News / University of Bristol
Fossil poo shows fishy lunches in Bristol from 200 million years ago
A new study of coprolites – otherwise known as fossil poo – shows the detail of food webs in the ancient shallow seas around Bristol.
One hungry fish even ate part of the head of another fish before snipping off the tail of a passing reptile.
Marie Cueille, a visiting student at the University of Bristol’s School of Earth Sciences, was working on a collection of hundreds of fish poos from near Chipping Sodbury dated at 205 million years ago.
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She applied new scanning technology to look inside these coprolites and found an amazing array of food remains.
Marie said: “The ancient fishes and sharks of the Rhaetian seas were nearly all carnivores. Their coprolites contain scales, teeth, and bones, and these tell us who was eating whom. In fact, all the fish seem to have been snapping at each other, although the general rule of the sea probably applied: if it’s smaller than you, eat it.”
Food web for the Rhaetian, 205 million years ago, of the Bristol region. The arrows show who eats whom, and red and black means inferred, and blue arrows are based on evidence from coprolites. Credit: Marie Cueille and Mike Benton.
The CT scans of one tiny coprolite, measuring only a centimetre or so in length, contained only three bones: one a highly tuberculated skull bone of another fish, and two vertebrae from the tail of a small marine reptile called Pachystropheus.
Dr Chris Duffin, who collaborated on the project, added: “This shark probably snapped at another fish or scavenged some flesh from the head region of a dead fish.
“But it didn’t just strip off the flesh but swallowed great chunks of bone at the same time. Then it snapped at a Pachystropheus swimming by and had a chunk of its tail.”
Professor Mike Benton, who co-supervised the study, said: “What amazed us was that the bones and scales inside the coprolites were almost completely undamaged.
“Today, most predators that swallow their prey whole, such as sharks, crocodiles or killer whales, have powerful stomach acids that dissolve the bone away.
“These ancient fishes must have had a painful time passing their faeces which were absolutely bristling with relatively large chunks of bone.”
The study has a classical resonance because Rhaetian coprolites from bonebeds near Bristol were some of those studied by William Buckland in the 1820s when he invented the name ‘coprolite’.
Buckland was professor of geology at Oxford University and pioneered the use of coprolites to reconstruct ancient food webs, also collecting specimens from the Jurassic around Lyme Regis – many of which were supplied by famous fossil collector Mary Anning.
Main image: CT scan of coprolite specimen, BRSMG Cf15546, in different views, showing tuberculated bone (blue) from a fish skull, and two vertebrae from the tail of the marine reptile Pachystropheus, in yellow and green. Credit: Marie Cueille, and Palaeobiology Research Group, University of Bristol.
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