Through other physical features, they also show a connection between jawless fish
and placoderms, which were previously considered unrelated.
"Essentially what we found is that the genetic roots of the vertebrate jaw can be found in the embryos of a weird jawless fish
called the sea lamprey," said Daniel Meulemans Medeiros, lead author of the study.
Another aim is to protect river lampreys, a primitive kind of jawless fish
. An English Nature spokesman said: "Protecting and managing fisheries on the River Tweed has not only been good for the fish.
Cute it's not, but the lamprey - a jawless fish
of ancient origin - deserves protection under the federal Endangered Species Act, said a dozen West Coast conservation groups in a lawsuit they filed Wednesday.
Writing about their study in the journal PLoS Biology, the researchers said that the first vertebrates to have teeth were a group of eel-like jawless fish
, known as the conodonts, which had teeth not in their mouth, but lining the throat.
Instead, these early jawless fish
appear to have had skulls and other skeletal structures made of cartilage, says Simon Conway Morris of the University of Cambridge in England, who collaborated with the Chinese team.
Washington, July 21 (ANI): In a new research, scientists have discovered that the sea lamprey, which emerged from jawless fish
first appearing 500 million years ago, dramatically remodels its genome.
Scientists in 1976 identified the fossils, called Anatolepis, as the scales of a jawless fish
. Subsequent workers have debated whether these plates belong to a fish or an arthropod-the phylum of segmented invertebrates that includes insects and crustaceans.
The oldest known vertebrates, a collection of remarkably well-preserved remains of 30 jawless fish
, have been discovered by an international team of paleontologists in the mountains of southern Bolivia, according to an announcement last week by the National Geographic Society in Washington, D.C., which funded the expedition.
Fossils of primitive, jawless fish
dating back 470 million yearsare the oldest known examples of vertebrates, a subphylum to which both human beings and salamanders belong.