26 February 2009
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| Monash Alumnus, artist Peter Trusler has recreated the likeness of the Placoderms, an extinct group of fish from the Middle Palaeozic Era. Their fossilised remains, studied by honorary researcher Dr John Long and a team of palaeontologists, have revealed significant findings about evolution. |
New research by Monash University honorary researcher, Dr John Long reveals that vertebrates have been having sex for more than 375 million years -- making sexual intercourse more ancient than scientists first thought.
The evidence of the first vertebrate sex has been confirmed in a fossilised fish, which was named last year after the British naturalist David Attenborough.
Dr Long said the latest revelation proves that the sexual activity of the first vertebrates involved copulation, which shifts the evolutionary origin of this mode of reproduction further back in time.
"Further investigation of the fossilised remains of the placoderm, or armoured jawed fished, have revealed they had pelvic fins with structures similar to claspers, as in modern sharks, which confirms the way they had sex involved internal fertilization," Dr Long said.
This collaborative research by Dr Long, together with Dr Kate Trinajstic from the University of Western Australia and Dr Zerina Johanson from London's Natural History Museum, is a very significant palaeontological discovery and is published today in the prestigious journal Nature.
The findings were made using the same fossil which last year made world-wide headlines and became known as world's oldest mother, Materpiscis attenboroughi, a placoderm fish with embryo and umbilical cord attached.
"The discovery of Materpiscis attenboroughi confirmed animals were reproducing 375 million years ago, but we didn't know how this was happening. Our study of the fossil shows that reproduction was achieved through intercourse," Dr Long said.
The Placoderms are an extinct group of jawed fish that were the dominant group of vertebrates through the Middle Palaeozic Era (c. 420 to 350 million years ago), which had bony plates of armour on their heads and bodies. The placoderms, often referred to as the ‘dinosaurs of the seas', were the rulers of the world's lakes and seas for almost 70 million years.
Dr Long is renowned as one of the world's leading paleontologists and has published more than 250 scientific papers, articles and books. He is Head of Sciences at Museum Victoria and his research is focused on the early evolution of vertebrates, dinosaurs and megafauna and has discovered 50 new species due to his extensive research with fossils throughout the world.
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