Verbreitung von Chondrichthyes-Arten (Vertebrata, Pisces) im Rupelium des Mainzer Beckens und im Chattium von Norddeutschland

The author presents a preliminary list of Chondrichthyes species from the Rupelian deposits of the Mayence Basin and from Chattian deposits in northern Germany, based on literature data and on newly collected material. The lower number of species, compared to Eocene and Miocene faunas, suggests either a decrease in temperature during the Oligocene, or a paleogeographical isolation of the area considered. Because of the improbability of the latter possibility and because of the fact that southern elements are absent in the faunas a temperature drop is more probable.