The "mummies" dinosaur might not be so rare

Oct. 12 () – –

A process of desiccation and deflation explains why dinosaur ‘mummies’ aren’t as rare as might be expected, study finds published in ‘PLOS ONE’ by Stephanie Drumheller of the University of Tennessee-Knoxville and colleagues.

The term “mummy” is often used to describe dinosaur fossils with fossilized skin, which are relatively rare. It is often suggested that these types of fossils only form in exceptional circumstances and that a carcass must be protected from scavenging and decomposition by rapid burial and/or desiccation for the skin to fossilize.

In this study, Drumheller and colleagues combine the fossil evidence with observations from modern animal carcasses. to propose a new explanation for how such “mummies” might be formed.

The researchers examined a fossil of a dinosaur called Edmontosaurus from North Dakota that retains large patches of desiccated, apparently deflated skin on its limbs and tail. They identified carnivore bite marks on the dinosaur’s skin.

These are the first examples of unhealed carnivore damage to the skin of a fossil dinosaur and, furthermore, it is proof that the dinosaur carcass was not protected from scavengers, and yet it turned into a mummy.

It is known that modern animal carcasses are often emptied because scavengers and decomposers attack the internal tissues, leaving skin and bones behind. The authors propose that damage to this dinosaur’s skin from this incomplete scavenging would have exposed its interior and allowed a similar process to occur, after which the skin and bones slowly desiccated and were buried.

This process, which the authors call “desiccation and desinflammation”, it is common in modern corpses and explains how dinosaur mummies might form under relatively ordinary circumstances.

The authors stress that there are likely numerous pathways by which a dinosaur mummy could develop. Understanding these mechanisms will guide how paleontologists collect and interpret these rare and informative fossils.

Clint Boyd, senior paleontologist at the North Dakota Geological Survey, adds that the mummy has not only taught us that “durable soft tissues, such as skin, can be preserved in partially scavenging corpses, but that these soft tissues are also they can provide a unique source of information about the other animals that interacted with a carcass after death.”