T.rex Tuesday - An American T.rex Near London

A cast of Black Hills Institute's Stan shares the focal point of the Oxford University Museum of Natural History with an Iguanodon in the classic - and now disproven - tail-dragging pose. Photos by the author.

A cast of Black Hills Institute's Stan shares the focal point of the Oxford University Museum of Natural History with an Iguanodon in the classic - and now disproven - tail-dragging pose. Photos by the author.

What a week it has been! And now it's T.rex Tuesday again! We're shaking off the winter cold (I had to put on a sweatshirt before going outside here in California) by thinking about another grand adventure from last year. Certainly one of the more unique visits on the 2017 T.rex Road Trip was the Oxford University Museum of Natural History in Oxford, England. There were so many things that I was excited to see at OMNH, that a cast of Black Hills Institute's venerable "Stan" almost seemed like an afterthought. But aside from adding the usual rex appeal, Stan serves another important purpose.

As demonstrated on the mounted Iguanodon skeleton in front of it, scientists assumed for many years early on that bipedal dinosaurs stood upright, with their tails dragging behind them. There's plenty of illustrations and depictions to that end, and many museum dinosaurs were so mounted. The reasons are pretty straightforward - to study what once was, scientists also compare and contrast it to what we see today. But as early as the late 1960's, it was proposed that bipedal dinosaurs actually used their tails for balance, keeping them out behind their body rather than laying on the ground.

The first evidence for that comes from the simplest of places - discovered trackways. Oxford's museum includes casts from the tracks of a Megalosaurus, the first dinosaur to be discovered. The tracks, like virtually all other dinosaur trackways thus discovered, are missing a conspicuous feature - drag marks from the tail. Analysis of muscle structures based on attachment marks on the fossils, along with other study, has revealed that dinosaurs like Tyrannosaurus rex weren't equipped to take the tail dragging stance - their neck muscles couldn't support their heads, among other things. In the case of the Oxford Iguanodon, the tail actually had to be broken in order to allow it to take on the tail dragging posture.

Many museums have hastened to re-pose their dinosaurs to adopt more correct postures. For whatever reason, the museum's Iguanodon - which was excavated in Belgium in 1878 - still maintains its kangaroo-like pose. With Stan posed properly behind, it provides one of the best opportunities to compare the early thought with later scientific discoveries.

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