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Nature

Outstanding Jurassic Fossils Rediscovered After More Than 100 Years

author

Stephen Luntz

Freelance Writer

clockJul 24 2015, 00:26 UTC
1291 Outstanding Jurassic Fossils Rediscovered After More Than 100 Years
Artist's impression of Strawberry Bank 183 million years ago. J. Sibbick.

Some of the greatest English fossils found in the 19th Century have been rediscovered. Sadly the site where they were located is now inaccessible, but the superbly preserved relics of the early Jurassic represent a treasure trove for paleontologists.

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In the 1840s the great British geologist Charles Moore noticed some school boys at Strawberry Bank, Somerset, kicking a strangely rounded boulder between them. When Moore opened the boulder he found an ancient fish preserved in three dimensions inside.

Moore collected hundreds of fossils from the same site over the next two decades, before it was built over. However, most of this precious cargo has sat for 150 years in the Bath Royal Literary and Scientific Institution (BRLSI) neglected and largely forgotten. Despite occasional scientific papers on a few of Moore’s finds, the majority have been unstudied until now.

Now, BRLSI curator Matt Williams has rediscovered Moore’s collection, bringing it to the attention of Professor Michael Benton of Bristol University. Together the two have published a study of the specimens in the Journal of the Geological Society.

“When Matt first showed me the fossils I couldn't believe it,” said Benton. “There are 100 nodules containing a large fish called Pachycormus, five or six tiny marine crocodiles, and two species of ichthyosaurs. There are also early squid with their ink sacs and other soft tissues preserved, and hundreds of insects that had flown out over the shallow, warm seas of the day.”

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So far Benton and Williams have barely scratched the surface of what Moore collected from the Strawberry Bank site, but already report, “Marine nektonic animals, including ichthyosaurs, crocodiles, fishes, cephalopods and crustaceans, together with abundant remains of insects from the nearby land.” A £250,000 grant from the Leverhulme Trust has been obtained to allow for a much more extensive study of the remaining fossils.

(a) and (b) The skull of a juvenile ichthyosaur, Hauffiopteryx typicus. (c) Articulated juvenile ichthyosaur, Stenopterygius triscissus. (d) Skull of a subadult thalattosuchian crocodile Pelagosaurus typus. (e) Articulated infant thalattosuchian Pelagosaurus typus. Williams et al.

Such a wide diversity of species is valuable in itself, but two things make the site particularly important. Some of the fossils preserve soft animal parts, as well as bones, teeth and shells. Even more unusually, the paper notes, “Many are preserved in three dimensions, allowing unique access to anatomical details otherwise unknown from other Early Jurassic faunas.”

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Using a combination of U-Pb radioisotopes and magnetic polarity, Williams and Benton dated the Ammonite zone, from which many of Moore’s finds come, at 182.7 million years ago, a time immediately after a catastrophic global reduction in marine oxygen and wild swings in temperature.

While the eight ichthyosaurs may have the widest appeal, Williams and Benton draw particular attention to the well-preserved beetles found at the site, part of a collection of more than 800 insects.

The distribution of specimens by species also shows an interesting contrast with other fossil deposits of the same era. The vertebrates at Strawberry Bank are dominated by Leptolepis and Pachycormidae fish, which make up far smaller proportions of finds at comparable sites. Similarly, the overwhelming bulk of insects are Coleoptera, proving that even in the Jurassic, the Lord had an inordinate fondness for beetles.

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Fishes from Strawberry Bank. (a) Pachycormus; the degradation of the body to the anterior and the exposed phosphatized gut towards the ventral margin should be noted. (b) Complete specimen of Leptolepis; (c) Pachycormus macropterus; the perfectly preserved branchiostegal bones and the lack of compressional distortion should be noted. (d) Abdominal scales of P. macropterus. (e) Pectoral fin of P. macropterus.  


Nature
  • fossils,

  • jurassic,

  • strawberry park

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