Artist’s reconstruction of the feathered pterosaur Tupandactylus, showing the feather types along the bottom of the headcrest: dark monofilaments and lighter-coloured branched feathers.
Copyright © Bob Nicholls
It's difficult to keep track of all these 'non-existent' transitional fossils. Like London buses, you can wait for ages, then several will turn up together. One can't help but wonder how creationist find the time to ignore all of them.
Here for instance is one recently discovered fossil showing the transition from dinosaur to bird feathers, complete with evidence of pigmentation, showing that colour was important for display, even in these pterosaurs.
The discovery was made by An international team of palaeontologists led by Dr Aude Cincotta and Prof. Maria McNamara from University College Cork (UCC), Ireland and Dr Pascal Godefroit from the Royal Belgian Institute of Natural Sciences, together with colleagues from Belgium and Brazil.
The discovery was made when the team examined the 115 million year old fossilized headcrest of the pterosaur, Tupandactylus imperator, from north-eastern Brazil.
The news item from University College, Cork, give the detils:
More detail can be found in the abstract to the team's paper, published open access yesterday in Nature:This species of pterosaur is famous for its bizarre huge headcrest. The team discovered that the bottom of the crest had a fuzzy rim of feathers, with short wiry hair-like feathers and fluffy branched feathers.We didn’t expect to see this at all. For decades palaeontologists have argued about whether pterosaurs had feathers. The feathers in our specimen close off that debate for good as they are very clearly branched all the way along their length, just like birds today.
Dr Aude Cincotta, lead author School of Biological, Earth and Environmental Sciences
University College Cork, Cork, Ireland And Institute of Life, Earth and Environment
University of Namur, Namur, Belgium
The team then studied the feathers with high-powered electron microscopes and found preserved melanosomes – granules of the pigment melanin. Unexpectedly, the new study shows that the melanosomes in different feather types have different shapes.In birds today, feather colour is strongly linked to melanosome shape. Since the pterosaur feather types had different melanosome shapes, these animals must have had the genetic machinery to control the colours of their feathers. This feature is essential for colour patterning and shows that coloration was a critical feature of even the very earliest feathers.
Professor Maria McNamara. co-author School of Biological, Earth and Environmental Sciences
University College Cork, Cork, Ireland
AbstractEvidence such as this strongly suggests that, once feathers had evolved, presumably as insulation, evolution then had something to work on and plumage became important in display and maybe thermoregulation, even before it was adapted for flight in early birds. The pterosaurs were flying reptiles, but there is no suggestion that they flew like birds; they flew more like bats and could glide for long distances, probably using their crest to control flight and possibly to detect changes in air currents.
Remarkably well-preserved soft tissues in Mesozoic fossils have yielded substantial insights into the evolution of feathers1. New evidence of branched feathers in pterosaurs suggests that feathers originated in the avemetatarsalian ancestor of pterosaurs and dinosaurs in the Early Triassic2, but the homology of these pterosaur structures with feathers is controversial3,4. Reports of pterosaur feathers with homogeneous ovoid melanosome geometries2,5 suggest that they exhibited limited variation in colour, supporting hypotheses that early feathers functioned primarily in thermoregulation6. Here we report the presence of diverse melanosome geometries in the skin and simple and branched feathers of a tapejarid pterosaur from the Early Cretaceous found in Brazil. The melanosomes form distinct populations in different feather types and the skin, a feature previously known only in theropod dinosaurs, including birds. These tissue-specific melanosome geometries in pterosaurs indicate that manipulation of feather colour—and thus functions of feathers in visual communication—has deep evolutionary origins. These features show that genetic regulation of melanosome chemistry and shape7,8,9 was active early in feather evolution.
Cincotta, Aude; Nicolaï, Michaël; Campos, Hebert Bruno Nascimento; McNamara, Maria; D’Alba, Liliana; Shawkey, Matthew D.; Kischlat, Edio-Ernst; Yans, Johan; Carleer, Robert; Escuillié, François; Godefroit, Pascal
Pterosaur melanosomes support signalling functions for early feathers
Nature (2022). https://doi.org/10.1038/s41586-022-04622-3
Copyright: © 2022 The authors. Published by Springer Nature Ltd.
Open access
Reprinted under a Creative Commons Attribution 4.0 International license (CC BY 4.0)
No comments :
Post a Comment
Obscene, threatening or obnoxious messages, preaching, abuse and spam will be removed, as will anything by known Internet trolls and stalkers, by known sock-puppet accounts and anything not connected with the post,
A claim made without evidence can be dismissed without evidence. Remember: your opinion is not an established fact unless corroborated.