A discussion of the possible dinosaur-bird link based on new fossil evidence.
Below article from The San Francisco Chronicle reprinted for fair use purposes only -- copyright acknowledged.
This Megalania page has been visited times since April 10, 1998.
The San Francisco Chronicle
Copyright 1998 The Chronicle Publishing Co.
MARCH 19, 1998, THURSDAY, FINAL EDITION
SECTION: NEWS; Pg. A1
LENGTH: 581 words
New Evidence That Birds Evolved From Dinosaurs
BYLINE: David Perlman, Chronicle Science Editor
Fossil remains of two vastly different species of birds, discovered far apart in Mongolia and Madagascar, provide the most powerful evidence yet that modern birds are descended from the dinosaurs that once ruled the Earth.
Both the bird groups lived about 70 million years ago, and the unique features of each provide missing links that could settle the long and often acrimonious scientific controversy over the origin of the entire bird family, scientists say.
Two skulls of the Mongolian fossil birds were recently found in the Gobi Desert by a team from the American Museum of Natural History and the Mongolian Academy of Sciences. A report on that find was published yesterday in the journal Nature by Luis M. Chiappe of the American Museum of Natural History and his colleagues.
Although they were true birds, about the size of modern turkeys, the primitive creatures had stubby clawed ''forearms'' and thus were obviously unable to fly -- just as modern birds like penguins and the flightless cormorants of the Galapagos have lost their ability to fly.
The fossil creatures, named Shuvuui deserti for the Mongolian word meaning bird and the Latin word for desert, show many dinosaur characteristics, Chiappe said in an interview.
But the bony skulls possess several major features unique to birds, including one flexible section that enables birds to bend their snouts up and down in a motion called prokinesis so they can open their beaks wide to swallow large pieces of food. Dinosaur skulls show no such flexibility, Chiappe said.
''Shuvuui was a very weird- looking bird,'' Chiappe said, ''and although it lived some 80 million years after Archaeopteryx, the oldest known bird of all, it was still a very primitive creature.''
By contrast, the Madagascar fossil bird, about the size of a raven, could apparently fly. However, one sickle-shaped talon among its claws on each foot was so large and sharp that it closely resembled the deadly claws of Velociraptor, the fabled killer beast that starred in ''Jurassic Park'' and actually existed in the dinosaur age.
Such a claw, common in meat- eating dinosaurs that walked birdlike on their hind feet, is unknown even among today's most predatory birds.
The primitive Madagascar bird, the first of its kind known to science, provides another missing link in the controversy over the evolution from birds to dinosaurs, according to Catherine A. Forster, a paleontologist at the State University of New York.
It was Forster who uncovered the Madagascar bird's slashing talon in a block of sandstone filled with the partial skeleton of the creature. In a report appearing tomorrow in the journal Science, Forster and her colleagues said they have named the bird Rahona ostromi after the Malagasy word for a menacing cloud and the name of the late Yale paleontologist John Ostrom, who was one of the earliest and strongest proponents of the dinosaur-to-birds evolutionary theory.
Together with its lethal claws like Velociraptor's, the bird also had a long bony tail like many other dinosaurs, Forster said. Although Rahona, too, was extremely primitive, it also lived long after Archaeopteryx and closely resembled that early feathered flier, she said.
An article on the evolution of birds from dinosaurs in Thursday's editions of The Chronicle erroneously indicated that John H. Ostrom, a noted paleontologist, is deceased. He is a professor emeritus of geology at Yale University.
Back to Megalania Dinosaur News Page
Back to Megalania Dinosaur Page
Back to Megalania Home Page
Send Me Mail