The two-meter skull of a newly discovered species of giant ichthyosaur, the earliest known, is shedding new light on the marine reptiles' rapid growth into behemoths of the Dinosaurian oceans, and helping us better understand the journey of modern cetaceans (whales and dolphins) to becoming the largest animals to ever inhabit the Earth.

While dinosaurs ruled the land, ichthyosaurs and other aquatic reptiles (that were emphatically not dinosaurs) ruled the waves, reaching similarly gargantuan sizes and species diversity. Evolving fins and hydrodynamic body-shapes seen in both fish and whales, ichthyosaurs swam the ancient oceans for nearly the entirety of the Age of Dinosaurs.

https://phys.org/news/2021-12-earth-first-known-giant-big-sperm.html