Earliest known dinosaur discovered

* Discovery puts dinosaur origins 10-15 mln years earlier

* Fossil sat in London's Natural History Museum for decades

* Has features unique to dinosaurs

LONDON, Dec 5 (Reuters) - Researchers have found what could

be the earliest known dinosaur to walk the Earth lurking in the

corridors of London's Natural History Museum.

A mysterious fossil specimen that has been in the museum's

collection for decades has now been identified as most likely

coming from a dinosaur that lived about 245 million years ago -

10 to 15 million years earlier than any previously discovered

examples.

The creature was about the size of a Labrador dog and has

been named Nyasasaurus parringtoni after southern Africa's Lake

Nyasa, today called Lake Malawi, and Cambridge University's Rex

Parrington, who collected the specimen at a site near the lake

in the 1930s.

"It was a case of looking at the material with a fresh pair

of eyes," Paul Barrett from the Natural History Museum, who

worked on the study, told Reuters. "This closes a gap in the

fossil record and pushes back the existence of dinosaurs."

The London fossil was studied by researchers in the 1950s

but no conclusion was reached and nothing was published, said

Barrett. "It was a mystery what it was ... It just became this

mythical animal."

Two features of the London fossil, together with a similar

sample subsequently spotted at the Iziko South African Museum in

Cape Town, are strong evidence that the animal belongs with the

dinosaurs, the researchers said.

The bone tissues in the upper arm show marks of rapid

growth, common in dinosaurs, and they also have a feature known

as an elongated deltopectoral crest that anchored the upper arm

muscles, a feature unique to dinosaurs.

"Although we only know Nyasasaurus from fossil fragments,

the anatomy of its upper arm bone and hips have features that

are unique to dinosaurs, making us confident that we're dealing

with an animal very close to dinosaur origin," said Barrett.

The researchers believe Nyasasaurus probably stood upright,

was a metre tall at the hip, 2-3 metres long from head to tail,

and weighed 20-60 kg.

When it was alive, the world's continents were joined in a

vast landmass called Pangaea, and the area of Tanzania where the

fossils were found would have been part of the southern Pangaea

that included Africa, South America, Antarctica and Australia.

Theorists have long argued there should have been dinosaurs

walking the Earth in the Middle Triassic period, which ended

about 237 million years ago, but until now the evidence has been

ambiguous, said Sterling Nesbitt at the University of Washington

in Seattle who led the study, published in the journal Biology

Letters.

"If the newly named Nyasasaurus parringtoni is not the

earliest dinosaur, then it is the closest relative found so

far," said Nesbitt.

"What's really neat about this specimen is that it has a lot

of history. Found in the '30s, first described in the 1950s ...

Now 80 years later, we're putting it all together."

The researchers plan further field work in Tanzania to find

more fossils and build a better picture of the animal's anatomy.

(Editing by Pravin Char)

MOST POPULAR IN SCI-TECH