沧龙 / Mosasaur

I’m a marine lizard with paddles—another branch turning the limb toolkit behind your body into swimming gear!
我是带桨状肢的海生蜥蜴——又一条支系，把你身体背后的四肢工具箱改成了游泳装备！

Sources
Three-dimensional dental microwear in type-Maastrichtian mosasaur teeth (Reptilia, Squamata)
https://www.nature.com/articles/s41598-023-42369-7
Regulation of body temperature by some Mesozoic marine reptiles.
https://doi.org/10.1126/science.1187443
Species reference
https://en.wikipedia.org/wiki/Mosasaur

Research context
Mosasaurs were marine lizards with paddle-like limbs. They illustrate another independent return to water, allowing comparison with ichthyosaurs, whales and the shared tetrapod limb plan.