A bedrock tenet of paleontology holds that fossils of dinosaurs and other long-gone beasts consist strictly of inorganic remains. Organic substances such as blood are simply too fragile to persist across millions of years. Or so scientists thought. A growing body of evidence indicates that organic material such as blood vessels and cells can in fact survive in fossils, as this article in the December 2010 issue explains.

Below is a list of online resources about discoveries of putative dinosaur soft tissues and the controversy they have engendered.

*Preservation of Biomolecules in Cancellous Bone of Tyrannosaurus rex, Mary H. Schweitzer et al.’s 1997 Journal of Vertebrate Paleontology report on their discovery of blood cell-like structures in T. rex bone

*Beta-Keratin Specific Immunological Reactivity in Feather-like Structures of the Cretaceous Alvarezsaurid, Shuvuuia deserti, Mary H. Schweitzer et al.’s 1999 paper in the Journal of Experimental Zoology describing the preservation of apparent feather fibers in a small carnivorous dinosaur

*Soft-Tissue Vessels and Cellular Preservation in Tyrannosaurus rex,Mary H. Schweitzer et al.’s 2005 Science paper on the discovery of blood vessels, collagen and bone cells in a 68-million-year-old T. rex

*Scientists Find Soft Tissue in T. rex Fossil, Scientific American.com news story on the above paper

*T. rex Blood? Expert Q&A, Nova ScienceNow interview from 2007 with Schweitzer on her discovery of T. rex cells and blood vessels

*Protein Sequences from Mastodon and Tyrannosaurus rex Revealed by Mass Spectrometry, John Asara et al.’s 2007 Science report on the sequencing of ancient proteins

*Was T. Rex Really King of the Lizards—or Just a Big, Carnivorous Chicken? Scientific American.com story on the above paper

*Dinosaurian Soft Tissues Interpreted as Bacterial Biofilms, Thomas G. Kaye et al.’s  2008 paper  in PLoS ONE, arguing that alleged ancient soft tissues are actually “slime” produced by microbes

*Presumed dinosaur flesh may just be bacterial sludge, Scientific American.com news story on the above paper

*Biomolecular Characterization and Protein Sequences of the Campanian Hadrosaur
B. Canadensis, Mary H. Schweitzer et al.’s 2009 report in Science on the recovery and sequencing of proteins from an 80 million-year-old duckbill dinosaur fossil

*Scientists Flesh Out Fossilized Tissues from Mummified Dinosaur, Scientific American.com news story on the discovery of a 65 million-year-old duckbill dinosaur containing mummified soft tissues and organic compounds