We rarely have time to write about every great science story that comes our way. So this year we’re once again publishing a special Twelve Days of Christmas series, highlighting a science story that cracked 2022 every day from December 25th to January 5th. is as rare as scientists believe.
Under special conditions, dinosaur fossils can include remarkably well-preserved hides—a phenomenon long thought to be rare. But the authors are one October paper Based on an analysis of a mummified duck-billed hadrosaur with well-preserved skin showing unusual scavenging signs in the form of bite marks, published in the journal PLoS ONE, these dinosaur “mummies” suggest that these dinosaur “mummies” may have been more common than previously believed. .
In this case, the term “mummy” refers to fossils with well-preserved skin and sometimes other soft tissues. As we have previously reported, most fossils are bones, shells, teeth, and other forms of “hard” tissue, but rare fossils are found that preserve soft tissues such as skin, muscles, organs, and sometimes even the eyeball. It can tell scientists a lot about aspects of the biology, ecology, and evolution of ancient organisms that skeletons alone can’t.
For example, last year created by researchers A highly detailed 3D model of a 365 million year old ammonite fossil. jurassic period era by combining advanced imaging techniques, detection of internal muscles which has never been observed before. Another group of British researchers conducted experiments This involved watching the decay of dead sea bass carcasses to learn more about how (and why) the soft tissues of internal organs can be selectively preserved in the fossil record.
In the case of dinosaur mummies, there is ongoing debate over what appears to be a fundamental contradiction. The dino mummies discovered so far show signs of two different mummification processes. One is rapid burial, in which the body is quickly covered, which significantly slows advanced decomposition and protects the remains from debris. Another common way is desiccation, which requires the body to be exposed to the landscape for some time before burial.
The specimen in question is a partial skeleton EdmontosaurusA duck-billed hadrosaur discovered in the Hell Creek Formation of southwestern North Dakota and now part of the North Dakota State Fossil Collection. Nicknamed “Dakota,” this mummified dinosaur showed evidence of both rapid burial and desiccation. The remains have been studied since 2008 with various tools and techniques. The authors of the PLoS ONE paper also performed CT scans of the mummy, along with grain-size analysis of the sediments surrounding the fossil.
There were numerous cuts and holes on the forelegs and tail, as well as arc-shaped holes and scratches on the arm, hand bones and skin that resembled the shape of alligator teeth. The tail also had longer V-shaped slits that could have been made by a larger carnivore, such as a juvenile. tyrannosaurus rex.
Becky Barnes/PloS ONE
The authors conclude that there is more than one way dinosaurs were mummified, which resolves the debate in a way that “does not require an improbable convergence of events.” In short, dinosaur remains may be mummified more often than previously believed.
In Dakota’s case, the deflated appearance of skin over underlying bones has been seen in other dino mummies and is well documented in modern forensic research. The authors believe Dakota was “mummified” through a process called “desiccation and deflation.” In this process, animal carcasses are emptied, with scavengers and decomposers targeting the internal tissues, leaving the skin and bones behind. By David Bressan at Forbesthis is what happened to Dakota:
After the animal died, its body was probably scavenged by a pack of crocodiles, which opened the carcass in its belly and was colonized by flies and insects, removing the bones and skin from the rotting flesh. Such incomplete cleansing would expose the interior of the skin tissue, after which the outer layers would slowly dry out. The underlying bones would prevent the hollow body from shrinking too much while preserving the fine details of the scaly skin. Eventually, the now mummified remains were buried under mud, perhaps as the circulating fluids of the flash flood precipitated the minerals, replaced the remaining soft tissues, and preserved the rock cast.
“Dakota has taught us that not only can intact soft tissues, such as skin, be preserved in partially exhumed corpses, but these soft tissues can provide a unique source of information about other animals that interacted with the corpse after death.” said co-author Clint Boydpaleontologist at the North Dakota Geological Survey.
DOI: PLoS ONE, 2022. 10.1371/journal.pone.0275240 (About DOI).
