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Thumbs up to new sail-backed dinosaur!

Many of you probably know Iguanodon as being classically depicted as ‘The Fonz’ of the Cretaceous, always posing with its thumb sticking up*. But since its original description in 1825 by the infamous geologist, Gideon Mantell, the name of Iguanodon has become sort of a taxonomic plaything, being sliced and diced and knocked around in almost every way possible.

Ayyyyyy!
Ayyyyyy!

Hundreds of specimens were originally assigned to Iguanodon, and now scientists recognise that these represent numerous different species, each occupying a distinct time frame and geographical location. Some researchers even refer to them as the ‘cows of the Cretaceous’ as they’re commonly depicted as lumbering grazers, with nothing better to do than be prey for other dinosaurs..

Despite the impressive history of these dinosaurs, the fossil record still has the ability to surprise us with new discoveries. A new specimen from Castellón, Spain, from rocks dated to around 125 million years ago has been identified as a close cousin of Iguanodon, and named Morelladon beltrani in honour of Víctor Beltrán for his assistance at the dig sites. This dinosaur would have grazed the ancient forests of Europe, and came in at around 6 metres long and 2.5 metres tall (picture a super-sized cow..)

Map and photo of the site were Morelladon was excavated
Map and photo of the site were Morelladon was excavated

When it comes to dinosaur fashion, iguanodonts and their ornithopod relatives don’t exactly come across as trend-setters when compared to the gigantic sauropods and eagle-eyed theropod predators of the time. But relatively speaking, Morelladon was a bit of a flashy dresser! The vertebrae of the fossil possess tall dorsal spines, the bony projections coming off the top of the vertebrae that muscles attached to for spinal support. This would have given Morelladon a pretty cool sail, similar to other dinosaurs such as Spinosaurus, although not quite as big. What is interesting is that it shows that sails evolved multiple times in different dinosaur lineages, so must have conferred some sort of important advantage on them.

Spines of Morelladon, from Gasulla et al.
Spines of Morelladon, from Gasulla et al.

Why some dinosaurs developed these weird sails still remains a bit of a mystery for palaeontologists, at least until we get a time machine and go back to see how dinosaurs actually used them. It could perhaps have been used for identification purposes, or perhaps signalling, or maybe even similar to camels as a storage place for fat during periods of migration or food shortages.

Beautiful reconstruction of Morelladon, by Carlos de Miguel Chaves
Beautiful reconstruction of Morelladon, by Carlos de Miguel Chaves

The discovery of Morelladon continues to add evidence to the Early Cretaceous of Europe playing host to a highly diverse array of iguanodontians dinosaurs, often with multiple different species co-existing. Co-author Dr. Escaso said, “We knew the dinosaur fauna from Morella was similar to those of other contemporary European sites. However, this discovery shows an interesting rise of the iguanodontoid diversity in southern Europe around 125 million years ago.”

An analysis of the evolutionary relationships of Morelladon shows that it is most closely related to Iguanodon and Mantelliaurus species also from the same location in Spain. This suggests that in the Early Cretaceous of Europe, which would have been an island archipelago at the time, we had endemic pockets of dinosaurs living and evolving alongside one another.

One thing is for sure though, and that’s that even well-studied localities such as the Iberian peninsula still have many fossil surprises in store for us, each one contributing to our knowledge and understanding of dinosaur evolution.

The new study is published in PLOS ONE, so anyone can read about it!

* Someone totally needs to name an iguanodont species after The Fonz now

Citation: Gasulla JM, Escaso F, Narváez I, Ortega F, Sanz JL (2015) A New Sail-Backed Styracosternan (Dinosauria: Ornithopoda) from the Early Cretaceous of Morella, Spain. PLoS ONE 10(12): e0144167. doi:10.1371/journal.pone.0144167

Discussion
  1. How closely is Morelladon related to Ouranosaurus? Is there reason to think that sails developed multiple times not only among dinosaurs in general, but ornithopods in particular?

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