Otter-like critter swam lakes and rivers in the age of dinosaurs

Megacauda was an otter-like creature that inhabited lakes and rivers during the age of dinosaurs. Although it was dwarfed by most dinosaurs, this animal was twice as large as the next-largest member of the mammalian lineage in the Jurassic period. Furthermore, Megacauda displayed critical anatomical features that are shared with modern mammals, marking it as a significant discovery within the evolutionary history of mammals during the Jurassic era's aquatic environments.