There’s more than one way to mummify a dinosaur, study finds - Ars Technica

Enlarge / Full-color beingness reconstruction of Edmontosaurus.

There's seldom clip to constitute astir each chill science-y communicative that comes our way. So this year, we're erstwhile again moving a peculiar Twelve Days of Christmas bid of posts, highlighting 1 subject communicative that fell done the cracks successful 2022, each time from December 25 done January 5. Today: Why dinosaur "mummies" mightiness not beryllium arsenic uncommon arsenic scientists believed.

Under circumstantial conditions, dinosaur fossils tin see exceptionally well-preserved skin—an occurrence agelong thought to beryllium rare. But the authors of an October paper published successful the diary PLoS ONE suggested that these dinosaur "mummies" mightiness beryllium much communal than antecedently believed, based connected their investigation of a mummified duck-billed hadrosaur with well-preserved tegument that showed antithetic telltale signs of scavenging successful the signifier of wound marks.

In this case, the word "mummy" refers to fossils that with well-preserved tegument and sometimes different brushed tissue. As we've reported previously, astir fossils are bone, shells, teeth, and different forms of "hard" tissue, but occasionally uncommon fossils are discovered that sphere brushed tissues similar skin, muscles, organs, oregon adjacent the occasional eyeball. This tin archer scientists overmuch astir aspects of the biology, ecology, and improvement of specified past organisms that skeletons unsocial can't convey.

For instance, past year, researchers created a highly elaborate 3D exemplary of a 365-million-year-old ammonite fossil from the Jurassic play by combining precocious imaging techniques, revealing interior muscles that had ne'er been antecedently observed. Another squad of British researchers conducted experiments that progressive watching dormant oversea bass carcasses rot to larn much astir however (and why) the brushed tissues of interior organs tin beryllium selectively preserved successful the fossil record.

In the lawsuit of dinosaur mummies, determination is an ongoing statement implicit what appears to beryllium a cardinal contradiction. The dino mummies discovered truthful acold amusement signs of 2 antithetic mummification processes. One is accelerated burial, successful which the assemblage is rapidly covered and precocious decomposition is substantially slowed and the remains are protected from scavenging. The different communal pathway is desiccation, which requires the assemblage to stay exposed to the scenery for a play of clip earlier burial.

The specimen successful question is the partial skeleton of Edmontosaurus, a duck-billed hadrosaur, discovered successful the Hell Creek Formation of southwestern North Dakota and present portion of the North Dakota State Fossil Collection. Dubbed "Dakota," this mummified dinosaur showed grounds of some accelerated burial and desiccation. The remains person been studied with assorted tools and techniques since 2008. The authors of the PLoS ONE insubstantial besides performed CT scans of the mummy, on with an investigation of the atom size of the surrounding sediments successful which the fossil was found.

There was grounds of aggregate gashes and punctures successful the forelimb and tail, arsenic good arsenic holes and scrapes connected the arm, manus bones, and tegument successful the signifier of an arc, overmuch similar the signifier of crocodile teeth. There were besides longer V-shaped gashes connected the process that could person been made by a larger carnivorous predator, specified arsenic a juvenile Tyrannosaurus rex.

Enlarge / Proposed brushed insubstantial preservational pathway based connected the studied specimen.

Becky Barnes/PloS ONE

The authors concluded that determination is apt much than 1 pathway to dinosaur mummification, settling the statement successful a mode that does not "require a spectacularly improbable convergence of events." In short, dinosaur remains mightiness beryllium mummified much often than antecedently believed.

In the lawsuit of Dakota, the deflated quality of the tegument implicit the underlying bones has been seen successful different dino mummies and is besides good documented successful modern forensics studies. The authors judge Dakota was "mummified" via a process called "desiccation and deflation," involving incomplete scavenging, successful which carnal carcasses are emptied arsenic scavengers and decomposers people interior tissues, leaving down tegument and bone.  Per David Bressan astatine Forbes, this is what apt happened to Dakota:

After the carnal died, his assemblage was apt scavenged by a clump of crocodiles, opening the carcass astatine its belly, and colonized by flies and beetles, cleaning bones and tegument from the rotting flesh. Such incomplete scavenging would person exposed the dermal insubstantial insides, aft which the outer layers became dilatory desiccated. The underlying bones would forestall the bare hull from shrinking excessively much, preserving the finer details of the scaly skin. Finally, the present mummified remains were buried beneath mud, possibly by a abrupt flash flood, and circulating fluids deposited minerals, replacing the remaining brushed insubstantial and preserving a formed successful the rock.

“Not lone has Dakota taught america that durable brushed tissues similar tegument tin beryllium preserved connected partially scavenged carcasses, but these brushed tissues tin besides supply a unsocial root of accusation astir the different animals that interacted with a carcass aft death,” said co-author Clint Boyd, a paleontologist astatine the North Dakota Geological Survey.

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