What got female duck-billed dinosaurs in the mood to make baby dinos? Perhaps it was something never before seen in the fossil record: a sexually suggestive fleshy comb, like that of roosters, on the head and neck of males. A mummified specimen of the duckbill Edmontosaurus regalis, discovered by an international team in the west-central region of Canada’s Alberta province, proudly preserves just such a structure (shown above in artist’s reconstruction). The team, which reports the find online today in Current Biology, points out that some duckbills had bony crests on their heads, which are easily preserved in fossil form, and that researchers had suggested functions for such crests ranging from sexual display to external olfactory organs. But E. regalis, a so-called flat-headed duckbill, does not have a hard, bony crest, making this first discovery of a soft tissue version all the more important for understanding dino behavior. Because birds evolved from dinosaurs, and the combs of roosters and other birds are widely considered to be for sexual display, the team concludes that this is also the most likely explanation for its presence in some duckbills.

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