Scientists study rotten fish to create image of ancestors
By Dr Sarah Gabbott
University of Leicester
Scientists show a fish rotting over 200 days in seconds as part of a study
I am one of the scientists at the University of Leicester who has been studying the way primitive fish decompose to gain an impression of our early ancestry.
We, the Leicester team, believed that examining the process would help us reconstruct an image of creatures that existed 500 million years ago.
In a way our experiment is similar to those going on at the 'body farms' in the USA, where human corpses are left to decompose so forensic scientists can determine time and cause of death.
But, as palaeontologists, we want to uncover what an animal which lived 500 million years ago looked like before it died.
Dr Gabbott on the study
Dr Mark Purnell, who's an expert on early vertebrate fossils, and I got together over a coffee two years ago to discuss the problem of trying to reconstruct such ancient creatures from only their rotted remains.
It was a real conundrum. Like forensic scientists we realised that if we could undertake a series of controlled laboratory experiments rotting primitive fish we may find the solution.
We were looking at the patterns and sequence of loss anatomical information during decay
Dr Gabbott, University of Leicester
The experiments were actually quite simple in design.
We were joined by Dr Rob Sansom, who went to the fjords of Sweden and the streams of England to collect the 'living fossils' that we decayed - hagfish and lamprey respectively, both jawless fish.
We decided to decay hagfish and lamprey as these are primitive and not a million miles away in their anatomy to those very early vertebrates that swam in the sea half a billion years ago.
Rob had the unenviable task of actually watching the primitive fish rot and noting how they changed during decomposition.
We were looking at the patterns and sequence of lost anatomical information during decay. By looking at these patterns, we were able to identify potential sources of bias in the preservation and interpretation of early vertebrates.
For example, we can distinguish those fossils that have true evolutionary significance from those that might simply represent the decayed remains of a different animal.
So by comparing how the features of hagfish and lamprey look after various intervals of decay we could look at the fossils and reconstruct what they would have looked like before decay effected them.
It might not be surprising that rotting fish are extremely smelly, but it is more surprising that they can unlock important information about how the earliest vertebrates looked and how they evolved.
So now Mark, Rob and I can start to understand how they fit into the tree of life and trace back our ancestry over 500 million years ago.
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