Amazing stuff!
"... Palaeontologists ... have found that some feathered dinosaurs had scaly skin like reptiles. Their results are based on an analysis of a new specimen of the feathered dinosaur Psittacosaurus. ...
There are up to 12 known species of Psittacosaurus – the most of any dinosaur genus. One specimen made waves when it was discovered with preserved filaments on its tail – early feathers. ...
By the time Psittacosaurus came around, many dinosaurs already had feathers. In fact, some palaeontologists suggest that most, if not all, dinosaurs had at least some feathers by the time of the mass extinction event 66 million years ago. ...
A new Psittacosaurus fossil specimen found in northeastern China, dated to between 133 and 120 million years ago, was analysed by the UCC team, along with researchers from Nanjing University in China.
The team used ultraviolet light to identify patches of preserved skin. Further X-ray and infrared analysis revealed spectacular detail of the cell structure of the fossilised skin. ..."
From the abstract:
"Fossil feathers have transformed our understanding of integumentary evolution in vertebrates. The evolution of feathers is associated with novel skin ultrastructures, but the fossil record of these changes is poor and thus the critical transition from scaled to feathered skin is poorly understood. Here we shed light on this issue using preserved skin in the non-avian feathered dinosaur Psittacosaurus. Skin in the non-feathered, scaled torso is three-dimensionally replicated in silica and preserves epidermal layers, corneocytes and melanosomes. The morphology of the preserved stratum corneum is consistent with an original composition rich in corneous beta proteins, rather than (alpha-) keratins as in the feathered skin of birds. The stratum corneum is relatively thin in the ventral torso compared to extant quadrupedal reptiles, reflecting a reduced demand for mechanical protection in an elevated bipedal stance. The distribution of the melanosomes in the fossil skin is consistent with melanin-based colouration in extant crocodilians. Collectively, the fossil evidence supports partitioning of skin development in Psittacosaurus: a reptile-type condition in non-feathered regions and an avian-like condition in feathered regions. Retention of reptile-type skin in non-feathered regions would have ensured essential skin functions during the early, experimental stages of feather evolution."
Fig. 2: Preserved skin of Psittacosaurus (NJUES-10).
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