Cells, collagen fibrils and vessels in dinosaur bone.

Abstract

COLLAGEN has been found in mummified human remains several thousand years old, and in mastodon bones preserved under permafrost conditions. It has been stated that bone fragments after glacier preservation had all the appearances of a fresh bone1. Studies on Pleistocene bones have demonstrated that it is also possible to observe collagen and other organic materials in a fossil bone2,3. Electron micrographs of fossil bones of a deer-like animal from the Miocene (25 million years old) revealed collagen fibrils and the intact walls of canaliculi4. There have also been reports of striated muscle fibres, epithelial cells and melanophores being found in tissues of specimens from the Eocene (40 million years old) deposits of Geiseltal (eastern Germany)5. Furthermore, electron microscope investigations of patches of almost completely demineralized bone of a dinosaur from the Upper Trias (200 million years old), and the dermal armour of Devonian ostracoderms, have revealed a fibrillar structure, while a further examination of the same material showed a mixture of mineral and collagen patterns6. Analysis of fishes from the Middle Devonian (380 million years old) has indicated that degradation products of collagen can still be recognized. More recently7,8, it has been demonstrated that fossil dentine and bone-like tissues in Devonian ostracoderms can be decalcified and sectioned on a microtome. The presence in these tissues of polysaccharides as well as collagen has been indicated.