Dr. Fűköh Levente szerk.: Malakológiai Tájékoztató 9. (Eger, 1990.)
Dávid Árpád: Paleontological observations on the shells of Lower-Bedenien
Dávid Árpád PALEOPATHOLOGICAL OBSERVATIONS ON THE SHELLS OF LOWER-BADENIAN GASTROPODS (Várpalota, Hungary) ABSTRACT : The most significant superficial outcrop of the Miocene, Lower-Badenian strata of the Várpalota-basin is the Szabó-bánya; (Szabó-mine). Its marine origin sandbeds contain molluscan fossils in exeptional richness. During the collection of the fossils of this area the author have found Terebra 1 i a bidentata (Eichwald) and Ptychopotamides papaveraceus (Basterot) tests with traces of fracture and recovery. In case of Terebralia bidentata (Eichwald) the fractures can be seen on the younger, thinner part of the spire. While on the shell of Ptychopotamidea papaveraceus (Basterot) the curvature refers to the fracture of the columella. We can also observe deformations, marks on the animals' remains that lived in the geohistorical past, which relate to damages, sicknesses. The investigation of the abnormal changesof the former living creatures is the subject of paleopathology. We can conclude the procès of illnes by reason of anomalies found on the findings: recovery happened eith enduring distortion, or damage caused the animal's death. Gastropod shells show paleopathological phenomena in great variety, too. (SZÓN0KY, M. 1978). The most noteworthy superficial exposure of the Miocene, Lower-Badenian strata of the Várpalota-basin in the Szabó-bánya; (Szabó-mine). (It is named after József Szabó, the famous Hungarian geolgist, who lived in the last century. The exposure is a natural consrevation area today). Its layers refer to a former shallow marine coastal region, and contain fossils abudantly (JUHÁSZ, Á. 1987). During the collecting from the outcrop's yellow-coloured friable sandstone, beside great number of other spacies, we have found tests of Terebralia bidentata (Eichwald) and Ptychopotamides papaveraceus (Basterot). Among these shells we could find two specimen with the trace of fracture and recovery (callus). These gastropods lived on the sea-bottom forming members of the benthonic biotope. They usually occured in groups, even in great messes and may have lived in a shallow-water, oxygen-rich, welltransilluminated , agitated enviroment. And could stand against the fluctuation of salinity. Seaweeds growing on the silty, fine-grained bottom served as nutriment for them (KÓKAY, I. 1971). The preservation and localization in the sandstonebed of the investigated shells show that the animals decay did not happen locally. These were eroded and broken up during the transportation. The streaming water caused that they got to the place where they were found. The damage of these slenderly built snails' shells was evidently the result of external impact. The fractures on the tests of these two animals presumably were owing to the percussion caused by currents or the surf. In case of Terebralia bidentata (Eichwald) the breaks can be observed on the thinner part of the spire; on the fifth, sixth and seventh whorls. The fractures on the sixth and seventh whorls are parallel with each other and cut the whorls across slantwise. (Fig. 1.) Seldom it may happen that due to the percussion the shell's central pillar (Columella) breaks, too. In this case it results in the twisting of the injured whorls, as a consequence of the dislocation. This phenomenon can be experienced on the shell of Ptychopotamides papaveraceus (Basterot) in our collection. On account of the fracture the columella distorted approximately at an angle of eight degrees. (Fig. 2.) On the side which is contrasted with the direction of twisting the suture, separating the eighth and ninth whorls broaden out significally .
