Spinosaurus skeleton Photp Credit: Kabacci via Flickr

Danielle Crowley looks at how our view of dinosaurs has changed in recent years.

[br]

Palaeontology has a long and distinguished history. Originally seen as the remains of dragons and giants, the first dinosaurs to be scientifically described were Megalosaurus and Iguanodon during the Victorian era, when dinosaurs really became part of the public psyche. Giant models were installed in London’s Crystal Park where they remain to this day. These two species in particular are a good example of how our understanding of these huge reptiles has changed.

The model Iguanodon looks like a massive, well, iguana, while Megalosaurus looks a bit like a bizarre crocodile. We now know that Iguanodon was more elegant than previously thought, with a spike on its thumbs instead of its nose, and that Megalosaurus was a bipedal carnivore.

These models and many early reconstructions depict dinosaurs as cold blooded, lumbering beasts. Many years later, we now have good reason to believe that they were active and warm blooded, like birds and mammals. This and the discovery that many dinosaurs were likely covered in feathers has changed our view of them for ever.

For some odd reason, this latter finding has ruffled feathers all over the world. Many people have complained that the idea of a feathered T-rex takes some of the awe and majesty away from it, and makes it less scary. This last point is a bit ridiculous, as anyone who has been up close to an ostrich will tell you.

Up until very recently, impressions of feathers were only found on fossils of dromaeosaurids (the most famous member of this group is the Velociraptor). Some of them had beautifully preserved wings, and others just had quill knobs on their arms, the anchor point for wing feathers.

But evidence for feathers has been found in some plant-eating dinosaurs, leading researchers to believe that all dinosaurs could potentially grow feathers. We even know what colour they may have been. Analysis of the fossils of Microraptor, a diminutive raptor, shows that its feathers were a glossy iridescent black.

By looking at modern dinosaurs, the birds, we think these feathers may have been used for insulation or display. Some species may have only had a few feathers, some were entirely covered and others could have only had them as youngsters.
Velociraptor is one of the ones that was most likely covered with fluff, and contrary to pop culture, it was about the size of a turkey. The raptors of Jurassic Park were based off Deinonychus, a larger but less well known species, hence why the name was changed.

Our knowledge of dinosaurian anatomy has gone through a makeover too. Spinosaurus, a carnivore famed for its iconic sail and size, was initially only known from bone fragments. New discoveries hint that it wasn’t a terrestrial hunter at all: it was the only aquatic dinosaur. These findings show that its hind legs were small, this combined with its bone structure (which is similar to modern aquatic vertebrates) hint at a creature that may have acted more like a crocodile than previously thought.

How we believe these animals behaved has also gone under scrutiny. The pachycephalosaurs are famed for their domed heads. We used to think that males butted heads rather like rams do today, but some scientists are now questioning that theory. The opinions of some is that their skulls would not have been able to sustain heavy blows of the sort imagined, and that the trauma of competing for mates this way would have killed them fairly quickly.

It’s very difficult to reconstruct dinosaur behaviour from a few fossils, nevertheless some remarkable insights have been suggested through careful analysis of what we do have. The remains of a T-rex was found that showed some terrible injuries, including a badly broken leg. Major injuries often kill carnivores, as unable to hunt they slowly starve to death – but this dinosaur had healed. Palaeontologists think that this T-rex had been fed by another, a far cry from the media’s perception of them.

These are only a few of the exciting revolutions that are continuously been unearthed in palaeontology, and it just goes to show that more can always be learnt about the magnificent animals that once roamed our planet even though they now only do so in our imaginations.