We rarely have time to write about every great science story that comes our way. So this year, we’re releasing a special Twelve Days of Christmas post series every day from December 25th to January 5th, highlighting an overlooked science story in 2022. Today: Why might there not be dinosaur “mummies”? It may be as rare as scientists believe.
Under certain circumstances, dinosaur fossils may contain exceptionally well-preserved skin – an event long considered rare. But the authors are sowing paper An article published in the journal PLoS ONE suggested that these dinosaur “mummies” may have been more common than previously believed, based on an analysis of a mummified duck-billed hadrosaur with well-preserved skin that showed signs of unusual hunting in the form of bite marks. .
In this case, the term “mummy” refers to fossils with well-preserved skin and sometimes other soft tissues. as we have previously reportedMost fossils are bones, shells, teeth, and other forms of “hard” tissue, but rare fossils are sometimes discovered that preserve soft tissues such as skin, muscles, organs, and even the occasional eyeball. This can tell scientists a lot about the biology, ecology, and evolution of such ancient organisms that skeletons alone cannot convey.
For example, last year, researchers have created A highly detailed 3D model of a 365-million-year-old ammonite fossil Jura term combining advanced imaging techniques, reveal inner muscles which has never been observed before. Another team of British researchers experiments carried out It involved monitoring the decay of dead perch carcasses to learn more about how (and why) the soft tissues of internal organs can be selectively preserved in the fossil record.
There is an ongoing debate over what seems to be a central contradiction when it comes to dinosaur mummies. The dino mummies discovered so far show signs of two different mummification processes. The first is rapid burial, in which the body is rapidly covered and enhanced decomposition is greatly slowed and the remains are protected from collection. The other common route is drying, which requires the body to be exposed to the landscape for some time before it is buried.
The example in question is a partial skeleton. edmontosaurs, a duck-billed hadrosaur discovered in the Hell Creek Formation in southwestern North Dakota and is now part of the North Dakota State Fossil Collection. Dubbed the “Dakota,” this mummified dinosaur showed evidence of both rapid burial and desiccation. The remains have been studied with a variety of tools and techniques since 2008. Along with CT scans of the mummy, the authors of the PLoS ONE paper also performed an analysis of the grain size of the sediments in the surrounding area where the fossil was found.
There was evidence of multiple slits and punctures on the forelimbs and tail, as well as arc-shaped holes and abrasions on the arm, hand bones, and skin that closely resembled the shape of crocodile teeth. There were also longer V-shaped slits in the tail that might have been made by a larger carnivorous predator such as a juvenile. Tcrannosaur rex.
The authors concluded that there was probably more than one path to dinosaur mummification and resolved the debate in a way that “does not require the extraordinarily unlikely convergence of events.” In short, dinosaur remains may have been mummified more often than previously believed.
In the case of the Dakota, the dull appearance of the skin over the underlying bones was seen in other dino mummies and is well documented in modern forensic studies. The authors believe the Dakota was “mummified” through a process called “drying and quenching,” which involves incomplete cleansing, in which animal carcasses are emptied, targeting internal tissues, leaving skin and bone behind. Per David Bressan at ForbesThis is probably what happened to Dakota:
After the animal died, its body was probably scavenged by a group of crocodiles, its carcass ripped open from its belly and colonized by flies and insects that scavenged bones and skin from rotting flesh. Such incomplete sweep exposed the dermal tissue interiors and then the outer layers gradually dried out. The underlying bones would preserve the finer details of the scaly skin, preventing the hollow body from contracting too much. Finally, the now mummified remains were buried under mud, perhaps due to a flash flood, and circulating fluids deposited minerals, replacing the remaining soft tissue and preserving the cast in the rock.
“The Dakota not only taught us that durable soft tissues such as skin can be preserved in partially cleaned carcasses, but these soft tissues can also provide a unique source of information about other animals that interact with a carcass after death.” co-author Clint Boyd saidand a paleontologist from the North Dakota Geological Survey.
DOI: PLoS ONE, 2022. 10.1371/journal.pone.0275240 (About DOIs).
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