The shark and ray teeth of the Lower Miocene (Upper Marine Molasse) from Ballendorf, Baden-Württemberg, Southern Germany

Abstract

AbstractIn an abandoned sand pit near Ballendorf (Alb-Donau District, Baden-Württemberg), sediments of the Upper Marine Molasse (Lower Miocene) are present. In these sediments, 39 shark and ray species belonging to 29 genera were identified (Aetobatus, Alopias, Araloselachus, Carcharhinus, Carcharias, Centrophorus, Chaenogaleus, Dasyatis, Galeocerdo, Hemipristis, Iago, Isistius, Keasius, Notorynchus, Pachyscyllium, Paragaleus, Physogaleus, Pristiophorus, Raja, Rhinobatos, Rhinoptera, Rhizoprionodon, Rhynchobatus, Scyliorhinus, Sphyrna, Squalus, Squatina, Taeniurops, Triakis). However, in this paper we only illustrate and describe the 23 taxa not already discussed in previous publications on the Upper Marine Molasse deposits of Äpfingen, Rengetsweiler and Ursendorf, apart from two exceptions: teeth from jaw positions not previously illustrated, and specimens that are better preserved than those in previous publications. Specimens only determined as “sp.” were illustrated because it cannot be ruled out that they represent different species to the ones published earlier. Nearly all of the taxa found have Recent relatives; only Araloselachus, Keasius and Physogaleus are extinct. Most of the recovered taxa lived on or near the bottom in the shelf region. Alopias and possibly also Keasius lived higher in the water column. With Isistius, a taxon living in the oceanic realm was present, and the Recent representatives of Centrophorus live in deeper waters. Nearly all taxa fed on invertebrates and/or fishes; Isistius also fed as an ectoparasite. Additionally, two generalist feeders (Galeocerdo, Notorynchus) and one filter feeder (Keasius) were identified. The species Carcharias crassidens, which is not common in the Upper Marine Molasse, was also verified. Other fossils found in this deposit include remnants of odontocete cetaceans, molluscs, balanid barnacles, algae, and teeth of terrestrial mammals. The palaeoenvironment was a warm, shallow-water habitat. Based on greater proximity to the palaeo-coastline, the water depth was probably less than in other Upper Marine Molasse deposits.