An article from today's Telegraph:
THE fish ancestors of the first four-legged animals to
walk on land have been identified by scientists.
An analysis of a wide range of fossils has concluded
that at least three types of primitive fish began to
evolve and colonise land but only one turned its fins
into limbs and gave rise to the vast range of creatures
that now walk on the planet. The study, by Per Ahlberg,
of the Natural History Museum, and Zerina Johanson of
the Australian Museum, Sydney, ends a dispute over the
origin of land animals that has continued for more than
20 years.
At one time it was thought that our ancestors among fish
were the osteolepiforms - a group of extinct,
lobe-finned fish. But this idea fell out of favour and
palaeontologists began to suspect they were not our
direct ancestors but formed an evolutionary cul-de-sac.
The analysis, published in Nature, confirms that the
osteolepiforms were the ancestors of all four-limbed
land creatures, the tetrapods, which made the transition
from water to land about 370 million years ago.
Mr Ahlberg said: "We've traced the precise line of
evolution, or a very close approximation, from water to
land - through the lobe-finned fishes and up into the
earliest tetrapods."
/Gary