Tiny dinosaur species discovered

21 October 2009

Dinosaurs are known for their huge size, but a new species discovered in Colarado, USA, is notable for being tiny. The miniature creature from the Jurassic period is described in Proceedings of the Royal Society B this week.
Weighing in at less than a kilogram and only 65 to 75 cm long, Fruitadens haagarorum is one of the smallest known dinosaurs and the smallest found in North America. It was identified by an international team of scientists, led by Dr Richard Butler of the Bavarian State Collection for Palaeontology, Munich, Germany, and the Natural History Museum in London.

It was found in a series of rocks called the Morrison Formation that has been studied for 130 years but still holds secrets. Dr Butler says "It is still possible to discover completely unique and remarkable species. If dinosaur ecosystems were that diverse, who knows what astonishing beasts are waiting for us to discover?"

Painstaking examination of the leg bones allowed the team to work out the fossils were from young adults that were nearly fully grown. Fruitadens had an unusual smile, with canine like teeth in the lower jaw and leaf shaped teeth behind, suggesting it may have fed on both plants and animals.

Dinosaurs are traditionally divided into two groups, the carnivores which includes the very smallest species, and the predominantly plant eating ornithischians, which range from just over a metre to a lumbering 17 m length.  Fruitadens cuts across these divisions, as the smallest known omnivore. It is a strategy that must was successful, as the nimble Fruitadens was around for 100 million years.