Here we use taphonomic experiments to show that the chemistry of melanosomes from different tissues converges during maturation – in particular, Cu signals become more homogeneous. Fossils with uniform or widespread elevation in Cu were probably diagenetically altered and don’t preserve original melanosome chemistries. This is potentially a new way of testing whether fossils are relatively unaltered in terms of their chemistry.
The study was published today in the journal Geology.
Rossi, V., Webb, S.M., McNamara, M., 2021. Maturation experiments reveal bias in the chemistry of fossil melanosomes. Geology, 49. DOI: https://doi.org/10.1130/G48696.1.
Maria was awarded almost €300K in funding from SFI as part of their Discover scheme to fund public engagement initiatives.
Her funded project, “Ireland’s Secret Past: unlocking our Fossil Heritage” will expand the work from the pilot project of the same name which ran from Jan – Dec 2019.
This project will build on an extremely successful SFI-funded pilot project to exploit palaeontology, a critical gateway science, to enhance understanding and perceptions of STEM in Ireland. The project will reach out to thousands of Irish children and adults via hands-on, digital and interpersonal formats that encourage hypothesis-testing and active kinaesthetic learning. Bespoke resources tailored to Irish fossils will complement a novel national network of urban fossil trails. A ground-breaking interactive exhibit hosted at national and regional science fairs will showcase Irish fossils and incorporate cutting-edge technology previously inaccessible to the public. Workshops will be delivered to schoolchildren around the country via videolink and/or in person. Collaborations with artists will encourage the public to engage with fossils in new ways through workshops, creation of an exhibition and e-book and art competitions. Other national events include public lectures, a touring photography exhibition and a vote for Ireland’s favourite fossil, promoting palaeontology, and STEM more broadly, as topics of national importance. The project will reach out to women and girls, and residents of disadvantaged communities, direct provision centres, offshore islands, and counties with little STEM intervention. Impact will be measured using qualitative and quantitative means, integrated into key activities at predetermined stages of the project, including statistics on website- and social media interaction, interviews, workshops, surveys, poster exercises and quizzes. By raising the profile of palaeontology, this project will inspire curiosity in our ancient past at a national scale, ultimately reforming national science curricula and stimulating pursuit of STEM careers.
As of 2021 we are expanding the programme to the whole country and with exciting new activities! We are looking for project partners so please get in touch by contacting Maria (firstname.lastname@example.org) or Naomi (email@example.com). For more information click here or check the project’s dedicated website here.
Author Helen Gordon interviewed Maria about her work on palaeo colour and it is now part of the new book “Notes From Deep Time”, published today. The book delves into Earth’s life-story, from London’s fossils and ancient rocks that are billions of years old, to hidden volcanoes and plate tectonics.
Read more about the book here: https://profilebooks.com/work/notes-from-deep-time/.
It can be purchased here: https://www.amazon.co.uk/dp/1788161637.
Fossil pigments shed new light on vertebrate evolution
UCC palaeontologists have discovered new evidence that the fate of vertebrate animals over the last 400 million years has been shaped by microscopic melanin pigments.
This new twist in the story of animal evolution is based on cutting-edge analyses of melanin granules – melanosomes – in many different fossil and modern vertebrates, including fish, amphibians, reptiles, birds and mammals. Melanin and melanosomes have traditionally been linked to outermost body tissues such as skin, hair and feathers, with important roles in UV protection and stiffening of tissues. Analyses of where different animals store melanin in the body, however, show that different vertebrate groups concentrate melanin in different organs, revealing shifts in how animals have used melanin over the last 400 million years.
The study, published today in the journal Trends in Ecology and Evolution, was led by UCC palaeontologists Prof. Maria McNamara, Dr Chris Rogers, Dr Valentina Rossi and PhD student Tiffany Slater, with an international team of evolutionary biologists from Switzerland.
“Most studies of fossil melanin have focussed on melanin in fossil feathers and skin, and what colours ancient animals had,” said study leader Prof. McNamara. “By comparing melanin in different animals – how much melanin they have, where in the body it occurs, what melanin type and composition is present – and by studying fossils, we discovered new evidence for changes in the functions of melanin through deep time.”
The research shows that amphibians and reptiles concentrate melanin in internal organs, where it supports the immune system and stores metals. In birds and mammals, however, almost all melanin occurs in hair and feathers. This difference has an unexpected source – evolution of the immune system and of warm-blooded lifestyles.
“There are pros and cons to having melanin in the body,” said team member Dr Rossi. “Melanin is hugely beneficial, but it also generates free radicals, which are harmful. This creates a major problem for animals.”
During the evolution of hair and feathers, mammals and birds evolved more sophisticated immune systems than in amphibians and reptiles. This meant that large amounts of melanin were no longer necessary in internal organs. Melanin storage then shifted to hair and feathers, which are dead tissues, thereby removing harmful metals and free radicals from living body parts.
“Melanin is a two-sided coin,” said Prof. McNamara. “It’s useful, but toxic. Birds and mammals basically came up with an ingenious solution during the early Triassic – pump melanin into new, outer, dead skin tissues that were evolving at the time. This set the scene for the evolution of the incredible diversity of plumage and fur patterning which we see today.”
The study also shows that key genes can be mapped onto colour patterns in fossils, tracking the genetic evolution of melanin through time, and that animals preferentially use less toxic forms of melanin. “There’s still a lot about melanin genetics and physiology that we don’t understand,” said Dr Ducrest of Lausanne University. What’s clear, however, is that the fossil record is a valuable source of information that we can use going forwards.”
The study is published today in the journal Trends in Ecology and Evolution.
McNamara, M.E., Rossi, V., Slater, T.S., Rogers, C.S., Ducrest, A.-L., Dubey, S., Roulin, A., 2021. Decoding the Evolution of Melanin in Vertebrates. TREE, published online 3/2/2021. DOI: https://doi.org/10.1016/j.tree.2020.12.012.
Dr Maria McNamara, Dr Valentina Rossi and Tiffany Slater spoke (as Gaeilge!) about dinosaurs and their footprints on this evening’s episode of “Is Eolaí Mé” on TG4. Maria also explained a little bit more about dino colours and her favourite dinosaur! Click the link here or the image below (their feature starts at 14:40!) to watch.