Cretaceous fish assemblages in north-eastern Mexico: a case-study for actinopterygian diversification and global paleobiogeography

Recent palaeontological fieldwork unearthed a plethora of platy limestone deposits in north-eastern Mexico, which yields exceptionally preserved fossil fishes of Cretaceous age. During the project, which is supported by the German Research Foundation, we determined and dated a lot of findings of unknown fish species together with species known already outside from Mexico. These data provide new insight in the temporal and spatial distribution of fishes during the Cretaceous. We assess the changes in assemblage compositions through time in order to detect origin, migration and extinction of single taxa. First results show that major environmental changes during the “Mid-” Cretaceous provoked migration and extinction within the assemblages leading to several strong faunal turnovers within a short period. Depleted faunas in the Gulf of Mexico were subsequently supplemented by taxa originating eastwards in the Central Tethys. During the early Late Cretaceous, these taxa dispersed westwards following the ocean currents. The aim of the project is a documentation of the Cretaceous faunal turnover of the fish assemblages and its connection with major climatic and oceanographic changes. Results of the project could help to appraise future perspectives of recent fish faunas.

PhD student: Samuel Giersch
PIs: Prof. Dr. Wolfgang Stinnesbeck, Universität Heidelberg, apl Prof. Dr. Eberhard „Dino“ Frey, SMNK, financial support: DFG