Coronosaurus (“crowned lizard”) was a very close relative of Centrosaurus – so close, in fact, that it was originally named as a second species of Centrosaurus itself, before being recognized as a separate genus a few years later.
Living around 77 million years ago, it was a medium-sized centrosaur about 5m long (16′4″). Multiple specimens are known from two bone beds in Alberta, Canada, with different ages represented. Juvenile Coronosaurus skulls looked very similar to juvenile Centrosaurus, only developing their own distinct ornamentation as they matured.
It had a slightly backwards-pointing nose horn, brow horns that curved out to the sides, and a pair of downward-curving frill spikes. Uniquely among all known ceratopsians, it also had large irregular masses of short spikelets at the top of its frill forming a distinctive “crown”.