375 million-year-old fossil of ‘mother fish’ discovered

May 29th, 2008 - 5:36 pm ICT by admin  

Sydney, May 29 (IANS) A Museum Victoria team announced its latest and the most remarkable find Thursday — a 375 million-year-old fossil of placoderm fish with intact embryo and mineralised umbilical cord. The fossil, one of the most significant discoveries ever made by scientists, also happens to be that of the world’s oldest known vertebrate mother.

It provides the earliest evidence of vertebrate sexual reproduction, wherein the males (possessing clasping organs similar to modern sharks and rays) internally fertilised females.

This fossil has been named Materpiscis Attenboroughi, meaning “mother fish”, in honour of Sir David Attenborough, who first drew attention to the significance of the Gogo sites in his 1979 series Life on Earth.

Armour-plated shark-like fishes with no modern relatives, a second placoderm specimen containing three embryos was found earlier in 1986 and only recently recognised.

These embryos also provided the first data on their developmental biology, indicating the early sequence of bone formation in the placoderm’s growth stages.

An ultra-fine CT scanner at the Australian National University helped examine the old fossil in such an extraordinary state of preservation.

The team had also previously announced the first 3-D preserved muscle, nerve and circulatory tissues in a Devonian age (380 million years old) fish in 2007 paper in Biology Letters.

Earlier in 2005, Museum Victoria’s expedition to the Gogo fossil sites in north Western Australia, led by Dr John Long, made a swag of spectacular fossil discoveries, including that of a complete fish, Gogonasus, showing unexpected features similar to early land animals.

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