Start Date
9-10-2023 3:45 PM
End Date
9-10-2023 5:00 PM
Access Type
Open Access
Abstract
The evolution and extinction of megatooth sharks, especially Otodus megalodon, have long puzzled scientists. A growing body of evidence suggests that the evolution of gigantism in these sharks, perhaps driven by their ability to thermoregulate, played a crucial role in their ecological success and response to environmental changes. Yet, until recently, the question of whether O. megalodon was ectothermic or endothermic was based solely on nonempirical inferences. In this presentation, Dr. Griffiths will present new research that involves the geochemical analysis of both modern and fossil shark teeth to shed light on O. megalodon's thermoregulation, revealing it maintained a warmer body temperature than its surroundings and supporting the idea that endothermy contributed to its gigantism. He will also show the potential to reconstruct the trophic level of these extinct sharks across the Cenozoic using various biogeochemical tracers of paleodiet, finding evidence that O. megalodon occupied an exceptionally high trophic level.
Biography
Michael completed his B.S. in Geosciences at the University of Wollongong in 2004, his M.S. in Geosciences at the University of Massachusetts in 2006, and Ph.D. in Physical Geography at the University of Newcastle (Australia) in 2010. He did his postdoctoral work at the University of California Irvine where he was a NOAA/UCAR Climate and Global Change Postdoctoral Fellow. Michael’s research is primarily centered around the use of biogeochemical tracers in sedimentary archives to explore changes in Earth’s biogeochemical cycles and by extension evolution of the earth’s natural systems.
Additional Links
ORCID
How Megatooth Sharks Ruled and Fell: Evidence from Stable Isotopes in Bioapatite
The evolution and extinction of megatooth sharks, especially Otodus megalodon, have long puzzled scientists. A growing body of evidence suggests that the evolution of gigantism in these sharks, perhaps driven by their ability to thermoregulate, played a crucial role in their ecological success and response to environmental changes. Yet, until recently, the question of whether O. megalodon was ectothermic or endothermic was based solely on nonempirical inferences. In this presentation, Dr. Griffiths will present new research that involves the geochemical analysis of both modern and fossil shark teeth to shed light on O. megalodon's thermoregulation, revealing it maintained a warmer body temperature than its surroundings and supporting the idea that endothermy contributed to its gigantism. He will also show the potential to reconstruct the trophic level of these extinct sharks across the Cenozoic using various biogeochemical tracers of paleodiet, finding evidence that O. megalodon occupied an exceptionally high trophic level.