And, apparently, so did prehistoric fish:
BANGKOK, Thailand (AP) — The fossilized remains of two pregnant fish indicate that sex as we know it – fertilization of eggs inside a female – took place as much as 30 million years earlier than previously thought, researchers said Thursday.
Scientists from Australia and Britain studying 380 million-year-old fossils of the armored placoderm fish, or Incisoscutum richiei, said they were initially confused when they realized that the two fish were carrying embryos. They originally thought the fish laid their eggs before fertilization.
“Once we found embryos in this group, we knew they had internal fertilization. But how the hell are they doing it?” said John Long, the head of sciences at the Museum Victoria in Melbourne who wrote a paper on the discovery that appeared in Thursday’s issue of the journal Nature.
The answer came when the scientists re-examined the pelvis of the male placoderm, armed with the new information about fertilization. After looking at specimens at the Natural History Museum in London and the Museum Victoria, they realized the pelvis had a fin not seen on the female fish, and surmised it was likely used to grip its mate during fertilization, much as sharks do.
“These fish have an extra large bone that attaches to the pelvic bone,” he said. “It had been overlooked and hadn’t been identified. So in a nutshell, we have reinterpreted the structure of the pelvic bone in these placoderms to show they had a method for copulation.”
Well, I guess you had to find something to do 30 million years ago.
