On the purported presence of fossilized collagen fibres in an ichthyosaur and a theropod dinosaur

摘要: Since the discovery of exceptionally preserved theropod dinosaurs with soft tissues in China 1990s, there has been much debate about nature filamentous structures observed some specimens. Sinosauropteryx was first non-avian to be described these structures, and remains one most studied examples. Despite a general consensus that represent feathers or feather homologues, few identify them as degraded collagen fibres derived from skin. This latter view based on observations low-quality images Sinosauropteryx, well suggestion because superficially similar are seen Jurassic ichthyosaurs they cannot feathers. Here, we highlight issues evidence put forward support this view, showing integumentary have misinterpreted sedimentary features preparation marks, errors led incorrect conclusions being drawn existence ichthyosaur Stenopterygius. We find is no idea two taxa fibres, confirm parsimonious interpretation fossilized look like homologues indeed homologues.