UCC palaeontologists have discovered a new way of reconstructing the anatomy of ancient vertebrate animals by analysing the chemistry of fossilized melanosomes from internal organs.
Until recently, most studies on fossil melanin have focussed on the skin and feathers, as here the pigment is linked to visible colour. Unexpectedly, the new study shows that melanin is also abundant in internal organs of modern amphibians, reptiles, birds and mammals, and their fossil counterparts.
The study, published today in the journal Proceedings of the National Academy of Sciences USA, is led by UCC’s Valentina Rossi and her supervisor Dr Maria McNamara in collaboration with an international team of chemists from the USA and Japan. The team used cutting-edge synchrotron techniques to analyse the chemistry of the fossil and modern melanosomes using X-rays.
The team made the initial discovery of internal melanosomes last year on fossil frogs. ‘After the pilot study, we had a hunch that these features would turn out to be more widespread across vertebrates. But we never guessed that the chemistry would be different in different organs,’ said Ms Rossi.
‘This discovery is remarkable in that it opens up a new avenue for reconstructing the anatomy of ancient animals. In some of our fossils we can identify skin, lungs, the liver, the gut, the heart, and even connective tissue’ said senior author Dr McNamara. ‘What’s more, this suggests that melanin had very ancient functions in regulating metal chemistry in the body going back tens, if not hundreds, of millions of years.’
This study would not have been possible fifteen years ago: ‘The advent of new synchrotron X-ray analysis techniques allows us to harness the energy of really fast-moving electrons to detect minute quantities of different metals in the melanosomes,’ said collaborator Sam Webb. ‘The fossils are so well preserved that even the melanin molecule can be detected,’ said collaborators Sho Ito and Kazumasa Wakamatsu from Japan.
The study was published today in PNAS: Rossi, V., McNamara, M.E., Webb, S., Ito, S., Wakamatsu, K., 2019. Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates. PNAS, in press. DOI: doi.org/10.1073/pnas.1820285116.
See below for news items on the study:
https://soundcloud.com/kfmradiokildare/kildare-today-21-08-19-hour-2 (Valentina’s interview starts at 25:20!)
Maria gave an interview that is featured in a new audiobook called “A Grown Up Guide To Dinosaurs”. She appears in episode 3 – “Feathered Freaks”! A section of her interview can be previewed here (or by clicking on the image below), and the whole audiobook can be accessed here with an Audible account.
Maria’s co-authored paper ‘, Experimental analysis of soft-tissue fossilization: opening the black box’, published in the journal Palaeontology in 2018, is one of the top downloaded articles in Palaeontology in 2017-2018. Congratulations to Maria, first author Prof. Mark Purnell and all co-authors!
FREE DOWNLOAD UNTIL 9th OCTOBER 2019: https://authors.elsevier.com/c/1ZbLdcZ3Wk9ST.
New research suggests that feathers arose 100 million years before birds. This changes how we look at dinosaurs, birds, and pterosaurs, the flying reptiles. It also changes our understanding of feathers themselves, their functions and their role in some of the largest events in evolution.
The new work, published in ‘Trends in Ecology & Evolution’ combines new information from palaeontology and molecular developmental biology. The key discovery came earlier in 2019, when feathers were reported in pterosaurs – if the pterosaurs really carried feathers, then it means these structures arose deep in the evolutionary tree, much deeper than at the point when birds originated.
‘The oldest bird is still Archaeopteryx first found in the Late Jurassic of southern Germany in 1861, although some species from China are a little older,’ says Mike Benton of the University of Bristol, who led the study. ‘Those fossils all show a diversity of feathers – down feathers over the body and long, vaned feathers on the wings. But, since 1994, palaeomntologists have been contending with the perturbing discovery, based on hundreds of amazing specimens from China, that many dinosaurs also had feathers.’
‘At first, the dinosaurs with feathers were close to the origin of birds in the evolutionary tree,’ says Baoyu Jiang from the University of Nanjing, a co-author. ‘This was not so hard to believe. So, the origin of feathers was pushed back at least to the origin of those bird-like dinosaurs, maybe 200 million years ago.’
‘Then, we had the good fortune to work on a new dinosaur from Russia, Kulindadromeus,’ says Maria McNamara from the University of Cork, also a co-author. ‘This dinosaur showed amazingly well preserved skin covered with scales on the legs and tail, and strange whiskery feathers all over its body. What surprised people was that this was a dinosaur that was as far from birds in the evolutionary tree as could be imagined. Perhaps feathers were present in the very first dinosaurs.’
‘I came in at this point,’ says Danielle Dhouailly from the University of Grenoble, also a co-author. ‘I work on the development of feathers in baby birds, and especially their genomic control. Modern birds like chickens often have scales on their legs or necks, and we showed these were reversals: what had once been feathers had reversed to be scales. In fact, we have shown that the same genome regulatory network drives the development of reptile scales, bird feathers, and mammal hairs. Feathers could have evolved very early.’
‘The breakthrough came when we were studying two new pterosaurs from China,’ says Baoyu Jiang. ‘We saw that many of their whiskers were branched. We expected single strands – monofilaments – but what we saw were tufts and down feathers. Pterosaurs had feathers.’
‘This drives the origin of feathers back to 250 million years ago at least,’ says Mike Benton, ‘the point of origin of pterosaurs, dinosaurs and their relatives. The Early Triassic world then was recovering from the most devastating mass extinction ever, and life on land had come back from near-total wipeout. Palaeontologists had already noted that the new reptiles walked upright instead of sprawling, that their bone structure suggested fast growth and maybe even warm-bloodedness, and the mammal ancestors probably had hair by then. So the dinosaurs, pterosaurs and their ancestors had feathers too. Feathers then probably arose to aid this speeding up of physiology and ecology, purely for insulation. The other functions of feathers, for display and of course for flight, came much later.’
The study was published today in Trends in Ecology and Evolution: Benton, M.J., Dhouailly, D., Jiang, B., McNamara, M., 2019. The Early Origin of Feathers. Trends in Ecology and Evolution, in press. DOI: 10.1016/j.tree.2019.04.018.
See below for news items on the study:
This award is open to any laboratory or research group established within the last 3 years working in industry, at third level institutes, in the public service or at research institutions.
Well done to all!
The School of BEES is hosting a free half-day workshop on careers in geoscience targeted at second-level students from TY to 6th year in UCC on Saturday 23rd February – please see brochure below (or download here).
Schools / Guidance Councellors: feel free to bring this event to the attention of students in your careers guidance classes, and also to the science and geography classes in your school.
Please get in touch if you have any questions via return email to: firstname.lastname@example.org.
Scientists from University College Cork have discovered that pterosaurs had four kinds of feathers, shifting the origin of feathers back by 70 million years.
The new study, led by researchers from Nanjing University and UCC’s Dr Maria McNamara, shows that pterosaurs, which were flying reptiles that lived side by side with dinosaurs from 230 to 66 million years ago, had at least four types of feathers – simple filaments (‘hairs’), bundles of filaments, filaments with a tuft halfway down, and down feathers.
It had long been known that pterosaurs had a furry covering, but these ‘pycnofibres’ were thought to be fundamentally different to feathers of dinosaurs and birds. In fact, the new study shows that the pycnofibres are indeed feathers, and are similar to the feathers of dinosaurs, including the ancestors of birds.
Dr McNamara said “Some critics have suggested that there is only one simple hair-like type of pycnofibre, but our studies show different structures that we also see in dinosaurs – real feathers. We focused on areas where the feathers did not overlap and where we could see their structure more clearly. They even show fine details of pigment granules, which may have given the fluffy feathers a ginger colour.”
The hunt for feathers in fossils is heating up and deciphering their functions in such early animals forms a critical part of the puzzle. It could rewrite our understanding of a major revolution in life on Earth during the Triassic, and our understanding of the genomic regulation of feathers, scales, and hairs in the skin.
Zixiao Yang and Baoyu Jiang, of Nanjing University in China, studied the rocks from the Daohugou fossil localities and the pterosaurs. Mr Yang said “I was able to explore every corner of the specimens using high-powered microscopes, and we found many examples of all four feathers.”
UCD’s Prof. Patrick Orr and Prof. Mike Benton from the University of Bristol were also involved in the study. “We ran some evolutionary analyses, and they showed clearly that the pterosaur pycnofibres are feathers, just like those seen in modern birds and across various dinosaur groups,’ said Prof. Benton. “Because the structures in the pterosaurs have the same anatomy as the feathers of birds and dinosaurs, they must share an evolutionary origin about 250 million years ago, long before the origin of birds.”
Birds have two types of advanced feathers used in flight and for body smoothing, the contour feathers with a hollow quill and barbs down both sides. These are found only in birds and the theropod dinosaurs close to bird origins. However, the other feather types of modern birds include monofilaments and down feathers, and these are seen much more widely across dinosaurs and pterosaurs.
Dr McNamara said “This discovery has amazing implications for our understanding of the origin of feathers, but also for a major time of revolution of life on land. When feathers arose, about 250 million years ago, life was recovering from the devastating end-Permian mass extinction.“ Independent evidence shows that land vertebrates, including the ancestors of mammals and dinosaurs, were beginning to walk upright, had acquired different degrees of warm-bloodedness, and were generally living life at a faster pace. The mammal ancestors by then had hair, so likely the pterosaurs, dinosaurs and relatives had also acquired feathers to help insulate them.”
The study is published today in Nature Ecology and Evolution: Yang, Z.X., Jiang, B.Y., McNamara, M.E., Kearns, S.L., Pittman, M., Kaye, T.G., Orr, P.J., Xu, X., Benton, M.J. 2018. Pterosaur integumentary structures with complex feather-like branching. Nature Ecology and Evolution. DOI: 10.1038/s41559-018-0728-7.
See below for some news items on the study:
https://www.irishexaminer.com/breakingnews/ireland/not-just-splitting-hairs-ucc-study-pushes-origin-of-feathers-back-70m-years-892423.html (this was also on page 5 of the physical newspaper!:)
PhD student Valentina Rossi and postdoc Dr Thomas Clements were both Highly Commended for their talks at the 62nd Annual Meeting of the Palaeontological Association in Bristol over the weekend, receiving two runners-up places for the President’s Prize. A great achievement – well done to both!
(L-R) Dr Luke McDonald, Valentina Rossi, Dr Chris Rogers and Dr Thomas Clements.