Did pterosaurs also have feathers – similar to some species of dinosaurs? This question, which has so far been hotly debated, now seems to have been resolved: in addition to traces of hair-like fibers, paleontologists have also found branched structures in pterosaur fossils that are similar to those found in contemporaries. feathers of the birds of the day. They also found evidence that these feathers and the areas of skin surrounding them were pigmented and therefore possibly also serving for show effects. According to the researchers, the study sheds new light on the evolution of feathers and their functions.
In the case of dinosaurs, it is now clear that many species already had complex plumage. In some finds, even the fine structure of their feathers was clearly visible. What distinguished these structures from hair was their complex branching. Accordingly, some representatives of the dinosaurs only had fluff-like plumage to keep them warm – but there were also more complex feather shapes that likely played a role in mating behavior. At some point, some dinosaurs also developed feathered wings that they could use to soar into the air. Then they became the ancestors of today’s birds.
Traces of pterosaur feathers
So it was obvious that dinosaurs were the “inventors” of feathers. But this assumption was questioned in 2018: Paleontologists found evidence of branched feather structures in addition to the already known hair-like structures in pterosaurs. The decisive aspect is that pterosaurs were not representatives of dinosaurs, but only relatives – the lines of development of both groups split more than 250 million years ago. So, the findings of feathers in flying reptiles are something special. However, the structures discovered so far may also have been misinterpreted, which has been criticized by some palaeontologists. However, scientists led by Aude Cincott of University College Cork are now presenting new, very clear evidence of the existence of pterosaur feathers.
The finds come from the study of the particularly well-preserved head of Emperor Tupandactylus from Brazil. These representatives of pterosaurs had a wingspan of about five meters and had a particularly distinctive crest on their heads that was probably an intraspecific display element. As reported by Cincott and her colleagues, the traces of fine structures on the back of this ridge aroused particular interest in them. To discover further details, they examined the area under an electron microscope.
Their findings show that the animal had a feather crown on the underside of the crest: in addition to hair-like fibers, scientists also found traces of fluffy, branched structures with characteristics similar to those of bird feathers. “Paleontologists have been debating for some time whether pterosaurs have real feathers. The feathers of our specimen end this debate for good, as they are clearly branched along their entire length, as in modern birds, ”says Cincotta.
Colorful plumage is distinguished
In the course of their research, paleontologists also discovered traces of the so-called melanosomes in the feathers and debris of the animal’s skin. These are the structures in which the melanin pigment is found. Detailed studies have also shown that the melanosomes in the fibers, feathers and skin vary in shape. “In modern birds, the color of the plumage is closely related to the shape of melanosomes,” explains co-author Maria McNamara of University College Cork. “Since the types of pterosaur feathers had different melanosome shapes, these animals must have had the genetic machinery to produce different feather colors. This feature is crucial for color matching, ”says McNamara.
In particular, research results suggest that the Tupandactylus emperor’s head was not only impressively shaped, but also colored: the colors and patterns created by the feather structures could also play a role in the intraspecific communication of these pterosaurs. Thus, there are clear parallels to the findings for certain species of dinosaurs. This, in turn, is an important clue as to the origin of feather evolution: if pterosaurs also had structures, it is understandable that the innovation came from the common ancestor of pterosaurs and dinosaurs.
Accordingly, the creature may have produced the first feather-like structures around 250 million years ago – presumably initially to keep warm. However, the role of feathers as elements of visual communication may also have deep evolutionary roots. “The new research results may now lead to a reorientation towards the study of the insulating capacity of feathers, which was probably the main reason behind their development – and their subsequent use as signaling structures,” writes Michael Benton of the University of Bristol in a commentary on the study.
Source: University College Cork, Article: Nature, doi: 10.1038 / s41586-022-04622-3