25 February 2009

Sex started long before the Beatles

According to today’s Times sex has been around for at least 350 million years. The fossilised remains of a pregnant fish, Incisoscutum ritchiei, have provided the earliest known evidence of copulation and live births in the animal kingdom. Until the evolution of the armoured fish, sex is thought to have been limited to external fertilisation techniques in which sperm and eggs were squirted into the water to mix.

The species, 350-380 million years old, is the same age as another closely related fossilised fish, Materpiscis attenboroughi, which was found last year with a newly born offspring still attached by the umbilical cord.

Researchers said the discovery of two types of fish living at the same time shows copulation among vertebrates was a common means of reproduction some 200 million years earlier than had been thought. “Seen in one fossil, it could have been a one-off. With our new discovery we are beginning to think sex is characteristic,” said Dr Zerina Johanson, of the Natural History Museum in London. “We now have to rethink how animals reproduced way back then. We would have expected before this, that this very primitive fish had an external form of fertilisation. We are having to rethink that now. It’s challenging how we think about reproduction at this early evolutionary stage... Sex started a lot sooner than we thought.”

The embryo found inside I. ritchiei was originally thought to have been the mother fish’s last meal but was reassessed after the discovery of M. attenboroughi. Both species were found in Western Australia’s Gogo formation which is thought to be the remnants of a reef in tropical inland sea.

The two species of copulating animals were examples of placoderms which were a class of fish that had armoured plates on their heads and thorax and dominated the seas during the Devonian. They are the most primitive form of jawed vertebrates yet found and most were predators. Placoderm fossils have been found in Europe, North America, North Africa, Australasia and Antarctica.

Hmm it looks like Philip Larkin was a few million years out when he wrote in his poem Annus Mirabilis that:

Sexual intercourse began
In nineteen sixty-three
(which was rather late for me) -
Between the end of the Chatterley ban
And the Beatles' first LP.

Then again he was a poet and not a scientist,,,


Welshcakes Limoncello said...

Well, that just proves my Dad right: "Your generation didn't invent sex, you know."

Sean Jeating said...

Gosh, what would we do without scientists?
nineteen sixty three
would have been
a bit early for me.

Alwyn ap Huw said...

The scientists are wrong - what the armoured fish had was love not just sex!

TorAa said...

Sex started about 9 months before the first child ---

If naïve enough to believe that it just started without an evolution

Btw. Sorry for not visiting and commenting your excellent blog for a while. I can explain.

jams o donnell said...

I don't believe it for a moment Welshcakes. As far as I am concerned my parents only ever drank tea and read improving works. I was found under the gooseberry bush, left there by teh stork!

A rather early for my own sexual activity, a bit too late for my conception though Sean!

Haha Alwyn!

It's interesting to see finds ike this Tor.

SnoopyTheGoon said...

That's one capital post, Jams - both educational and exciting!

maryt/theteach said...

jams, and I suppose before 350 million years ago they just watched TV... :)

jams o donnell said...

Haha Snoopy glad you like it!

Absolutely not Mary. As we know the world was created at 9am on 23 October 4004BC

Roger B. said...

I always thought that sex started with The Big Bang!

jams o donnell said...

Haha Roger.. Just as well I was not involved or it would have been a small whimper!

Claudia said...

A bit late reading your fascinating post but it reminds me of those lines from Roland Young:

And here's the happy bounding flea
You cannot tell the he from she.
The sexes look alike you see;
But she can tell, and so can he.

Not to worry about when, where and how. They're certainly persistently around.....as us!

Devonshire Dumpling said...

As a child of the 60's (into flower power and all that) I can remember sex happening then. It's a vague distant memory but I think it was about even earlier than the 60's.

jams o donnell said...

Me I was a child in the 60s DD!