Stegosaurus plates provide first solid evidence that male, female dinosaurs looked different

Stegosaurus plates provide first solid evidence that male, female dinosaurs looked different. Posted April 27, 2015; 09:30 a.m. by Morgan Kelly, Office of The discovery of a single anatomical difference between males and females of a species of Stegosaurus provides some of the most conclusive evidence that some dinosaurs looked different based on sex, according to new research. Princeton University research published in the journal PLoS ONE found that the back plates of the species Stegosaurus mjosi came in two varieties that indicated the animal's sex — short and wide, and tall and narrow. Females had one type of plate and males donned the other. The lack of a particular female-specific bone tissue found in birds and some dinosaurs, however, made it difficult to determine which sex had which plate type. Author Evan Saitta, who graduated from Princeton in 2014 and conducted the research for his senior thesis project , nonetheless drew from existing animals, particularly horned animals, to suggest that the distinct shape of male and female  S. mjosi  plates indicated two different functions. He supposes that the tall, narrow plates belonged to females, who would have needed the pointier plates to defend themselves against predators.