Dinosaur mummies may be more common than thought

Popularly known as “dinosaur mummies”, the fossils that keep the skin and other soft tissues still preserved are considered rare by the scientific community. New work, however, indicates that these specimens may be more common than previously thought.

A team of paleontologists from the United States challenged the main concept that would guarantee the exceptionality of “mummies”: that they only formed under very specific conditions, when the bodies of dead animals were quickly buried and protected from contact with other animals.

From the detailed analysis of one of these fossils, scientists have identified that there is an alternative — and much easier — route to preserving fossilized skin.

The researchers investigated the “mummy” of an Edmontosaurus (a genus that could reach nine tons), named Dakota in honor of the region where it was found, the state of North Dakota, in the midwest of the USA.

Teeth marks were identified on the skin of the dinosaur’s tail and paw. There were no signs of scarring on the tissue, which indicates that the bites were likely made by scavengers.

Due to the characteristics of dental marks, it is believed that they were caused by at least two different animals, one of them being a type of prehistoric crocodile.

The fact that the dinosaur’s meat served as food for scavengers indicates that the material was exposed to the environment for some time, and therefore there was no quick burial. Contrary to leading theories of dinosaur mummies forming, part of the Dakota’s skin was fossilized even with prolonged exposure to the environment.

“Given the previous explanations for the preservation of dinosaur ‘mummies’, this fossil should never have formed”, evidences the article, led by Stephanie K. Drumheller, from the University of Tennessee.
From a sequence of analyzes on the Dakota fossil, scientists came up with another hypothesis for conservation.

According to the work, the bite holes in the dinosaur’s carcass “provided an escape route for the gases, fluids and microbes associated with decomposition.” This eventually allowed more durable soft tissues to resist for the weeks or months needed to reach the extreme dry state that preceded the burial and fossilization of the material.

The process described by the researchers is often seen in modern animals as well, whose carcass is “emptied” as scavengers and decomposing organisms attack the internal tissues, leaving only skin and bones.

These observations helped to reinforce the hypothesis presented in the article, published last Wednesday (12) in the scientific journal PLoS One.

In the assessment of paleontologists, there are probably several paths for the formation of “dinosaur mummies”, and a better understanding of these mechanisms would help to broaden the interpretation of prehistoric life.

A professor at URCA (Universidade Regional do Cariri) and curator of the Museu do Cariri, in Ceará, paleontologist Renan Bantim considers that the process described by the Americans is truly innovative.

“This discovery brings up the possibility of reassessing the preservation of these and other organic structures, such as organs, muscle fibers and blood vessels, allowing even new discoveries to be revealed in known fossils”, he says.

According to Bantim, the work could also have an impact on the study of abundant fossils in the Araripe Basin region, in northeastern Brazil, where, since 1996, it is known that there are preserved organic tissues.

“Several analyzes in search of fossilized soft parts have been carried out on fossils of pterosaurs, crocodiles, turtles, amphibians and fish from the Romualdo Formation, the most recent finding being associated with the preservation of the fossilized heart of the fish. rhacolepis buccalis“, enumerates.

“Therefore, after the discovery of the preservation of the skin of the Edmontosaurus dinosaur, it is necessary to pay attention to the occurrence of the same type of fossilization in Brazil, especially in those found in the Araripe basin”, he adds.

The Brazilian specialist also draws attention to the uniqueness of the identified brands. “For the first time, in soft tissue studies of fossilized animals, the presence of scavenger marks on the skin of a dinosaur is evidenced due to the carcass feeding action by crocodiles and insects.”