You can also handle an
Eoraptor skull, a Tyrannosaurus foot or even a Baryonyx claw.
They say the fossils, which were first unearthed in the 1930s in Tanzania, are those of a creature the size of a Labrador retriever, but with a five foot-long tail, that walked the Earth about 10 million years before more familiar dinosaurs like the small, swift-footed
Eoraptor and Herrerasaurus.
Another Argentinean creature, the smaller Eoraptor, has a similar identity crisis.
Paleontologists changed their minds about Eoraptor after they unearthed yet another close relative: Eodromaeus, a small, fleet theropod whose name means "dawn runner" (SN: 2/12/11, p.
In 1991 Dr Sereno found another species in the same valley called
Eoraptor. About the same size as Eodromaeus, it was a plant-eater whose descendants would include the giant long-necked sauropods such as Diplodocus.
Sereno's scientific expeditions started 22 years ago in the foothills of the Andes in Argentina, where he and his team of researchers uncovered what are believed to be among the first dinosaurs to roam the Earth, predators called Herrerasaurus and Eoraptor. Another scientist, Victorino Herrera, had found parts of Herrerasaurus first - and given it his name - in 1958, but Sereno's find included a skull and enough fragments to make a reconstruction of the 10-foot-long carnivore.
Sereno got the honor of naming Eoraptor, which means "dawn plunderer," a small, two-legged carnivore that looks a bit like a more graceful, miniature Tyrannosaurus rex, just 3 feet long and about 1 foot tall at the hip, with lightweight hollow bones.
The oldest and most basal theropods, such as
Eoraptor, Herrerasaurus, and the ceratosaurs (e.g., Coelophysis, Syntarsus, Dilophosaurus), have relatively short, raptorial fore-limbs (Welles 1984; Gauthier 1986; Colbert 1989; Sereno 1993; Sereno et al.
Eoraptor, or "dawn stealer," lacks nearly all the specialized features found in later dinosaurs.
Eodromaeus joins its kin
Eoraptor, a similar-sized dinosaur known to have lived in the same time and place.
'Dawn runner' Eodromaeus lived alongside
Eoraptor, a similar-sized, plant-eating dinosaur, whose descendants would eventually include the giant, long-necked sauropods.
Naming the creature
Eoraptor, Sereno unveiled the specimen earlier this month at a press conference and in the Jan.