First Venezuelan dinosaur was a social animal

06 August 2014

The first dinosaur found in northern South America reveals the earliest example of social behaviour in a bird-hipped species.

A group of dinosaur fossils discovered in Venezuela has been identified as a new species by an international team of researchers including Museum expert Dr Paul Barrett.

Laquintasaura venezuelae is named after the La Quinta Formation of rocks in the Andes Mountains, where the 201-million-year-old fossils were found. Until now scientists had assumed that the region was uninhabited by dinosaurs as it was surrounded by large deserts.

L. venezuelae walked on its hind legs and was about the size of a small dog. It is thought to have been largely herbivorous, but might have also eaten insects or other small prey.

Surprising firsts

The fossil find included bones from at least four L. venezuelae, with individuals ranging in age from three to approximately 12 years old. This group is the earliest evidence of social behaviour among bird-hipped dinosaurs.

‘It’s always exciting to discover a new dinosaur species but there are many surprising firsts with Laquintasaura’, said Dr Barrett. ‘It is fascinating and unexpected to see they lived in herds, something we have little evidence of so far in dinosaurs from this time.’

Early bird-hipped species

There are two main groups of dinosaurs. Bird-hipped dinosaurs include herbivores such as Triceratops and Iguanodon. Lizard-hipped dinosaurs include all carnivorous dinosaurs as well as huge herbivores such as Brachiosaurus.

By measuring the residual radioactivity of tiny crystals in the rock surrounding the new find, the fossils’ age was accurately measured as 201 million years old. This makes L. venezuelae a rare early member of the bird-hipped group.

Mass extinction

The accurate dating of L. venezuelae also helps define an early period of dinosaur evolution. ‘L. venezuelae lived very soon after the major extinction at the end of the Triassic Period, 200 million years ago, showing dinosaurs bounced back quickly after this event’, said Dr Barrett.

Relatively few early bird-hipped dinosaurs have been found, so L. venezuelaea will help to fill in the gaps, according to Prof Marcelo Sánchez-Villagra from the University of Zürich, a co-author on the paper announcing the discovery.

‘The history of bird-hipped dinosaurs is still very patchy as so few of them have been found. This early species plays a key role in our understanding of the evolution, not only of this group, but of dinosaurs in general.’

  • by Sam Rae
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