Original paper

Resolving the Monte di Cetona biostratigraphical enigma - a revision of R. Fischer's Sinemurian and Pliensbachian (Liassic) ammonite collection from the Central Appenines (Tuscany, Italy)

Blau, Joachim; Meister, Christian

Abstract

The revision of Fischer's (1970, 1971) ammonite collection from the Murate section (Monte di Cetona, Tuscany, Italy) allows to precise the systematics and the biostratigraphy of this area. In his works Fischer (1970, 1971) attributed many classical Lower Pliensbachian species to the Upper Sinemurian, thus confusing the specialists of the Mediterranean ammonite's biostratigraphy. Unfortunately, Fischer only figured the ammonites now placed in the subfamily Reynesocoeloceratinae. In the present paper we describe 32 taxa systematically. From a biostratigraphical point of view a sequence of 6 faunal horizons indicating the Obtusum, Jamesoni, Ibex and Davoei zones is established. This sequence is well comparable to already published data from other Tethyan localities. With our revision the systematic and biostratigraphic enigmas resulting from Fischer's studies are solved.

Keywords

ammoniteslower jurassicsinemurianpliensbachianmonte di cetonaapenninesitaly