Fossil fish fills evolutionary gap

[Waarnemer]

A 380 million-year-old fossil has filled a gap in understanding how fish evolved into the first land animals, Australian scientists say.
The perfectly preserved skeleton has revealed that fish developed features characteristic of land animals much earlier than once thought, said lead researcher John Long of Australia's Museum Victoria.
"We've got a fish from the Devonian period about 380 million years ago and preserved in three-dimensional stunning perfection," Long told

"It has revealed a whole suite of characters that link it to the higher land animals or tetrapods, so it's filling in a blank in evolution we didn't know about before."
The fossil of the Gogonasus fish, found in the remote Kimberley region of Western Australia at a site of a former major coral reef, shows the skull had large holes for breathing through the top of the head.
It also had muscular front fins with a well-formed humerus, ulna and radius -- the same bones found in the human arm, the researchers said.
"The degree to which these features resemble the earliest four-legged land animals makes Gogonasus a new model in the picture of how fishes evolved into land animals.
"Gogonasus is the missing clue in vertebrate evolution -- the world's first complete perfect skeleton of the kinds of fishes that gave rise to the first land animals."
The transition from a fish living in water to an air-breathing land animal with arms and legs was one of the most dramatic transitions in the history of evolution and many unsolved questions remained, Long said.
Earlier this year, scientists reported the discovery of Tiktaalik roseae, a 375 million-year-old species of fish seen as the missing link in the shift from water to land animals.
While Tiktaalik had a skull that was identical to an amphibian, Long said Gogonasus looks much more like a fish.
"I like to say it's a wolf in sheep's clothing. It's showing that evolution isn't as straightforward as we'd like to think."
The fossil was unveiled at the Melbourne Museum Thursday and will remain on display for a month.

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[Menydh]

380 million years is about the age of another fossil fish, the Coelacanthus. It was believed to have became extinguished about 60 million years ago (Cretaceic Period?), until one specimen was found off the coasts of South Africa in 1938. After the finding, there were attempts to find other speciments. To no avail. Then, scientists gave it as exitinguished once more. In 2001 another specimen was found in the fridge bilges of a fishing ship, off the coasts of Kenya. It was 177cm long.

I don't remember having heard that it had the semi-amphibious characteristics described for this Gogonasus (though it looks like it did in the picture below), but I do remember that it was suggested that the Coelacanthus was the missing link from water to land and all the way to the human.

Someone should give to the Spanish government the brilliant idea of giving fish human rights too, as they plan to do with apes.

Coelacanthus


A Coelacanthus fossil head


An artist interpretation of the Gogonasus


A fossil head of a Gogonasus



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