Fossils

While dwarfed by most dinosaurs, Megacauda was twice as big as the next-largest member of the mammalian lineage in the Jurassic and displayed critical anatomical features shared with modern mammals.

Researchers described the new species — named Perucetus colossus, or "the colossal whale from Peru" — in the journal Nature on Wednesday.

An unusual find in China suggests some early mammals may have hunted dinosaur for dinner — adding to growing evidence that even when dinosaurs ruled the Earth, some mammals were biting back.