• Earliest Known Ancestor of Placental Mammals Discovered April 2002 - National Geographic - Mammals that give birth to live young
  • Fossil sheds light on early mammals April 2002 - BBC
    A mouse-like fossil found in north-eastern China has been identified as the earliest known member of the family of mammals whose descendents include humans.

    'Fossil fish' in dramatic sighting

    The coelacanth is sometimes called "old four-legs"

    December 1, 2000 - BBC

    When Pieter Venter went on a recreational deep dive off South Africa's northeast coast in October, he did not expect to come across a living fossil.

    ``I looked at it carefully and after about six seconds I suddenly realized it was a coelacanth,'' Venter told reporters on Friday.

    A fish that had been swimming in the seas for some 400 million years, the coelacanth was believed to have been extinct for 70 million years until one was caught by a trawler off South Africa in 1938 and identified by a museum curator.

    Venter said he saw three coelacanths on his October dive, 104 meters (320 feet) below the surface. The discovery was made off Sodwana, a bay renowned for its reefs and diving.

    It was the first time a diver outside a submersible craft had seen the ancient species in its natural habitat. They have been observed from submersibles off the Comoro Islands, north of Madagascar.

    Venter took a team back to verify the discovery and to try to catch them on film.

    ``The first sighting was like seeing a UFO without taking a photograph,'' he said.

    On November 27, Venter's team found three coelacanths and filmed them at a depth of 115 meters (350 feet).

    The expedition was marred by tragedy as one of the team died after surfacing without proper decompression.

    The footage, which was shown to journalists, shows three fish ranging in length from one to two meters (three to six feet) ``standing'' on their heads and feeding off the ledge of an underwater canyon.

    The coelacanth -- known as ``old four legs'' because of its extra fins -- inhabits deep water caves and canyons, far from the prying eyes of most divers.

    Shallowest Find To Date

    The Sodawana fish are the shallowest find so far of the species and the only known population that can be reached by divers.

    ``This discovery suggests that the coelacanth may be far more widespread than was originally believed, perhaps anywhere where you get these deep canyons and old reefs in tropical waters,'' said marine biologist Johann Augustyn.

    The only other known population -- which may be a distinct sub-species -- is on the other side of the Indian Ocean, off Indonesia's remote Manado Tua Island.

    The Indonesian group only came to light in 1997 when an American marine biologist came across one in a fish market.

    Valli Moosa, South Africa's minister for environmental affairs and tourism, told reporters the exact location of the new discovery would be kept under wraps for now and authorities would regulate dives in the area to protect the fish.

    ``We want no human activity that will cause a disturbance for what is really a very vulnerable species,'' he said.

    The area of the discovery is already a protected marine reserve where fishing on the seabed is prohibited.

    Life's leap to land

    Life has flourished in the oceans for four billion years

    December 1, 2000 - BBC

    Life made the transition to land more than a billion years earlier than previously thought, according to new geological evidence.

    Organic material discovered within South African rocks suggests that microbes made the leap from the oceans to land about 2.6 billion years ago.

    Until now, 1.2 billion-year-old fossils of blue-green algae found in Arizona contained the earliest record of terrestrial life.

    The discovery gives scientists new information about the presence of life-sustaining oxygen in the Earth's atmosphere.

    An ozone shield and an oxygen rich atmosphere around the planet would have been needed for life on land to emerge.

    Organic matter

    The rocks come from what is now the Eastern Transvaal district of South Africa.

    They contain fossilised remnants of mats of photosynthetic bacteria, organisms that generate oxygen from water and atmospheric carbon dioxide.

    "This places the development of terrestrial biomass more than 1.4 billion years earlier than previously reported," said Yumiko Watanabe, of the Pennsylvania State University, US, in the scientific journal Nature.

    The researchers believe there may be even earlier fossil evidence of life on land, perhaps in Australia or Canada.

    The finding also has implications for the search for life on other planets.

    Collaborating scientists at the American space agency Nasa's Astrobiology Institute said they planned to search for signs of ozone around other planets in a future mission.