Shrimp-like fossils are species new to science

Posted by Flora Malein

Scientists have discovered a 425 million year old relative of today’s shrimps and crabs.

The two tiny fossils, that measure just 10mm in length, were found in a bed of rocks in Herefordshire, England. They are remarkably well preserved with an intact shell, body, limbs, eyes, gills and digestive system. This has allowed scientists to identify them as a completely new species of ‘ostracod’ making it a relative of today’s arthropods such as crabs, shrimps and lobsters.
 
The discovery was made by a team of scientists from Leicester, Oxford, Imperial and Yale. The lead author, David Siveter, named the new species after his late wife.
 
"The two ostracod specimens discovered represent a genus and species new to science, named Pauline avibella.  The genus is named in honour of a special person and avibella means ‘beautiful bird’, so-named because of the fancied resemblance of a prominent feature of the shell to the wing of a bird," says Siveter, a professor at the University of Leicester department of geology.
 
The ostracod species would have lived in the subtropical seas that covered southern Britain during the Silurian period of geological time, over 400million years ago. The specimens were frozen for millennia, preserved under a layer of ash from a volcanic eruption.
 
"The find is important because it is one of only a handful preserving the fossilised soft-tissues of ostracods," adds Siveter.
 
"The preservation of soft-parts of animals is a very rare occurrence in the fossil record and allows unparalleled insight into the ancient biology, community structure and evolution of animals - key facts that that would otherwise be lost to science. The fossils known from the Herefordshire site show soft-part preservation and are of global importance."
 
A virtual model of the specimens was constructed out of 500 photographs of crossections of the fossils created by painstakingly grinding them down layer by layer. Each layer of the tiny fossils was only 20 micrometres thick.
 
The findings are published in the journal Proceedings of the Royal Society.