After sideways start, sex lost its appeal for eons

摘要

If you're going through a dry patch, it's nothing compared to the entire animal kingdom, which appears to have gone tens of millions of years without copulating after the first jawed fish, Microbrachius dicki, started doing it 380 million years ago. 'The very first act of copulation was done sideways, square-dance style," says John Long from Flinders University in Adelaide, Australia. Long and his colleagues carried out a new analysis of the fossil fish M. dicki. They have evidence that the fish - from a group known as gnathostomes -reproduced via internal fertilisation. This suggests that all gnathostomes were doing it too. On the male specimens of M. dicki the team found bony structures that spread out on each side of the fish. with a groove that would have delivered the sperm. On the females, there were spiny plates that would have acted like Velcro, holding the male in place (Nature, doi.org/wf7).