Sex Goes Way Back, Fossil Find Shows

The armored fish, Materpiscis attenboroughi, may have given birth to its young tail-first, similar to some sharks and rays. Credit: Museum Victoria.

From Live Science:

Remains of embryos entombed in their fish mothers' wombs for 380 million years have been found in fossils from an ancient rock outcrop in Western Australia. The finding is a big deal because it suggests that sex goes way back.

The prehistoric fish, called placoderms, are found at the base of the vertebrate evolutionary tree (in a large group we humans also belong to), so it now looks like sexual intercourse, and the mating behaviors that go along with it, were more widespread in these ancient animals than previously thought, said the scientists who made the discovery.

Read more ....