New Sickle-Clawed Fossil From Madagascar Links Birds and Dinosaurs
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A new raven-sized fossil bird, showing clear evidence of the close relationship between theropod dinosaurs and birds, has been discovered on the island of Madagascar by scientists working under a National Science Foundation (NSF) grant. This discovery was announced by a team of researchers -- led by paleontologist/anatomist Catherine Forster of the State University of New York (SUNY) at Stony Brook -- in this week's issue of the journal Science.
"This discovery is a wonderful example of how the fossil record provides the basic data for formulating, testing, and revising ideas about life through time," says Chris Maples, director of NSF's geology and paleontology program, which funded the research.
The fossil bird is 65 to 70 million years old and dates from the Late Cretaceous period. It was discovered in 1995 by an international team of paleontologists led by researcher David Krause, also of SUNY-Stony Brook. The scientists have named the new discovery Rahona ostromi, meaning "Ostrom's menace from the clouds." Scientists Scott Sampson (New York College of Osteopathic Medicine) and Luis Chiappe (American Museum of Natural History in New York) are also co-authors of the Science paper.
The forearm bone of Rahona is long and shows evidence of well-developed feathers, indicating it was a capable flyer. But unlike most birds, Rahona also had a long, bony tail and sported a large, sickle-like killing claw at the end of a thick second toe on the hind foot. This unique toe and claw is identical to the one carried by a group of fast, predaceous theropod dinosaurs called "maniraptorans." It is these maniraptoran dinosaurs (a group that includes Velociraptor and Deinonychus), that many, but not all, scientists believe gave rise to birds. "This new fossil is one of the strongest last nails in the coffin of those who doubt that dinosaurs had anything to do with the origin of birds," stated Forster.
Forster added, "Rahona was at the base of the bird family tree, right next to Archaeopteryx. It had a feathered wing and many bird features in its hips and legs, including a perching foot. But it also kept the big killing claw of its theropod ancestors." Paleontologists have long suspected that theropods gave rise to birds, and the presence of this "maniraptoran" toe and claw on the Malagasy bird "clinches it for us. This discovery lends a lot of weight to the idea that birds are a side-branch of the theropod family tree," says Forster.
The discovery was made during one of a series of ongoing paleontological expeditions in Madagascar, funded by NSF. In addition to Rahona, the scientific team discovered an array of well-preserved skeletal remains of other fossil animals, including theropod and sauropod dinosaurs, mammals, turtles, snakes, crocodiles and other birds. Another expedition to Madagascar is planned for this summer.
The National Science Foundation (NSF) is an independent federal agency that supports fundamental research and education across all fields of science and engineering. In fiscal year (FY) 2017, its budget is $7.5 billion. NSF funds reach all 50 states through grants to nearly 2,000 colleges, universities and other institutions. Each year, NSF receives more than 48,000 competitive proposals for funding and makes about 12,000 new funding awards.
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