With a name like paradoxus, you'd expect a little bit of weird from this tiny tyrannosaurid. First described in 2004, Dilong paradoxus took scientists by surprise with its downy coat. It was the first of its kind found to sport such proto-feathers, and it hinted that even the mighty Tyrannosaurus rex that followed some 50 million years later was not free of fuzz.

And Dilong isn’t done delighting researchers.

A recent study, published in Historical Biology, presents the first detailed analysis of Dilong's skull, which suggests the tiny tyrannosaurid's brain was S-shaped. This sinuous form differs from the linear brain of T. rex and is more commonly found higher up on the evolutionary tree.

“It's a paradox,” says lead