The Guanlong was one of the earliest tyrannosaurs ever discovered, and also one of the most stylish. Seriously, check out that chic head crest! Too thin and fragile to be a weapon, the crest was likely a built-in personal ad for attracting lonely lady Guanlongs. The discovery that such a strange ornament adorned the granddaddy of T-Rex revealed that there is much to be learned about tyrannosaur diversity. Artwork by HodariNundu.