Tuesday, August 31, 2010

Vintageosaurus mistakeii

Reconstruction of Laelaps (now known as Dryptosaurus) - by Edward Drinker Cope - possessing a typical (at the time) vertical posture, slouching head and useless arms. Image from Love in the time of Chasmosaurus

We occasionally make mistakes. Everyone can think of at least one major mistake they've made during their career (undoubtedly we make a couple in our personal lives which we may or may not wish to recall). But I want to look into some memorable vintage palaeo mistakes. . . the ones generally made when there is nothing in the known world (19th century known world) that can be comparable to the discovery of massive "lizard bones":

Iguanodon
Most people will recognise this dinosaur more than the first palaeo reconstruction mistake, Megalosaurus. The first reconstruction of iguanodon was the huge iguana-like statue which still stands at Crystal Palace, south London, by Benjamin Waterhouse Hawkins. The "thumb spike" was placed on the tip of the snout, creating a more lizard-like appearance. In some aspects, Hawkins' iguanodon resembles a horned, very toothy chameleon.
The initial reconstruction of Iguanodon by Hawkins, and the current corrected version by Raul Martin.

Apatosaurus (formerly Brontosaurus)
The
Apatosaurus went through many changes, but one of the more notable was the correction of its skull. For many years until 1975, the poor sauropod borrowed the skull of a distantly related cousin, Camarasaurus - more closely related to Brachiosaurus. The contrast in the two skull types are quite astounding.


Left is the Camarasaurus skull, which for years was placed upon the body of "Brontosaurus", the skull on the right is that of a Diplodocus, a close relative of Apatosaurus (NE: Brotosaurus) and displays what the skull of Apatosaurus should have been like. Image from Taylor, M.P., Wedel, M.J., Naish, D. 2009. Head and neck posture in sauropod dinosaurs inferred from extant animals. Acta Palaeontologica Polonica, 54(2): 213-220

Posture, poise and grace

For most dinosaurs, the position of the legs and the weight-bearing stance was often incorrect.
Tyrannosaurus, Iguanodon, Triceratops, Stegosaurus and even large sauropods have all fallen at the unbalanced positioning of their limbs and tails. Tyrannosaurus, for example, for many years had been depicted as near vertically erect like an alert meerkat and balanced precariously on its tail (which dragged along the floor similarly to sauropods depicted around the early 20th century). In the case of the sauropods, (such as Diplodocus) they were occasionally illustrated with bow-legs; dragging their enormous bulk through the dirt, long tail limp behind them. Due to this hefty burden, most sauropods were placed in an aquatic setting to allow them more buoyancy. Providing evidence in the fact that poor teaching and a long-standing reliance in religion and Creationism doesn't achieve results in reality.

The reason for bringing up some of the errors in palaeontology (and particularly reconstructions) is in showing that when first uncovered, after the initial analysis and subsequent recording of characteristics and features, not everything about a specimen will be correct. More often than not, since science is forever updating its knowledge and techniques, things which may not have been considered important may, in fact, turn out to be the exact source of information which could completely alter the definition of that specimen... as an example, I turn your attention to BMRP 2002.4.1 "Jane"... (in my heart, always a Nanotyrannus), or maybe the example of the absorption of Stygimoloch and Dracorex as individual species into different growth stages of Pachycephalosaurus would be for better understanding.

No comments:

Post a Comment