9:39pm UK, Friday September 13, 2002

Scientists have stumbled upon the oldest known penis - a 100m-year-old specimen belonging to a microscopic creature.

SP ostracod crustacean with big dick

The 100-million-year-old ostracod, primed for action. Apparently

The tiny crustacean was caught in flagrante, and fossilised as he prepared for his big moment.

"To my knowledge it is the oldest penis. I don't know of any older," Professor David Siveter, of the University of Leicester, told the British Association science conference.

"It was preparing for a sex act, though we do not have the fossil of the female - unless it was a 100m-year-old flasher."

Equipment

Scientists knew it was a male, because it had a penis. In fact, it had two.

"It doesn't have one penis, it has two joined together called a hemipene, that were a third of the length of its body," said Prof Siveter.

There's a reason why the ostracod was so well endowed. It had the longest sperm in the animal kingdom and needed serious equipment to deliver its goods.

At only 1mm in length, the ostracod may not be the largest romeo in the animal world.

Prolific

But the sperm it produces is among the largest made by any creature - about10 times its body length.

The fossil was discovered in rock from the Cretaceous era, 146m to 65m years ago, when dinosaurs ruled the Earth.

No trace of its mate - if it had one - has been found.