A SLOUCHING reptile that lived before the dinosaurs is being hailed as the first species in which males used sexual ornaments to compete for females.
Diictodons were metre-long plant eaters that lived 250 to 260 million years ago. Fossil hunters have often found diictodon skulls with 3-centimetre tusks alongside tuskless skulls, but didn鈥檛 know why. Now Robert Reisz of the University of Toronto and his team have found the two types were equally common, which fits the idea that only the males had tusks. They report in a future issue of Proceedings of the Royal Society B that there were no signs of wear on the ends of the tusks, meaning the animals did not dig or chew with them.
The tusks, says Reisz, signalled 鈥淚鈥檓 bigger than you, so back off.鈥�
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