The Press and Journal (Inverness, Highlands, and Islands)
Fossil clue to how birds got their feathers
Adinosaur known as the “parrot lizard” is helping scientists shed light on how reptile scales became bird feathers.
Psittacosaurus – a feathered plant-eater about the size of a large dog – roamed the forests of China, Russia and Mongolia between 135 million and 120 million years ago.
Palaeontologists have now discovered the creature had reptile-like skin in areas of the body without feathers.
Their findings, published in the journal Nature Communications, also revealed the dinosaur skin fossil they analysed was composed of silica, the same compound used to make glass.
Scientists at the University College Cork (UCC) in Ireland teamed up with experts in Nanjing University in China to analyse a fossil specimen of a juvenile Psittacosaurus unearthed in north-eastern China.
Dr Zixiao Yang, of UCC’s School of Biological, Earth and Environmental Sciences and the first author on the study, said the preserved skin cannot be seen with the naked eye.
He said: “Only under UV (ultraviolet) light is the skin visible, in a striking orange-yellow glow.
“What is really surprising is the chemistry of the fossil skin. It is composed of silica – the same as glass.
“This type of preservation has never been found in vertebrate fossils. There are potentially many more fossils with hidden soft tissues awaiting discovery.”
Feathers are highly complex structures that require specific skin adaptations. This makes feathered skin distinct from scaly, reptilian skin, the researchers said.
While feathers are thought to have evolved in dinosaurs, not much is known about the transition between the two skin types.
The researchers said their findings suggest Psittacosaurus’s skin had “zoned development”, with reptile-style scales in some areas and bird-like skin with feathers in others.
UCC’s Professor Maria McNamara said: “The evolution of feathers from reptilian scales is one of the most profound yet poorly understood events in vertebrate evolution.
“While numerous fossils of feathers have been studied, fossil skin is much more rare. Our discovery suggests that soft, bird-like skin initially developed only in feathered regions of the body, while the rest of the skin was still scaly, like in modern reptiles.
“This zoned development would have maintained essential skin functions, such as protection against abrasion, dehydration and parasites. The first dinosaur to experiment with feathers could therefore survive and pass down the genes for feathers to their offspring.”