Brontomerus mcintoshi is a newly discovered sauropod from the Early Cretaceous of North America. Brontomerus means "Thunder thighs" -- a name chosen because the peculiar shape of the hip bone shows that it would have had enormously powerful thigh muscles in life.
The quarry where the bones were found contains elements from at least two individuals, one of them three times as big as the other -- an adult and a juvenile. The life restoration shows a mother protecting her baby from a predator by using her powerful thigh muscles to deliver a devastating kick.
I'm sure that using the term "thunder thighs" will generate a few hundred extras hits for the blog from the non-palaeo crowd. Parents: don't let your kids google that term without adult supervision!