Manuel Amadori wird für seine Dissertation Palaeobiology and Taxonomy of the extinct elasmobranch shark, †Ptychodus (Vertebrata, Chondrichthyes) ausgezeichnet.
The extinct shark Ptychodus is an enigmatic predator, who dominated worldwide marine environments during most of the Late Cretaceous (ca. 100-85 Mya). Pavement-like dentitions composed of massive teeth suggest that Ptychodus mainly fed on hard-shelled prey (durophagy). This shark is characterized by elongated jaws and crushing teeth, which are typical for today’s small durophagous meso-predators (e.g., horn sharks), combined with a body size, which exceeds that of modern marine top predators (e.g., white sharks). Although Ptychodus is well known from many sites around the world, its temporal and spatial distribution and the reasons for its extinction are still unclear and strongly debated. A variety of fossil remains, such as well-preserved tooth plates and cartilaginous jaw elements from various continents form the core material of the present study. Both traditional and new, modern analytical approaches were employed successfully here to support species identifications and to investigate tooth arrangement and wear patterns in Ptychodus. The reconstruction of temporal and spatial range for the species of Ptychodus confirm an almost ubiquitous distribution for this voracious predator. The results also indicate that Ptychodus was very successful in terms of species diversity in both near- and offshore environments. Interestingly, these sharks vanished significantly before the mass extinction that wiped out the dinosaurs at the end of the Cretaceous. Although multiple biotic and abiotic factors most likely were major drivers during the evolutionary history of Ptychodus, the lack of preferred prey (e.g., armoured ammonites), might have been the major trigger for its decline. The present study lays the foundations for clarifying the effects of environmental changes on highly specialized sharks over long temporal scales and identifying possible extrinsic stressors underlying evolutionary changes. Consequently, my results help in establishing evolutionary models for specialized sharks in general and for understanding the importance of durophagous adaptations within the complex evolutionary history of sharks, but also for maintenance of functioning marine food webs.
Manuel Amadori is an Italian paleobiologist mainly interested in the study of shark evolution. He obtained his Bachelor's degree in Biological Sciences at the University of Urbino, Italy (2015) and his Master’s degree in Biodiversity and Evolution at the University of Bologna, Italy (2018). Since then, his research activity focuses on fossil sharks. He successfully concluded his PhD in Natural Science at the University of Vienna (2022). Various grants received before and during his PhD studies financed most of his past scientific research. Currently, he is member (Postdoctoral Researcher) of the Evolutionary Morphology Research Group (University of Vienna) and works on a project on Jurassic sharks (ca. 200-145 Mya) from Europe, which is supported by the Austrian Science Fund (FWF).