Sea level regulated tetrapod diversity dynamics through the Jurassic/Cretaceous interval

Area of Science:

• Paleobiology
• Macroevolutionary dynamics
• Fossil record analysis

Background:

• Reconstructing deep time biodiversity trends is crucial but challenging due to uneven fossil sampling.
• The Jurassic/Cretaceous (J/K) boundary (145 million years ago) is poorly understood regarding extinction and radiation events.

Purpose of the Study:

• To assess macroevolutionary dynamics of tetrapods across the J/K boundary.
• To clarify extinction and radiation patterns despite sampling biases in the fossil record.

Main Methods:

• A rigorous subsampling approach was applied to a comprehensive tetrapod fossil occurrence dataset.
• Analysis focused on macroevolutionary dynamics through the J/K transition.

Main Results:

• Nearly all higher tetrapod groups experienced a significant decline across the J/K boundary.
• Several important tetrapod clades went extinct, while numerous modern groups radiated and experienced ecological release.
• Patterns were primarily driven by variations in eustatic sea level.

Conclusions:

• Eustatic sea level changes significantly impacted tetrapod biodiversity by altering shallow marine environments and promoting allopatric speciation.
• The J/K boundary was a critical period for tetrapod macroevolutionary change, leading to the diversification of modern groups.