It now appears that those creatures shared the southern part of the supercontinent Pangaea - now South America, Africa, Antarctica and Australia - with N parringtoni. "If the newly named Nyasasaurus parringtoni is not the earliest dinosaur, then it is the closest relative found so far," said lead researcher Sterling Nesbitt, a postdoctoral biology researcher at the University of Washington. The findings, detailed online Dec. 5 in the journal Biology Letters, push the dinosaur lineage back 10 million to 15 million years than previously known, all the way into the Middle Triassic, which lasted from about 245 million to 228 million years ago. [See Photos of the Oldest Dinosaur Fossils] 
 
 Dating a dinosaur 
 
 The study is based on seemingly few bones — a humerus or upper arm bone and six vertebrae — though Nesbitt pointed out much of what we know about dinosaurs comes from similar number of fossils. The researchers, from the University of Washington and University of California Berkeley in the US and the Natural History Museum, re-examined a number of bones that were first collected from what is now Lake Malawi in southern Africa. "It's kind of your shoulder muscle or the equivalent in a dinosaur," Nesbitt told LiveScience, adding that "early dinosaurs are the only group to have this feature." "I first saw the bones in the 1970s when the late Alan Charig (one of the co-authors) showed them to me," Sues, of the National Museum of Natural History in Washington, D.C., told LiveScience in an email.
– Scientists studying fossilized bones originally discovered in Tanzania in the 1930s may have revealed Earth's oldest known dinosaur, LiveScience reports. Nyasasaurus parringtoni lived between 240 million and 245 million years ago, some 10 million to 15 million years earlier than any other dinosaurs previously discovered. Researchers stopped short of calling the Nyasasaurus the earliest dinosaur, because just six vertebrae and an upper arm bone are available to study, but numerous clues indicate the beast is, in fact, a dinosaur. "There was this big gap in the fossil record where dinosaurs should've been present and this fossil neatly fills that gap," the study co-author tells the BBC. Paleontologists have long believed dinosaurs existed in the Middle Triassic period, the era from which this fossil dates. If it is indeed a dinosaur, this fossil shows that dinosaurs started out "as a very insignificant group of reptiles" before exploding into the dominant life form on Earth millions of years later, the co-author says. Nyasasaurus probably stood upright and was seven to 10 feet long.