Abstract

[CANCELLED DUE TO ILL HEATLTH ]

For decades it was assumed that all dinosaurs had scaly skin, like that of their living reptilian relatives, an idea backed up by spectacular discoveries of complete ‘mummified’ hadrosaurs. However, the realisation that birds were direct descendants of small, meat-eating dinosaurs led some to speculate that feathers could have presaged flight and might be found in close bird relatives. Beginning in 1996, a series of spectacular fossils was unearthed in ancient Cretaceous lake deposits from northwest China. These animals, with exquisite skin preservation, showed – without question – that many non-avian dinosaurs possessed a variety of feather types. However, as direct evidence of skin structure is available only from rare Lagerstätte deposits that preserve soft tissue information, which are formed under unusual geological conditions, it’s unclear when feathers first appeared. Moreover, it’s not known if feathers characterised all dinosaurs or just sub-groups thereof. Other discoveries of feather-like structures across the dinosaur evolutionary tree, and in close dinosaur relatives like the flying reptiles (pterosaurs), have further muddied the picture. A combination of evolutionary modelling, developmental biology, geology and palaeontology is being used to try and answer this question, which is fundamental to understanding why and how feathers appeared.