Jul 28, 2015

Mr Leeds and the Problem Fish


The Sedgwick Museum recently acquired an exciting new specimen of Jurassic fish Leedichthys problematicum, the biggest bony fish that ever lived!
Category: July 2015
Posted by: Sarah

The bones were discovered by Mr Michael Challen of Nottingham, a keen fossil collector, who sadly passed away late last year. He discovered the fossil bones in a quarry near Peterborough.
Since the 19th century workmen have quarried the fine black clays around Peterborough for brickmaking. These mudstones, known to geologists as the Oxford Clay, were laid down in a shallow continental sea around 160 million years ago. They contain the fossil remains of plants and animals that lived at that time, including marine crocodiles, ichthyosaurs and ammonites.

Leedsichthys (“Leeds’ fish”) is named after Alfred Leeds, another collector who scoured these same Peterborough clays for fossil bones and shells 150 years ago. It was called problematicum, because palaeontologists initially found it difficult to interpret what it was. They thought that the large flat bones of the head were actually the back plates of a dinosaur like Stegosaurus!

The Sedgwick Museum already has some Leedichthys bones, collected by ex-Curator Henry Keeping in 1900. According to Leedsichthys expert Dr Jeff Liston, the Challen Collection includes some parts of the skeleton that we don’t have, so on his recommendation we decided to accept the donation.
Museum Collections Assistant Matt Riley was excited at the prospect of acquiring more Leedsichthys bones, as he has a personal interest in this species, having discovered another skeleton of the same during student fieldwork in 2001 (this specimen resides in Peterborough Museum).
Matt and colleague Sarah Finney collected the specimen from Sherwood Forest, where it was being looked after by the fossil sellers and expert preparators at Stone Treasures (http://www.fossils4sale.co.uk/). (Thankfully, they made it out of Sherwood Forest and safely back to Cambridge without being accosted by hooded bandits).
The specimen must now be condition checked and catalogued before we decide if it will go on public display.
If you would like to see what else has been discovered in the Oxford Clay of Peterborough there are many exciting specimens exhibited in the Sedgwick Museum gallery.


Photo credits
Image 1 - Leedsichthys 1: 17 boxes of fossil bones arrive safely at the Museum Conservation Lab.
Image 2 - Leedsichthys 2: Large head plate with clear growth bands.
Image 3 - "Reconstruction of Leedsichthys in life (Credit: Dmitry Bogdanov -http://dibgd.deviantart.com/)."