Matskási István (szerk.): A Magyar Természettudományi Múzeum évkönyve 88. (Budapest 1996)

Dulai, A.: Taxonomic composition and palaeoecological features of the Early Badenian (Middle Miocene) bivalve fauna of Szob (Börzsöny Mts, Hungary)

The fauna is highly dominated by suspension feeders because the organic matter is very rapidly decayed due to the high oxygen content of the sea-water inside the seagrass meadows, therefore the bottom sediment was very poor in organic matter (HOFFMAN et al. 1978). Bivalves refer to infralittoral depth in the photic zone. The soft, mixed, sandymuddy bottom was fixed by the roots of seagrass. The old museum collection contains more species, but the proportion of the species is anomalous at the most frequent bivalves, because the collectors keep in view only the diversity of the fauna and not the frequency of certain species. For this reason the museum collection is very good for the examination of palaeodiversity or taxonomy, but the above bias must be kept in mind in the case of palaeoecological studies based on the museum collections. Acknowledgments - This study was supported by the Hungarian Scientific Research Fund (OTKA F 13975). Many thanks arc due to Dr MARGIT BOHN-HAVAS for the useful discussions on molluscs. I thank Dr ATTILA VÖRÖS for his advice and reviewing the first version of my paper. REFERENCES BÁLDI, T. (1962): Glycymeris s. str. des europäischen Oligozäns und Miozäns. - Annls hist.-nat. Mus. natu, hung. 54:85-153. BÁLDI, T. (1973): Mollusc fauna of the Hungarian Upper Oligocène (Egerian). - Akadémiai Kiadó, Budapest, 511pp. BÁLDI, T. & KÓKAY, J. (1970): A kismarosi tufit faunája és a börzsönyi andezitvulkánosság kora. (Die Tuffîtfauna von Kismaros and das Alter des Börzsönyei- Andesitvulkanismus). - Földt. Közi. 100: 274-284. BENIGNI, C & ROBBA, E. (1990): A Pliocene Micromorph Brachiopod-Pectinid Community. - In: ROBBA, E. (ed.): Proc. 4th Symp. Ecol. Palaeoecol. Benthic Communities, Mus. Reg. Sei. Nat. Torino, pp. 341-356. BERNASCONI, M. P. & ROBBA, E. (1993): Molluscan palaeoecology and sedimentological features: an integrated approach from the Miocene Meduna section, northern Italy. - Palaeogeogr. Palaeoclimatol. Palaeoecol. 100: 267-290. BOHN-HAVAS, M. (1973): A Keleti-Mecsek torton Mollusca faunája. (Tortonische Molluskenfauna des Östlichen Mecsek-Gebirges). -Ann. Inst. Geol. Puhl. Hung. 53 (4): 945-1140. BOSENCE, D. W. J. (1979): Live and dead faunas from coralline algal gravels, Co. Galway. - Palaeontology 22 (2): 449-478. BRASIER, M. D. ( 1975): An outline of seagrass communities. - Palaeontology 18 (4): 681-702. CSEPREGHY-MEZNERICS, I. (1950): A hidasi (Baranya m.) tortonai fauna. (Die Tortonische Fauna von Hidas (Kom. Baranya, Ungarn)). -Ann. Inst. Geol. Puhl. Hung. 39 (2): 1-115. CSEPREGHY-MEZNERICS, I. (1952): Paläontologische Seltenheiten in der Fauna von Szob. - Annls hist.-nat. Mus. natu. hung, (s.n.) 2: 225-231. CSEPREGHY-MEZNERICS, I. (1953): Miltelmiozäne Pleurotomen aus Ungarn. - Annls hist.-nat. Mus. natu. hung. (s.n.) 4: 5-22. CSEPREGHY-MEZNERICS, I. (1956): A szobi és letkési puhatestű fauna. (Die Molluskenfauna von Szob und Letkés).- Ann. Inst. Geol. Publ. Hung. 45 (2): 361-448. DAVITASHVILI, L. S. & MERKLIN, R. L. (1966): Spravocnik po ekologii morskih dvustvorok. - Nauka, Moskow, 352 pp.