Australian sheep farmer finds oldest fossil

[Garrison Hilliard <garrison@efn.org>]

Sheep farmer finds oldest fossil
 
A sheep farmer in Australia has discovered a fossil of the world's oldest
vertebrate - the common ancestor of all animals with a backbone. 
Sheep station owner Ross Fargher found the fossil among a number of strange
shapes embedded in sandstone slabs on his farm - but after taking it home, he
left it on his veranda for four years before scientists identified its
importance. 

At 560 million years old, the fossil is around 30 million years older than the
next oldest vertebrate remains found so far, in China. 

"All that came before it presumably was something that was absolutely
microscopic, the size of an amoeba or a tiny organism, that wouldn't be
represented in the fossil record," palaeontologist Dr Jim Gehling, of the Museum
of South Australia in Adelaide, told BBC World Service's Science In Action
programme. 

"What it actually represents, I guess, is the deepest part of the tree of life."

Relations 

Dr Gehling explained that the fossil was around 6cm long, with a head shield and
a top dorsal crest. There was also a possibility it had once had a fin. 

He said that the creature "gave rise to everything that has some kind of
stiffening rod or backbone." 

The group is collectively known as chordates - vertebrates are only one type of
chordates, defined by the fact that their backbone is mineralised. 

"We'd call this a stem group chordate - one that is right at the bottom of the
line," he added. 

As a result it was a very important find in tracing the origin of our own
species, man. 

"Animals as we know them split off into many different branches very early on in
the piece - the problem is just how early," Dr Gehling stressed. 

"It's been assumed that they really only started to split off pretty much at the
beginning of the Cambrian [era, around 545 million years ago]." 

This theory had been contested over the last 20 to 30 years, however - and the
new discovery added weight to claims that man's origins were much older than
first believed. 

'A very good eye' 

Dr Gehling also outlined the extraordinary story of how the fossil had been
found in the first place. 

"The local sheep farmer - who is not a palaeontologist - had a very good eye and
he noticed he had some very curious shapes on some sandstone slabs," he said. 

These slabs had been looked at by friends, who in turn had contacted the Museum
of South Australia. The remarkable fossil was among these slabs. 

"It was discovered and lay there on his bungalow veranda for about five years
before anyone got to study it in any detail," Dr Gehling added. 

At first the scientists had believed the special fossil was a type of spriggina
- another type of creature from the early stages of evolution - but rubber casts
had revealed it was something quite different. 

Story from BBC NEWS:
http://news.bbc.co.uk/go/pr/fr/-/2/hi/science/nature/3208583.stm

Published: 2003/10/24 01:50:52 GMT

© BBC MMIII