Colossus of the sea: gigantism in Mosasauroidea (Reptilia: Squamata)

• Applicant: Paulina Jimenez-Huidobro, Ph.D.
• Subject Area: Palaeontology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 464349130

Mosasauroidea represents one of the most highly adapted groups in the history of Squamata. They evolved paddle like limbs and radiated into the aquatic environments during the Late Cretaceous. During the radiation of the group, two lineages, Mosasaurinae and Tylosaurinae, reached convergently gigantic body sizes. This present project aims to study the evolution of mosasauroids from three different perspectives: (1) phylogenetic relationships that represent the evolution from small-to-medium sized facultatively aquatic lizards to big-to-gigantic sizes fully aquatic forms; (2) the physiological adaptations and growth conditions under which fully aquatic mosasauroids reached gigantic body sizes; (3) as well as the cerebral and sensorial adaptations involved in their evolution. The present project is a continuation of the current DFG project, from which new research questions arise regarding life history traits studies and craniofacial soft tissue analyses, as proxy of aquatic adaptations and endothermy. Based on the current evidence, I propose that derived mosasauroids would have evolved endothermy, a thermoregulation strategy reached via high metabolic rate and fast growth. I also hypothesize that the development of high craniofacial vascularization and sensory traits would correlate with the ecological position of mosasauroids as apex predators, that would, in turn, be consistent with their phylogenetic affinities. The results would contribute to the understanding of the paleobiology, physiology, ecology, and evolution of Mosasauroidea, Mosasauria, and ultimately, the evolution of Squamata.

• DFG Programme: Research Grants
• International Connection: Argentina, Canada, USA
• Co-Investigators: Professor Dr. Thomas Martin; Rachel Racicot, Ph.D.; Privatdozentin Dr. Irina Ruf
• Cooperation Partners: Dr. Michael Caldwell; Dr. Takuya Konishi; Dr. Ariana Paulina-Carabajal