Introduction

In the course of undertaking a university independent mapping project in the Catalonian Pyrenees a vertebrate fossil with vertebrae and ribs was found. The location is Llobregat River east of Guardiola de Bergueda. The specimen was discovered in Roda Marls of Eocene age (Hartevelt, 1970) by Southampton University graduates, Nicholas Hartwell and James Havard. The formation consists mainly of light grey, fine grained, fissile marls interbedded in regions with medium sand beds as part of a thrust-generated, turbidite sequence. Hartevelt (1970) considered these Roda Marls to be of Upper Lutetian to Bartonian (Upper Ledian) in age.

Description of the Specimen

As seen in the photographs the specimen lacks head remains becauses of recent erosion by the river. The skeleton is phosphatic and exceptionally well-preserved. When pieced together, it is 1.5 metres in length and 0.2 metres in width (at the level of its rib cage). The spinal column is unusual, containing procoelous vertebrae with tall, ornamented neural spines, which are 3 centimetres in length and 1.5 in width. The ribs are long and slender and curve in a pronouced manner towards the tip of the tail.

Identity of the Vertebrate

In the field the specimen was, at first, thought to be the remains of a fish but the character of the vertebrae is evidence against this. A crocodilian origin was considered but there are no scutes. Dr Angela Milner of the Natural History Museum, London was sent a photograph and commented that although the specimen was has similar neural spines to that of a crocodile, the slender curved ribs are thought to be more characteristic of Choristoderes. The Suborder Choristodera belongs to the Order Eosuchia and the choristoderes are found in Upper Cretaceous and Eocene strata (Romer, 1945). No more precise identification has yet been established.

An email was received from Daniel Ksepha on 15 April 2005. He helpfully commented that although he had worked on choristodere material in his research he doubted whether the specimen belonged to the group. This is because of the procoelous vertebrae present in the specimen.

Any further suggestions as to its identity would be appreciated.

Acknowledgements

The authors thank Dr Angela Milner for examining an image of the bones and commenting on their possible identity. They thank Barry Marsh for photography. We thank Daniel Ksepha for his helpful comments.

References

Hartevelt, J.J.A. 1970. Geology of the upper Segre and Valira Valleys, Central Pyrenees, Andorra/Spain. Leidse Geologische Mededelingen, 45, 167-236, published separately 24-11-1970.

Romer, A.S. 1945. Vertebrate Paleontology. The University of Chicago Press, Chicago, Illinois, 687pp.

West, I.M. 2005. Select Bibliography of the Geology of the Pyrenees. Internet Site: www.southampton.ac.uk/~imw/pyrenbib.htm. Southampton University.

Nicholas Hartwell - Nick.Hartwell@fruitcake.co.uk

James Havard - Jimhhavard@hotmail.com

and

Copyright © 2013 Ian West, Catherine West, Tonya Loades and Joanna Bentley. All rights reserved. This is a purely academic website and images and text may not be copied for publication or for use on other webpages or for any commercial activity. A reasonable number of images and some text may be used for non-commercial academic purposes, including field trip handouts, lectures, student projects, dissertations etc, providing source is acknowledged.

Disclaimer: Geological fieldwork involves some level of risk, which can be reduced by knowledge, experience and appropriate safety precautions. Persons undertaking field work should assess the risk, as far as possible, in accordance with weather, conditions on the day and the type of persons involved. In providing field guides on the Internet no person is advised here to undertake geological field work in any way that might involve them in unreasonable risk from cliffs, ledges, rocks, sea or other causes. Not all places need be visited and the descriptions and photographs here can be used as an alternative to visiting. Individuals and leaders should take appropriate safety precautions, and in bad conditions be prepared to cancell part or all of the field trip if necessary. Permission should be sought for entry into private land and no damage should take place. Attention should be paid to weather warnings, local warnings and danger signs. No liability for death, injury, damage to, or loss of property in connection with a field trip is accepted by providing these websites of geological information. Discussion of geological and geomorphological features, coast erosion, coastal retreat, storm surges etc are given here for academic and educational purposes only. They are not intended for assessment of risk to property or to life. No liability is accepted if this website is used beyond its academic purposes in attempting to determine measures of risk to life or property.

Webpage - written and produced by:

Ian West, M.Sc. Ph.D. F.G.S.

.

at his private address, Romsey, Hampshire, kindly supported by Southampton University,and web-hosted by courtesy of iSolutions of Southampton University. The website does not necessarily represent the views of Southampton University. The website is written privately from home in Romsey, unfunded and with no staff other than the author, but generously and freely published by Southampton University. Field trips shown in photographs do not necessarily have any connection with Southampton University and may have been private or have been run by various organisations.