Taxonomy, phylogeny and biostratigraphy of the upper Aptian–lower Albian ammonites of the Chott area, southern Central Tunisia

International audienceFour sections were measured and studied in the uppermost Aptian and lower Albian of the Chott Basin (southern Central Tunisia), providing an abundant, bed-by-bed collected paleontological material. The ammonite succession allows precise correlations with the ammonite biozonation established in Central Tunisia. The phylogeny of knemiceratids and acanthohoplitinids of the Chott Basin is investigated and the alleged extreme variability of knemiceratids is questioned. Five new ammonite species are herein described: Knemiceras sagetae sp. nov., Knemiceras lanceolatum sp. nov., Knemiceras multicostatum sp. nov., Knemiceras tunisiense sp. nov., Parengonoceras chottensis sp. nov., highlighting the highly endemic character of the Chott Basin ammonite faunas