New research at the University of Leicester has changed scientists’ understanding of how spectacular fossils with delicate soft tissues form.
While most fossils are ‘hard’ tissues, such as bone, shell or teeth, some rare sites around the world had unique conditions that allowed minerals to fossilize soft parts such as skin, muscles and other organs – here Even the delicate eyeballs of some ancient creatures. ,
But one aspect of this rare conservation that has puzzled scientists is why some internal organs seem to be more commonly fossilized than others.
Researchers at the Leicester Center for Paleobiology developed an experiment to study the chemistry inside a rotting fish and mapped the pH levels of its internal organs during two and a half months of carcass decomposition.
Their findings, published today (Monday) in paleontologyShow that the specific tissue chemistry of each organ governs the likelihood of it being replaced by minerals.
This result explains why some tissues more readily turn into calcium phosphate fossils that capture high-resolution details of a creature’s most delicate material, while other organs are lost over time.
Dr Thomas Clements, now from the University of Birmingham, led the study during his time as a PhD researcher at Leicester. he said:
“One of the best ways that soft tissues can turn into rock is when they are replaced by a mineral called calcium phosphate (sometimes called apatite). Scientists have been studying calcium phosphate for decades to understand why. We’re trying to figure out how this process happens – but one question we just don’t understand is why some internal organs are more likely to be protected than others.
“We designed an experiment by looking at rotting fish that were disgusting and smelly, but we made an interesting discovery.
“Organs don’t generate special microenvironments—they all rot together in a ‘soup’. That means it’s the organs’ specific tissue chemistry that governs their likelihood of turning into fossils.”
For a tissue to phosphatize, its pH must fall below pH 6.4. In this acidity, if the fossil is buried quickly, calcium phosphate and other minerals can initiate the fossilization process that preserves the fine details of some soft tissues.
The finest examples of such fossils include the Cretaceous-era octopus of the extinct genus keupia Discovered in Lebanon, estimated to be at least 94 million years old.
Sarah Gabbott is Professor of Paleobiology and a co-author of the paper. Professor Gabot said:
“Seeing and recording (and smelling) how fish decompose may not be what most people think of science, but it is important for paleontologists to understand the process of decay, to reveal how an animal’s What physical features are likely to become fossilized, and what will they look like.
“We were really pleased with the results because we can now explain, for example, why fossils often preserve an animal’s gut but never preserve its liver.”
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