A newly-discovered British fossil has been named Colymbosathon ecplecticos, Greek for "amazing swimmer with a large penis". This 5-millimeter-long ancestor of modern water fleas was buried in Herefordshire volcanic ash 425 million years ago that mineralized and preserved all of its soft body parts until the present. These remarkably preserved soft body parts include gills, eyes, swimming limbs - and a penis. This makes him the oldest fossil to bear that gender designation. Earlier fossils of other species show differences attributed to being male and female, but without clearly identifying who was what.
"The whole animal is amazing," noted David Siveter, first author of a paper announcing the find this week in the journal Science. "It is certainly the oldest penis in the world, that's for certain."
Also amazing is the proof that the so-called ostracode group of animals has changed little since the Silurian Period 430 million to 400 million years ago, while most other species underwent significant evolutionary redesign or disappeared altogether. "This specimen shows what nobody has been able to show before - 425 million years of unbelievable stability in an organism," Siveter said. "Most things that lived in the Silurian are long extinct and don't have many living relatives." Modern bivalve scavenger relatives to C. ecplecticos are found in virtually every aquatic environment on Earth, from deep oceans to shallow streams, from crabs and lobsters to more-distantly-related clams and oysters.
Researchers had to destroy the world's oldest penis in order to study it. They used a technique that combining thin-film cutting with computerized data storage. After removing the rock containing the fossil, repeated shavings 20 micrometers thick were cut through the remains. A photograph of each shaving was stored in a computer and later electronically reassembled and eventually combined in cyberspace to create a three-dimensional image of the animal along with its soft parts. The fossil itself, and the amazing organs it contained, is now dust.