Drivers of Mosasaur Evolution

 Phylogeny vs Time

 Oceanic Upwelling Locales

 Mosasaur Fossil Locales

Physical Drivers of Mosasaur Evolution

Authors:

1. Michael J. Polcyn (a)
2. Louis L. Jacobs (a)
3. Ricardo Araújo (a, b)
4. Anne S. Schulp (c, d)
5. Octávio Mateus (b, e)

Affiliations:

a. Roy M. Huffington Department of Earth Sciences, Southern Methodist University, Dallas, Texas 75275, USA

b. Museu da Lourinhã Rua João Luis de Moura, 95. 2530–158 Lourinhã, Portugal

c. Natuurhistorisch Museum Maastricht, de Bosquetplein 6–7, NL-6211 KJ Maastricht, The Netherlands

d. Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, The Netherlands

e. Departamento de Ciências da Terra, FCT, Universidade Nova de Lisboa, Lisbon, Portugal

Abstract:

Mosasaurs are marine squamates with a 32.5 million-year history from their appearance at 98 Ma to their extinction at the K-Pg boundary (65.5 Ma). Using a database of 43 generic and 94 species-level taxa, we compare the taxonomic diversity and patterns of morphological disparity in mosasaurs with sea level, sea surface temperature, and stable carbon isotope curves for the Upper Cretaceous to explore factors that may have influenced their evolution. No single factor unambiguously accounts for all radiations, diversification, and extinctions; however, the broader patterns of taxonomic diversification and morphological disparity point to niche differentiation in a “fishing up” scenario under the influence of “bottom-up” selective pressures. The most likely driving force in mosasaur evolution was high productivity in the Late Cretaceous, driven by tectonically controlled sea levels and climatically controlled ocean stratification and nutrient delivery. When productivity collapsed at the end of the Cretaceous, coincident with bolide impact, mosasaurs became extinct.