New Sickle-Clawed Fossil From Madagascar Links Birds And Dinosaurs

NOTE: Original embargo of 4 p.m. EST, March 20, 1998 was lifted at 2 p.m. EST, March 17, 1998 by Science

A new raven-sized fossil bird, showing clear evidence of theclose relationship between theropod dinosaurs and birds, has beendiscovered on the island of Madagascar by scientists workingunder a National Science Foundation (NSF) grant. This discoverywas announced by a team of researchers -- led bypaleontologist/anatomist Catherine Forster of the StateUniversity of New York (SUNY) at Stony Brook -- in this week'sissue of the journal Science.

"This discovery is a wonderful example of how the fossilrecord provides the basic data for formulating, testing, andrevising ideas about life through time," says Chris Maples,director of NSF's geology and paleontology program, which fundedthe research.

The fossil bird is 65 to 70 million years old and dates fromthe Late Cretaceous period. It was discovered in 1995 by aninternational team of paleontologists led by researcher DavidKrause, also of SUNY-Stony Brook. The scientists have named thenew discovery Rahona ostromi, meaning "Ostrom's menace from theclouds." Scientists Scott Sampson (New York College ofOsteopathic Medicine) and Luis Chiappe (American Museum ofNatural History in New York) are also co-authors of the Sciencepaper.

The forearm bone of Rahona is long and shows evidence ofwell-developed feathers, indicating it was a capable flyer. Butunlike most birds, Rahona also had a long, bony tail and sporteda large, sickle-like killing claw at the end of a thick secondtoe on the hind foot. This unique toe and claw is identical tothe one carried by a group of fast, predaceous theropod dinosaurscalled "maniraptorans." It is these maniraptoran dinosaurs (agroup that includes Velociraptor and Deinonychus), that many, butnot all, scientists believe gave rise to birds. "This new fossilis one of the strongest last nails in the coffin of those whodoubt that dinosaurs had anything to do with the origin ofbirds," stated Forster.

Forster added, "Rahona was at the base of the bird familytree, right next to Archaeopteryx. It had a feathered wing andmany bird features in its hips and legs, including a perchingfoot. But it also kept the big killing claw of its theropodancestors." Paleontologists have long suspected that theropodsgave rise to birds, and the presence of this "maniraptoran" toeand claw on the Malagasy bird "clinches it for us. Thisdiscovery lends a lot of weight to the idea that birds are a sidebranch of the theropod family tree," says Forster.

The discovery was made during one of a series of ongoingpaleontological expeditions in Madagascar, funded by NSF. Inaddition to Rahona, the scientific team discovered an array ofwell-preserved skeletal remains of other fossil animals,including theropod and sauropod dinosaurs, mammals, turtles,snakes, crocodiles and other birds. Another expedition toMadagascar is planned for this summer.