assign the specimens from the Mts. Mecsek to the Formenkreis of the above "species". (Later investigations might prove that this taxon represents but a developmental stage of G. arcuata). The forms from the Mts. Mecsek are slightly flattened and thus resembling Gr. cymbium. Superfam.: Mytilacea; Fam.: Rfytilidae FLEMING, 1828; Genus: Modiola LAMARCK, 1801.