Palaeontologists have found a dinosaur with a highly unusual array of features, including flippers, sickle-shaped “killer claws” and a swan-like neck. Halszkaraptor escuilliei, a relative of the infamous Velociraptor, is thought to have been a semi-aquatic predator that used its flipper-like forelimbs to manoeuvre in the water like a penguin. The discovery is the first …