Australia: fossil fish Gogonasus ancestor to land animals


This video says about itself:

There are few dinosaur remains in Western Australia because the majority of our rocks are far older than the dinosaurs.

From ABC in Australia:

Ancient fish was advanced for its age

By Anna Salleh for ABC Science Online

Fish developed features characteristic of land animals much earlier than once thought, researchers say.

Dr John Long of Museum Victoria and his colleagues base their conclusions on an uncrushed 380 million-year-old fish fossil found in Western Australia.

“The specimen is the most perfect complete three-dimensional fish of its kind ever discovered in the whole world,” says Dr Long, who reports the team’s findings online today in the journal Nature.

“It looks like it died yesterday. You can still open and close the mouth.”

Dr Long says the preserved remains of a Gogonasus fish from the Devonian period were found last year in the remote Kimberley area at the Gogo fossil site, once an ‘ancient barrier reef’ teeming with fish.

He says previous analyses based on limited material suggested Gogonasus had relatively primitive features.

But when his team used a CT scanner at the Australian National University to analyse this new fossil, it found the fish had a number of features common to land animals.

“It’s hiding a lot of deceptively advanced features that were not recognised before until we had such a perfect specimen,” Dr Long said.

For example, Dr Long says Gogonasus had hole in its skull similar to that found in the first land animals.

He says this hole eventually became the eustachian tube in higher vertebrates.

Dr Long’s team’s analysis also revealed the fish’s pectoral fin had the same pattern of bones as the forelimbs or arms of land animals, called tetrapods.

“It’s definitely a fish. It’s got gills, it swims in water, it’s got fins,” Dr Long said.

“But it’s a fish that is showing the beginnings of the tetrapod’s advanced body plan that would eventually carry on to all living land animals.”

Dr Long says Gogonasus also had a cheek bone structure similar to early amphibian and a single pair of nostrils, like humans.

Wolf in sheep’s clothing

Earlier this year scientists reported the discovery of Tiktaalik roseae, a 375 million-year-old species of fish that filled the evolutionary gap in the transition between water and land animals.

While Tiktaalik had a skull that was identical to an amphibian, Dr Long says Gogonasus looks much more like a fish.

“This particular fish is a bit like a wolf in sheep’s clothing,” he said.

In fact, Dr Long says Gogonasus is more closely related to land animals than a fish called Eusthenopteron, which until recently was considered the common ancestor of all land animals.

“It’s replaced Eusthenopteron as the best fish to use when studying the ancestry of the first tetrapods,” Dr Long said.

Dr Long says there are still many unsolved questions about the evolution of land animals, such as how fin rays evolved into digits.

And he says such questions will only be solved with the discovery of more fossils in combination with embryology and other evolutionary development work.

Dr Long named Gogonasus, meaning ‘snout from Gogo’, in 1985 when he discovered a snout of the same species, also at the Gogo fossil site.

See also here.

And here.

A massive plunge in global oxygen levels – and not freshwater frolicking – could have led to the rise of air-breathing animals on Earth, a new study argues. Australian researchers have made the claim after analysing the fossilised remains of a new lungfish species from Gogo in northern Western Australia that lived roughly 375 million years ago: here.

3 thoughts on “Australia: fossil fish Gogonasus ancestor to land animals

  1. World’s oldest embryo found in fossilised fish

    * 28 May 2008
    * Emma Young
    * Magazine issue 2658

    The world’s oldest embryo – and the first fossilised umbilical cord – have been discovered inside a 380-million-year-old fish fossil in Australia. The find pushes back proof of internal fertilisation and live birth by about 200 million years.

    “When I saw the embryo I went weak at the knees,” says John Long of the Museum Victoria in Melbourne, who led the work. “I just couldn’t believe it.”

    The specimen is a new species, which the team has named Materpiscis attenboroughi, in honour of David Attenborough (Nature, vol 453, p 650). It was Attenborough who first drew public attention to the Gogo formation in Western Australia, where their fossil was found, in the BBC’s 1979 series Life on Earth.

    M. attenboroughi belongs to an extinct group of armoured shark-like fish called placoderms. The most primitive vertebrates with jaws, they are the ancestors of modern sharks and bony fish.

    http://www.newscientist.com/channel/life/mg19826583.600-worlds-oldest-embryo-found-in-fossilised-fish.html?feedId=life_rss20

    Like

  2. Pingback: World’s oldest embryo discovered in 380 million year old fish | Dear Kitty. Some blog

  3. Pingback: Fungus, oldest land fossil, discovered | Dear Kitty. Some blog

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.