Humidity clung to the massive dinosaur as it swung its near-seven foot head towards a close-by female. He proudly displayed his crest, brandishing it about so she got an eyeful of his multiple horns, twisted and curled.

Seventy million years later, paleontologists from the Utah Museum of Natural History unearthed both Kosmoceratops richardsoni and Utahceratops gettyi in the Grand Staircase-Escalante National Monument of southern Utah. Like most ceratopsians, the famed dinosaurs that include Triceratops, these specimens possessed a splendid array of horns.

Kosmoceratops, the most-decorated dinosaur skull uncovered to-date, had fifteen horns—one above the nose and each eye with the rest curled forward over the frill curving around its neck. Utahceratops was similarly, though less elaborately, adorned.

Some theories suggest these fringes were for fighting. But Mark Loewan, one of the leaders of the study, says they were probably inefficient weapons due to their strange angles. Instead, Loewan thinks the horns were more for getting the girl.

“We tend to think they’re actually sexual signals used to intimidate rivals of the same sex, or attract mates of the opposite sex,” he says. “The real reason to have [horns] is so you look pretty for sexual selection.”

The idea of sexual selection dates back to Darwin and is illustrated in thousands of familiar species, including the antlers of deer or the plumage of peacocks. The more pronounced the decoration, be it exquisite or outlandish, the more likely that mate will be chosen to pass his genes (and endowments) onto the next generation.

In either of the recently announced species, the lady-killer would be the one with the most striking arrangement. According to Loewan, “The more different and bizarre, the better.”

This post first appeared on MIT Scope in October 2010