The bucolic English county of Gloucestershire has witnessed an impressive find. A treasure trove of Jurassic fossils , 183 million years old, has been discovered under soil trampled daily by farm animals. Some are surprisingly well preserved.
Among the fossil remains of fish, ichthyosaurs (giant marine reptiles), squid, insects and other ancient animals dating from the first part of the Jurassic period, the fossil of a fish head preserved in three dimensions stands out and belonged to Pachycormus , a extinct genus of ray-finned fish. The fossil, which was embedded in a nodule of hardened limestone protruding from the clay, has amazed researchers at how exceptionally well preserved it is. It contained soft tissues, including scales and an eye . The three-dimensional nature of the specimen’s head and body posture was such that the researchers could not compare it to any other earlier finds.
“The closest analog we could think of was the Big Mouth Billy Bass,” said Neville Hollingworth, a field geologist at the University of Birmingham who discovered the site with his wife, Sally, a fossil preparer and dig coordinator. “The eyeball and socket were well preserved. Normally, in the case of fossils, they are lying flat. But in this case, they were preserved in more than one dimension, and it looks like the fish is jumping off the rock,” Hollingworth said. to Live Science .
“I’ve never seen anything like it,” added Sally Hollingworth. “You could see the scales, the skin, the spine, even his eyeball is still there.”
The Hollingworths were so amazed that they contacted ThinkSee3D, a company that creates 3D digital models of fossils, to make an interactive 3D image of the fish. The idea was to “bring the fish to life” and allow researchers to study it in more detail.
More than 180 fossils have been recorded in the excavation. Most were behind the farm’s barn, which houses longhorn cows with long, curved horns. Many of them closely followed the excavation.
This area of the UK was once under a shallow tropical sea, and it is likely that the sediments found there helped preserve fossils . Neville Hollingworth described the Jurassic beds as slightly horizontal, with layers of soft clays under a shell of harder limestone beds.
“When the fish died, they sank to the bottom of the seabed,” said fossil marine reptile specialist Dean Lomax, a visiting scientist at the University of Manchester in the UK and a member of the excavation group. “As with other fossils, minerals from the surrounding seafloor continually replaced the original structure of the bones and teeth. In this case, the site shows that there was little or no cleanup, so they must have been quickly buried by sediment. As soon as they reached the seabed, they were immediately covered and protected.”
The team has used an excavator to cover 80 meters through the estate’s grassy banks, “removing layers to reveal a small slice of geologic time,” said Neville Hollingworth. Researchers have found that a few specimens are from the Toarcian (a period of the Jurassic that occurred between 183 and 174 million years ago) and included belemnites (extinct squid-like cephalopods), ammonites (extinct shell-on cephalopods), bivalves, and snails, as well as fish and other marine animals.
“It’s important that we can compare these fossils with other Toarcian-age sites, not just in the UK, but across Europe and potentially the Americas,” Lomax said. He pointed to Strawberry Bank Lagerstätte, an early Jurassic site in southern England, as an example.
The group plans to study the specimens further and is working to publish their findings. Meanwhile, the Museum in the Park in Stroud is scheduled to exhibit a selection of fossils.
