IGUANODON
For this edition I thought we'd take a look at one of the Dinosaurs that first captured my imagination as a child - Iguanodon.
First discovered by Gideon Mantell in Sussex, England in the 1820's, the story of Iguanodon's discovery and classification is one of the more famous in palaeontology.
Initially, only some teeth were found (allegedly by Mantell's wife).
A few years later, a more complete skeleton was found, but as palaeontology was a very new science at the time, Mantell's reconstruction of the skeleton was initially incorrect - he imagined the creature as a gigantic Iguana, with a rhinoceros-like horn on it's snout.
Later on, as better specimens were found, Mantell's mistake would become obvious - The "Horn" was in fact part of the foreleg, acting as a spike in the thumb position.
(One day, we'll focus more on this story, and how dinosaurs become classified)
Iguanodon was a herbivorous ornithopod from the early Cretaceous period, that was about 10 metres long and weighed an impressive 3 tons.
One of only a few dinosaur species able to move either bipedally or on all fours, enabling it to graze on the ground or reach food higher up in the trees.
The hand of Iguanodon is one of the more fascinating parts of any dinosaur species, and is wonderfully adapted to Iguanodon's habitat and lifestyle. The central 3 digits are relatively immobile, and grouped together, forming a hoof-like appendage not unlike that of modern-day ungulates. This would have allowed it to bear it's great weight when moving on all fours.
The 4th digit, equivalent to our pinky finger, was very dextrous, acting almost like an opposable thumb. (an evolutionary adaptation which is rare - even today, millions of years later). Allowing the Iguanodon to grasp food with it's hand, rather than using it's mouth would have allowed for greater care to be taken while eating, and possibly for manipulating other objects in the creature's habitat.
The most striking feature of the hand though, is the giant thumb spike. This would have been used mainly as a defensive weapon against the large predators of the day, and with devastating effect - in a way it was comparable to the sickle-like claws of Deinonychus and similar "raptor" species.
So as you can see, Iguanodon is an important and fascinating find, because even though the initial discovery was thought to be an extremely large Iguana, the reality of the species turned out to be even more spectacular.
