Dinosaur ‘Mummies’ Might Not Be As Unusual As We Think
Life reconstruction of Edmontosaurus.
The time period “mummy” is usually used to explain dinosaur fossils with fossilized pores and skin. It’s generally prompt that such fossils solely kind underneath distinctive circumstances and {that a} carcass have to be shielded from scavenging and decomposition by fast burial and/or desiccation to ensure that pores and skin to turn into fossilized.
In a brand new research, researchers of the College of Tennessee–Knoxville mixed fossil proof with observations on fashionable animal carcasses to suggest a brand new rationalization for a way such “mummies” would possibly kind.
The researchers examined an Edmontosaurus named Dakota – after the positioning in North Dakota the place the fossil was discovered – which preserves massive patches of desiccated and seemingly deflated pores and skin on the limbs and tail. They recognized chunk marks upon the dinosaur’s pores and skin. These are the primary examples of unhealed carnivore harm on fossil dinosaur pores and skin, and moreover, that is proof that the dinosaur carcass was not shielded from scavengers, but it grew to become a mummy nonetheless.
Dakota’s leg exhibiting finer particulars, like scaly pores and skin and hoofed digits.
Trendy scavengers and decomposers goal the gentle inside tissues, biting or ripping aside an animal carcasses. This creates openings within the physique wall by means of which fluids and gasses can escape. Additionally invertebrates and microbes use these openings to entry the interior tissues, at first rushing up decomposition.
However the elimination of inside gentle tissues and drainage of fluids and gasses related to decomposition permits the outer gentle tissue, like pores and skin and different dermal tissues, to rapidly desiccate. This course of facilitates longer-term persistence of the pores and skin and different resistant gentle tissues till eventual burial and fossilization.
Primarily based on the accessible geological proof, the authors suggest Dakota’s fossilization occurred as follows:
After the animal died, his physique was doubtless scavenged by a bunch of crocodiles, opening the carcass at its stomach, and colonized by flies and beetles, cleansing bones and pores and skin from the rotting flesh. Such incomplete scavenging would have uncovered the dermal tissue insides, after which the outer layers grew to become slowly desiccated. The underlying bones would stop the empty hull from shrinking an excessive amount of, preserving the finer particulars of the scaly pores and skin. Lastly, the now mummified stays have been buried beneath mud, possibly by a sudden flash flood, and circulating fluids deposited minerals, changing the remaining gentle tissue and preserving a solid within the rock.
Proposed gentle tissue preservational pathway based mostly on the studied specimen.
This course of, which the authors name “desiccation and deflation,” is widespread with fashionable carcasses and explains how dinosaur mummies would possibly kind underneath comparatively bizarre circumstances. The authors stress that there are doubtless quite a few pathways by which a dinosaur mummy would possibly develop. Understanding these mechanisms will information how paleontologists gather and interpret such uncommon and informative fossils.
The paper “Biostratinomic alterations of an Edmontosaurus “mummy” reveal a pathway for gentle tissue preservation with out invoking “distinctive situations” is printed in PLoS One (2022). Materials offered by PLoS.
