There is no more than one way to mummify a dinosaur, the study found

We rarely have time to write about every cool science-y story that comes our way. So again this year we ran a special series of 12 days of Christmas news, highlighting one of the science stories that fell through the cracks in 2022, every day from January 25 through 5. Today: Why dinosaurs “mummy” could not be as rare as scientists believed.

Under certain conditions, dinosaur fossils can contain exceptionally well-preserved skin, something long considered rare. But the authors of a paper published in October in the journal PLoS UNO suggested that these “mummy” dinosaurs were more common than previously believed, based on an analysis of a mummified hadrosaur duck with well-preserved skin that showed unusual telltale signs. in the form of bite-sized scavenging on the notes.

In this case, the term mummy refers to a fossil that has well-preserved skin and sometimes other soft tissue. Most fossils, as we said before, are bones, shells, teeth, and other forms of “hard” tissue, but rare fossils are sometimes found that preserve soft tissues such as skin, muscles, organs, or sometimes even eyes. This can tell scientists a lot about aspects of the biology, ecology, and evolution of ancient organisms that skeletons alone cannot convey.

For example, last year, researchers created a highly accurate 3D model of a Jurassic fossil fossil from the Jurassic period by combining advanced imaging techniques to reveal internal muscles that had never been observed before. Another team of British researchers conducted experiments involving the viewing of dead sea bass carcasses to learn more about how (and why) the soft tissues of internal organs can be selectively preserved in fossils.

The ongoing debate over what appears to be a central contradiction in dinosaur mummies. The dino mummies found so far show signs of two different mummification processes. One is quick burial, in which the body is quickly covered and further decay is substantially slowed and the remains are protected from excavations. Another common method is desiccation, which requires the body to remain exposed for a period of time before burial.

The specimen in question is a partial skeleton EdmontosaurusThe hadrosaur was found in the Hell Creek Formation of southern North Dakota and is now part of the North Dakota State Fossil Collection. Dubbed “Dakota,” this mummified dinosaur shows evidence of both burial and rapid desiccation. The remains have been investigated using a variety of tools and techniques since 2008. The authors of the PLoS ONE paper performed CT scans of the mummy, along with a grain-size analysis of the surrounding sediment in which the fossils were found.

There was evidence of multiple sarcophagi and punctures in the front and tail, as well as holes and abrasions in the arm, hand bones, and skin in the form of a bow, much like the shape of crocodile teeth. There were also longer V-shaped tails on the tails that could have been made by a larger carnivorous predator, such as juveniles. Tyrannosaurus King.

The authors conclude that there is more than one path to dinosaur mummification, framing the debate in a way that “seems unlikely to require a confluence of events.” In short, dinosaur remains can be mummified more often than previously believed.

In Dakota, the type of skin underneath the bones has been seen in other dino mummies and has also been documented in recent forensic studies. The Dakota authors believe it was “mummified” through a process called “desiccation and deflation,” which is incomplete scavenging in which the animal’s carcass is emptied so that scavengers and decomposers attack the internal tissues, leaving the skin and bones behind. By David Bressan at Forbes it is likely that this happened to Dakota;

When the animal was dead, its body was surrounded by a pack of crocodiles, opening the corpse to the belly, carried off by flies and beetles, cleaning the bones and skin from the rotting flesh. Such an incomplete excavation would have exposed the inner dermal tissue, after which the outer layers gradually dried up. The underlying bones would prevent the empty vessel from shrinking too much, and would keep the scaly skin thinner. Finally, the now mummified remains were buried under the mud, possibly by a flash flood and the circulation of the deposited mineral waters, reposing the remaining soft tissues and preserving them projected into the rock.

“Not only has the Dakota taught us that durable soft tissues such as skin can be preserved attached to corpses, but these soft tissues can also provide a unique source of information about other animals that interact with corpses after death,” said Clint Boyd, a paleontologist at the North Dakota Geological Survey.

DOI: PLoS PRIMA, 2022. 10.1371/journal.pone.0275240 (About DOIs).