Slater, T., Ashbrook, K., Kriwet, J., 2020. Evolutionary relationships among bullhead sharks (Chondrichthyes, Heterodontiformes). Papers in Palaeontology, available via Early View: https://doi.org/10.1002/spp2.1299.
Review of the PalAss 2019 Annual Meeting including a special mention for Maria’s Annual Address:
UCC palaeontologists have discovered new evidence on what type of animal is the bizarre 300 million year old fossil known as the “Tully Monster”. The new findings show that the Tully Monster may not be a backboned animal as previously thought.
This new twist in the tale of the Tully Monster is based on cutting-edge analyses of melanin granules – melanosomes – in Tully’s weird stalked eyes. Chemical tests show that Tully’s eye melanosomes resemble those in animals without backbones.
The study, published today in the journal Proceedings of the Royal Society B: Biological Sciences, was led by UCC’s Drs Chris Rogers and Maria McNamara with an international team of scientists from the UK, USA and Japan.
The team used cutting-edge techniques to analyse the structure and chemistry of the eyes of the Tully Monster fossil, along with various other fossils and modern animals.
The eyes of Tully contain layers of melanosomes, a feature thought to exist only in the eyes of animals with backbones. Surprisingly, however, the new study shows that these layers are also found in the eyes of animals without backbones, such as octopus and squid. ‘I was amazed’ said Dr Rogers. ‘for decades scientists have failed to identify the pigments in the eyes of animals like the octopus, but our chemical tests show it’s definitely melanin.’ Powerful X-ray analyses show that the eye melanosomes of animals with and without backbones contain different metals. Controversially, the metals in the Tully Monster’s eyes are like those of animals without backbones. ‘This means that invertebrates are still contenders for the Tully animal,’ says senior author Dr McNamara. ‘The riddle of what kind of fossil creature this is continues, but future X-ray work will probably play an important part in figuring out the identity of Tully Monster and other enigmatic fossils.’
Rogers, C.S., Astrop, T.I.A., McNamara, M.E., Webb, S., Ito, S., Wakamatsu, K. Synchrotron-X-ray absorption spectroscopy of melanosomes in vertebrates and cephalopods: implications for the affinity of Tullimonstrum. Proceedings B, 286, 20191649. DOI: https://doi.org/10.1098/rspb.2019.1649.
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Congratulations to UCC student Tiffany for her paper published last week, and adding fuel to the fossil feather preservation debate!
Slater, T.S., McNamara, M.E., Orr, P.J., Foley, T.B., Ito, S., Wakamatsu, K., 2019. Taphonomic experiments resolve controls on the preservation of melanosomes and keratinous tissues in feathers. Palaeontology, xx. DOI: 10.1111/pala.12445.
It is open-access and can be viewed at the following link:
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.
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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.
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