Sunday, 3 March 2013

A New Species Of Tiny Dinosaur

The newly discovered, late Cretaceous fossil of Yulong mini
Most people think of dinosaurs as big, brash creatures which roamed across the supercontinent of Pangaea, trampling forests whilst shaking the ground beneath them. The name Seismosaurus is nothing short of a testament to size. Sauroposeidon is named after the Greek god Poseidon, the god of earthquakes as well as the oceans. Yet not all dinosaurs were giants.

Instead of of the sound of trampled tropical forests, branches echoed with the cries and rustles of miniature, bird-sized creatures no more threatening than a crow. The newest of these diminutive dinosaurs is Yulong mini, discovered earlier this year at the late Cretaceous Qiupa Formation in the Henan Province in central China. It is one of the smallest recorded members of its group.

'Yulong looks like chicken with a tail,' said lead author of the paper published on the specimen Junchang Lü. 'Its behaviour was similar to living birds. Based on the primitive oviraptors such as Caudipteryx, Yulong should be feathered, although we could not find feathers due to the poor preservation condition.' Despite this, the researchers were still able to extract a large amount of information from the fossil.
An artist's impression of Yulong mini.

Specimens of hatchlings were found in the same formation as adults of the species. Yet a lack of proximity between the juveniles and the adults suggests that there was very little parental care in the species and the young had to fend for themselves from birth. Indeed, the jaws, even in hatchlings, were tough and capable of coping with an array of foodstuffs from meat, nuts to molluscs and eggs.

The oviraptorids were notorious egg feeders and the beak-shaped jaw of Yulong suggests that it too was adapted to cope with the hard shells of dinosaur eggs.

What is interesting is that it lacked the long legs of other members of its group, restricting its speed capacity. That combined with its diminutive stature means that it was most likely a herbivore. Though probably a scavenger on the side. Yulong was also the prey of other dinosaurs. Larger carnivores were found in the formation and would have occupied the space at the top of the ecosystem's food web.

The discovery of Yulong suggests something more incredible: that multiple groups of dinosaurs were following an evolutionary pathway which led to increasingly more bird-like forms. In essence, the different strands of the dinosaur family were converging on the birds, lending credence to the theory of convergent evolution. While it may be just that, a theory, if it is proved correct, it has major implications for the history of life on Earth and for life itself. Maybe there is some grand, overarching evolutionary design. The presence of Yulong scratches tantalisingly at the prospect.