Another feather in university’s cap

A significant breakthrough has been made which completely disrupts the view of the evolution of skin and feathers in reptiles.

An international team of researchers including palaeontologists at UCC have discovered a new species of fossil reptile from the Triassic period that had a large crest made of complex plume-like structures - long before modern-type feathers evolved.

The 247 million year old fossil, Mirasaura Grauvogeli from the Grès à Voltzia locality in northeastern France, had a bizarre showy plume of long outer layer structures. These share similarities with feathers, despite existing 70 million years before the oldest fossil feathers.

The research, published on Wednesday in the journal Nature, includes UCC palaeontologists Prof. Maria McNamara, Dr Valentina Rossi and Dr Tiffany Slater. The study was led by scientists Dr Stephan Spiekman and Prof. Dr Rainer Schoch from the State Museum of Natural History Stuttgart, Germany, along with an international team from Germany, Italy, France and the USA.

The UCC team analysed the fossil outer layer - or integumentary - structures using scanning electron microscopy and synchrotron X-ray analyses. The fossil tissue is rich in preserved melanosomes – cell organelles that contain melanin pigments – that are common in skin, hair, feathers and internal organs of fossil and modern vertebrate animals.

The UCC team discovered that the melanosomes in mirasaura are similar in shape to those in feathers, but not mammal hair or reptilian skin.

“We know that in modern animals, melanosome shape is closely linked to tissue type,” said Dr Valentina Rossi. “We can therefore be confident that the mirasaura structures share some common developmental features with feathers.”

Unlike feathers in modern birds, however, the mirasaura structures lack branching, showing instead a simple long, medial feature that superficially resembles the shaft of modern bird feathers.

“We were looking in the right time window, but we were shocked to find long integumentary structures in a completely different group of ancient reptiles,” says Prof. Maria McNamara, leader of the UCC team and coauthor of the study.

Co-author Dr Tiffany Slater said: “It’s amazing - this creature forces us back to the drawing board for when feather-like structures first evolved. Mirasaura reveals a deeper, more complex evolutionary story than we ever expected.”