Tuesday, 5 May 2009

Red in tooth and claw

There's a very rich Cretaceous site in the Kem Kem area of Morocco. Lots of dinosaur teeth are found there. Lots. The stone is mostly a crumbly, pinkish sandstone and while the teeth and bones found are quite fragile, the preservation can be remarkably good. There are a few animals found in the stratigraphy - the T.rex-like Carcharodontosaurus, the sauropod Rebacchisaurus, the raptor Deltadromeus, crocodiles and a pterosaur, Sirrocopteryx.

For me, though, the most notable find of this area is Spinosaurus aegyptiacus. Spinosaurus was originally found and named in Egypt in the early 1900s but the original holotype was destroyed during WWII. Other examples have been found in Egypt and Tunisia, but the Kem Kem churns out bucketloads of Spino teeth and some claw and bone material.

Spinosaurus is thought to be the biggest carnosaur found so far. Estimates put the weight between 7 and 9 tonnes, and between 50 and 60 feet in length. It is related to the Baryonyx of England and Brazil's Irritator, has a long, crocodilian snout, simple, smooth teeth with slight vertical ridges and a large 'sail' on its back.

The skull and jaws show a long muzzle with raised nostrils - a little like crocodiles. It's thought Spinos may well have eaten fish as well as smaller dinosaurs and probably scavenging. More recent research has suggested that the shape of the extended vertebral bones that form the 'sail' is consistent with those in modern buffalo with large fatty humps on their backs. Spinos may have had more of a lump than a sail. Not quite so dashing.

Bit of a side note here. As with many dinosaur genera, there are arguments about many aspects - range in size, purpose of sail/hump, palaeoenvironment, etc. Recently it was realised that modelling of dinosaurs and creation of assemblages from articulation of bones etc left too little allowance for intervertebral discs. With a more realistic spacing of vertebra, most dinsoaurs may well have actually been much bigger than previously thought.

Spinosaurus was one of the stars of the Jurassic Park series, appearing in the third film to smash the T.rex about, and bite his face off. Bragging rights to the Spino.

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