The Albian-Cenomanian transition in a shelf-basin transect: Biostratigraphy, sedimentology and paleontology of Jebel Mghila, Central Tunisia

Twenty-two ammonite species are identified in the upper Albian Mortoniceras ( Subschloenbachia ) rostratum , perinflatum and Stoliczkaia Shumarinaia africana Zones, lower Cenomanian Mantelliceras mantelli Zone. The Placenticeras Saadensis Thomas (Thomas Peron, 1890, 1890 is revised, including Engonoceras Thomasi Pervinquière, 1907, placed within genus Hypengonoceras Spath, 1922. This accurate biostratigraphic framework allowed to evidence, at Albian-Cenomanian transition S. (S.) Zone), a significant sea level drop, responsible for emergence erosion SE, deposition of Lowstand wedge NW, fed by erosional channels on shelf slope. Plesiosaur remains found series (base M. Zone) represent one few elasmosaurids known worldwide Albian, first plesiosaurian reported from Tunisia.