Did Horny Young Dinosaurs Cause Illusion of Separate Species?

摘要

Of all the strange-headed dinosaurs, the prize for toughest, prickliest noggins probably belongs to the pachycephalosaurs-literally, the "thick-headed lizards." Some sported domed skulls, and all had bony spikes studding their long snouts. Four species are known from roughly 65-million-year-old rocks in Wyoming, Montana, and South Dakota alone. It's an impressive display of diversity for the waning days of the dinosaurs.