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Categories: Fossil fish Fossils Materpiscis Incisoscutum Placoderms Palaeontology

Sex more ancient and common than thought

Museum Victoria’s Head of Sciences, Dr John Long, has published research relating to a 375 million year old fossil fish which shows vertebrate sex, or internal fertilisation, and live birth are more ancient and more common in the prehistoric animal world than previously thought.

 

Click here to view larger image.
Austrophyllolepis
Image: Peter Trussler
Source: Museum Victoria

“Last year we discovered the world’s oldest mother, Materpiscis attenboroughi, a 375 million year old placoderm fish with embryo and umbilical cord attached, so we knew that internal fertilisation, or sex, was happening. We just didn’t know how. With this discovery we now know how they were doing it,” said Dr John Long, Head, Sciences, Museum Victoria.
 
The discovery of Materpiscis last year made international headlines and was so significant that it was named after the renowned naturalist Sir David Attenborough.

This latest finding, by Dr Long along with Dr Kate Trinajstic from the University of Western Australia and Dr Zerina Johanson from London’s Natural History Museum, is one of the most significant palaeontological finds ever made and is published today in the prestigious journal Nature.


Click here to view larger image.
380-million-year-old placoderm fish, Incisoscutum, from Gogo, Western Australia showing an embryo inside it. This gave clues that these fishes must have been reproducing using internal fertilisation.
Image: Natural History Museum, London
Source: P50934 from the Natural History Museum, London

“It was the discovery of Materpiscis which enabled the finding of the new embryos inside Incisoscutum, originally thought to be its last meal,” explained Dr Long.

Dr Long said the new find also showed that more than one type of ancient fish (Incisoscutum and Austrophyllolepis) had structures leading to pelvic claspers, as current-day male sharks do. The discovery of these structures proves the existence of internal fertilisation, or sex involving copulation, which shifts the evolutionary origin of this reproductive mode further back in time.

 

 

Both species belong to the Placoderms, an extinct group of jawed fish that were the dominant group of vertebrates throughout the Middle Palaeozoic Era (c. 420 to 350 million years ago) and 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 recognised as one of the world’s leading palaeontologists and has published over 200 scientific papers and general science articles, and 25 books. His research focuses on the early evolution of vertebrates (fishes) as well as dinosaurs, megafauna and general evolutionary theory. He has collected fossils in Antarctica, Africa, throughout Asia, and has worked extensively in North America, Europe and Australia. Dr Long has named 50 new species of prehistoric creatures, including a new dinosaur, as a result of his research and discoveries.

Incisoscutum and Austrophyllolepis will both go on display in the foyer of Melbourne Museum from February 26.

Melbourne Museum
Nicholson Street, Carlton
Ph 13 11 02 or visit museumvictoria.com.au

Image Galery:

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Contact: Rod Macneil, Public Relations Manager, Museum Victoria, Ph: +61 3 8341 7753 rmacneil@museum.vic.gov.au

Source: Museum Victoria

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