Além dos ossos Parte 2 Preservação excepcional em fósseis de dinossauros múmias de dinossauro

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Além dos ossos, Parte 2: Preservação excepcional em fósseis
de dinossauros – “múmias” de dinossauro
Tanya Samman e Alina C. Editores de Fisher, Ciências Ambientais e da Terra
Na Parte 1 desta série de duas partes, discutimos descobertas que nos deram novos insights fascinantes
sobre o funcionamento interno dos dinossauros e instantâneos da aparência dos dinossauros, mas as
“múmias” dos dinossauros são ainda mais emocionantes e reveladoras.
“Mummies”
O que é exatamente uma “múmia” de dinossauros? Quando a maioria das pessoas pensa em fósseis de
dinossauros, elas geralmente pensam em ossos. “Mummies”, no entanto, são restos de dinossauros que
preservam o exterior do animal (por exemplo, pele, escamas, armaduras) sobre grandes áreas do corpo,
cobrindo os ossos e lembrando a carcaça de um animal moderno recentemente morto, apenas fossilizado.
Vamos apresentá-lo a três “mummies” de dinossauros, incluindo um espécime tridimensional espetacular de
Alberta.
DakotaTrata-
Um hadrossauro extremamente bem preservado (cf. Edmontosaurus sp.) foi encontrado na Formação Helé
Creek do Cretáceo Superior de Dakota do Norte (cerca de 65 a 70 milhões de anos de idade). Apelidado de
Dakota, este espécime contém pele mineralizada, que tem estruturas celulares microscópicas entre cinco e 30
mícrons de largura. Curiosamente, as escamas na pele têm um padrão listrado, que nos répteis modernos
muitas vezes significa uma mudança de cor.
https://blog.scienceborealis.ca/tanya-samman-environmental-earth-sciences-editor/
https://blog.scienceborealis.ca/alina-fisher-environmental-earth-sciences-editor/
https://blog.scienceborealis.ca/alina-fisher-environmental-earth-sciences-editor/
https://wp.me/p8dH8m-1yf
https://royalsocietypublishing.org/doi/full/10.1098/rspb.2009.0812
https://royalsocietypublishing.org/doi/full/10.1098/rspb.2009.0812
https://www.theguardian.com/science/2007/dec/03/dinosaurs.fossils
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De acordo com o Dr. Phil Manning, a presença de pele permite-lhe estimar o volume de músculo abaixo,
permitindo-lhe calcular a energia muscular, velocidade e força de um dinossauro. Uma das coisas mais legais
sobre este espécime é que ele preserva o que parece ser uma estrutura semelhante a um casco no pé da
frente direita. Os pés de Hadrosaur são geralmente reconstruídos com dedos individuais.
Leonardo (s)
Dakota não é o único hadrossauro bem preservado – há outro, um Brachylophosaurus chamado Leonardo da
Formação do Rio Judith do Cretáceo Superior de Montana (cerca de 75 a 78 milhões de anos).
Os pesquisadores usaram radiografia (popularmente, mas incorretamente conhecida como imagem de raios-
X) para espiar o fóssil. Eles encontraram evidências de uma cultura semelhante a um pássaro no pescoço e
fizeram imagens de seu coração e fígado (que são, reconhecidamente, controversas). Análises físicas e
químicas revelaram o conteúdo do seu sistema digestivo, incluindo material de samambaias, coníferas e
magnólias.
Borealopelta markmitchelliTradução
Um dos “mummies” de dinossauros mais emocionantes vem daqui, no Canadá. Este espécime de um
nodossauro de 110 milhões de anos, um tipo de anquilossauro (dinossauro blindado), foi encontrado por acaso
na Formação Cretáceo Inferior em Suncor Millennium Mine, Fort McMurray, Alberta, pela escavadora Shawn
Funk.
Fotografia de visão lateral do holótipo de Borealopelta markmitchelli, Museu Real Tyrrell de Paleontologia (TMP)
2011.033.0001. Parte da Figura 1, Brown et al. 2017 CC BY-NC-ND 4.0
“The specimen was a huge surprise,” says Royal Tyrrell Museum of Palaeontology Curator of Dinosaurs Dr.
Don Henderson. “We knew from the first day we saw some isolated pieces on the floor of the Suncor firehall,
that we had something exceptional. There had been a gentle trickle of nearly complete plesiosaurs and
https://www.research.manchester.ac.uk/portal/phil.manning.html
https://www.scientificamerican.com/article/scientists-flesh-out-foss/
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ichthyosaurs since the 1990s from the tar sands, but to find a terrestrial dinosaur in the same [marine] rocks
was completely unexpected.”
Henderson says getting the specimen out of the ground took a variety of equipment and the work of a large
crew over almost two weeks.
“Before we could employ any heavy equipment to get the specimen out, we spent two days combing through
the rubble to collect all the pieces shattered and scattered by the initial bucket hit,” he says. “Excavation then
started with big excavators and over the next two weeks the machines and tools got smaller and smaller,
ending with hammers and chisels. Large numbers of Suncor staff went out of their way to help us over the 17
days we were on site. Many university students on internships with Suncor had a nice day or two away from the
office by helping us making plaster jackets during the final stages of the removal.”
Borealopelta markmitchelli, which translates as “Mark Mitchell’s northern shield”, was named in honour of the
Royal Tyrrell Museum of Technology technician who spent about 7,000 hours – almost six years! –
painstakingly removing the rock encasing the specimen.
“Preparing the nodosaur was both exciting and challenging,” Mitchell describes his experience preparing the
specimen. “I knew the specimen was exceptionally well-preserved based on the cross sections and counter
pieces that were brought to the museum. I initially used large airscribes and zip guns to remove excess rock. I
then switched to smaller airscribes and a pin vise to expose the bone/skin surface a few millimeters at a time.
The combination of the hard rock and the soft powdery nature of the fossil bone, especially the osteoderms,
made the preparation quite difficult. As the first completed pieces were placed together, the nodosaur began to
take shape. This bolstered my enthusiasm to get started on the next piece of the specimen.”
When asked how he felt about the dinosaur’s name, he said, “Having the nodosaur named after me is a great
honor”.
https://www.britannica.com/animal/ichthyosaur
https://nationalpost.com/news/local-news/new-dinosaur-species-named-after-alberta-researcher-who-worked-on-specimen-for-six-years/wcm/0462bad2-748e-48cd-8be6-4534a0ac9301
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Face-on view photograph of the holotype of Borealopelta markmitchelli, Royal Tyrrell Museum of
Palaeontology (TMP) 2011.033.0001. Part of Figure 1, Brown et al. 2017 CC BY-NC-ND 4.0
What is unique about this specimen is that it is three-dimensional and incredibly-life-like, unlike Dakota and
Leonardo, which are flattened and withered looking. It was revealed to have abundant in situ (i.e., in life
position) osteoderms (bones in the skin layer) with keratinous sheaths and scales preserved. In addition, its
reddish-brown color and crypsis countershading that allowed it to avoid observation or detection by other
animals indicates the strong predation pressure on this herbivorous dinosaur.
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Banner image: People often think of dinosaur fossils as skeletons in rock or some kind of matrix and
surrounded by plaster, like this Ornithomimus edmontonicus (Royal Tyrrell Museum of Palaeontology(TMP)
95.110.01). This specimen preserves a beak at the tips of its jaws, as described in Part 1 of this series. Photo
by Tanya Samman
https://blog.scienceborealis.ca/wp-content/uploads/sites/2/2020/02/Borealopelta-face-on-RTMP.jpg
https://www.cell.com/current-biology/fulltext/S0960-9822(17)30808-4
https://en.wikipedia.org/wiki/Osteoderm
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https://en.wikipedia.org/wiki/Crypsis
https://wp.me/p8dH8m-1yf