Australia: The Land Where Time Began

A biography of the Australian continent 

It is the oldest known member of the Alvarezsauroidea superfamily, being 63 million years older than the next earliest member of the group known, and 15 million years older than Archaeopteryx. It is 160 million years old, from the earliest Late Jurassic. It was found in the Shishugou Formation, Junggar Basin, in northwestern China.

Their name derives from the single huge claw that ends each arm. It has been suggested that they were specialised for digging. The theropod dinosaurs of the Alvarezsauroidea superfamily have a number of characters similar to birds, such as short arms, a keeled sternum, 3 toes. They appeared to be so bird-like that the first specimens to be studied were at first thought to be archaic birds. H. sollers is a transitional form, early in the evolution of the line leading to the Alvarezsauroidea dinosaurs, with their bizarre hands, from earlier theropod dinosaurs. Its claw is a bit shorter, and its arms are longer than the later Alvarezsauroidea dinosaurs. At up to 7.5 ft long it is large for a member of this group, indicating that the line underwent a process of miniaturisation over their evolutionary history.

Links

• New large-clawed Jurassic dinosaur sheds light on elusive lineage
• DinoData
• Wikipedia

Sources & Further reading

• Feathered Dinosaurs: the Origin of Birds, John Long and Peter Schouten, CSIRO Publishing