August 29 2006 at 11:32AM
Sydney - An Australian fossil find may mean living creatures left the world's oceans for the land much earlier than once thought, rewriting a small part of mankind's evolution, scientists said on Tuesday.
A study of rocks collected near Buchan in Victoria state's East Gippsland has yielded a lung fish fossil more than 20 million years older than earlier finds, Macquarie University researcher Zarena Johanson told AFP.
Her Macquarie colleague, Professor John Talent who found the rocks, said the fossilised lung fish - or coelacanth - sets back the timeline for when marine animals made their first excursions on to land.
"It seems from experimental data with living coelacanths that there should have been older ones," Talent said.
"What we've done is close the gap - we've got the fossil right back near the origin of this group."
The discovery is described in the latest issue of the international journal Biology Letters.
The coelacanth, which the paleontologists describe as a "living fossil" fish with "proto legs", was once thought to have become extinct with the dinosaurs 65 million years ago.
However, it was rediscovered living in the Indian Ocean in 1938.
This new fossil, a single lower jawbone, is nearly 410 million years old, much older than previously known coelacanth fossils, Johanson said.
The new species, Eoactinistia foreyi, fills a gap in fossil records of the fish, which were previously known to reach back 390 million years.
Johanson said there is at least 30 years worth of work remaining on the rocks from the East Gippsland find, but wants more.
"A lot of our finds in Australian come from farms with exposed rocks. So we encourage farmers to keep an eye out," she said.
The fossil is the latest in a list of ancient creatures including sabre-toothed kangaroos, horned "devil wallabies" and the unlikely-sounding "demon duck of doom" that are reshaping views of Australia's prehistoric past.
Scientists had long wondered whether the appearance of humans in Australia 45 000 years ago led to the extinction of the continent's mega-fauna.
However, this month a team from the University of Melbourne and La Trobe University released a study arguing that climate change killed the giant beasts up to 10 000 years before man arrived. - Sapa-AFP