A newly discovered reptile has led scientists “back to the drawing board” on feather evolution. Although existing 70 million years before the oldest fossil feathers, the Mirasaura grauvogeli has long outer layer structures which share similarities with feathers.
Originating from Grès à Voltzia in northeastern France, these reptiles had a large crest of plume-like structures, similar to how modern-day feathers look.
Palaeontologists at University College Cork (UCC), along with an international team of researchers from Germany, Italy, France and the USA, discovered the new species of fossil reptile from the Triassic period, which ended around 201 million years ago.
Professor Maria McNamara, leader of the UCC team and co-author of the study, told The Irish Times that the fossils were “originally discovered in the 1930s by an amateur, Louis Grauvogel”, who retained and protected them during the second World War.
RM Block
“They were kind of rediscovered by the family in an old drawer” and “donated to the Stuttgart museum of national history”, she said.
The team at UCC, made up of Prof McNamara, Dr Valentina Rossi and Dr Tiffany Slater, were asked to analyse the soft tissues of the specimen.
They examined the fossil’s outer layer using scanning electron microscopy and synchrotron X-ray analyses. The microscope used by the UCC team allowed them to examine the sample without applying any conductive coating (such as metal or gold), which usually improves the imaging of samples.
“Our electron microscope allows us to put in whole big fossils without coating them”, so “it doesn’t damage the specimens in any way”, said Prof McNamara.
The synchrotron X-ray analysis told the researchers of the chemical composition of the fossil. They found the fossil’s soft tissues were rich in copper, which is a common element associated with feathers.
The team also found the fossil tissue was rich in preserved melanosomes (cell organelles that contain melanin pigments), which are common in the feathers, skin, hair and internal organs of fossil and modern vertebrate animals.
They 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 Rossi. “We can therefore be confident that the Mirasaura structures share some common developmental features with feathers.”
Dr Slater said the discovery “forces us back to the drawing board for when feather-like structures first evolved”. She added: “Mirasaura reveals a deeper, more complex evolutionary story than we ever expected.”
Prof McNamara said this discovery “suggests there is the very real possibility other ancient reptiles were evolving very showy plumes”, which is “really exciting”.
She added that such discoveries would not be possible “if those specimens remained in private hands”.
“Because these specimens were donated to a public institution, it’s only then that they became accessible to scientists, and only because of that goodwill that we are able to make these really ground-breaking discoveries,” she said.
