- Armored shark-like extinct fishes were probably the first animals to have had intimate sex by copulation.
- The world's first jaws likely evolved to facilitate mating, and not feeding, as had been previously thought.
- Genes responsible for making our limbs, and the pelvic fins of fishes, probably also played a role in developing the first sexual organs.
Fish were the first to have intimate sex, suggests new research based on well-preserved fossils of extinct armored fishes from the Gogo Formation of Western Australia.
Intimate sex by copulation likely first happened in the early Devonian Period around 400 to 410 million years ago, scientists say.
This was "not just spawning in water, but sex that was fun," according to project leader John Long, who also thinks that jaws evolved in conjunction with mating.
"Jaws might not have first evolved for feeding, as widely presupposed, but to facilitate copulatory mating," said Long, who is vice president of research and collections at the Natural History Museum of Los Angeles County. "In many sharks the jaws are used to hold on to pectoral fins of females so copulation can take place."