A new analysis of a natural ‘mummy’ of the hadrosaurian dinosaur Edmontosaurus from the Hell Creek Formation of southwestern North Dakota — which preserves large patches of desiccated and seemingly deflated skin on the limbs and tail — reveals an alternate fossilization pathway for dinosaur soft tissues (e.g., skin and nails).
Evidence of desiccation in Edmontosaurus. Image credit: Drumheller et al., doi: 10.1371/journal.pone.0275240.
The term ‘mummy’ has become an informal catch-all for fossils exhibiting extremely well-preserved skin and sometimes other soft tissues.
It is commonly suggested that such fossils only form under exceptional circumstances and that a carcass must be shielded from scavenging and decomposition by rapid burial and/or desiccation in order for skin to become fossilized.
In a new study, Dr. Stephanie Drumheller from the University of Tennessee-Knoxville and his colleagues combined fossil evidence with observations on modern animal carcasses to propose a new explanation for how such dinosaur ‘mummies’ might form.
They examined a ‘mummy’ of the hadrosaurian dinosaur Edmontosaurus from the Hell Creek Formation on North Dakota.
They identified bite marks from carnivores upon the dinosaur’s skin.
These are the first examples of unhealed carnivore damage on fossil dinosaur skin, and furthermore, this is evidence that the dinosaur carcass was not protected from scavengers, yet it became a mummy nonetheless.
Modern animal carcasses are known to be often emptied out as scavengers and decomposers target internal tissues, leaving behind skin and bone.
“Damage to this dinosaur’s skin from incomplete scavenging would have exposed its insides and allowed a similar process to occur, after which the skin and bones became slowly desiccated and buried,” the researchers said.
“This process, which we call desiccation and deflation, is common with modern carcasses and explains how dinosaur mummies might form under relatively ordinary circumstances.”
“There are likely numerous pathways by which a dinosaur mummy might develop.”
“Understanding these mechanisms will guide how paleontologists collect and interpret such rare and informative fossils.”
The research is described in a paper published online in the journal PLoS ONE.
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S.K. Drumheller et al. 2022. Biostratinomic alterations of an Edmontosaurus ‘mummy’ reveal a pathway for soft tissue preservation without invoking ‘exceptional conditions.’ PLoS ONE 17 (10): e0275240; doi: 10.1371/journal.pone.0275240
Source link: https://www.sci.news/paleontology/dinosaur-soft-tissue-preservation-11285.html
