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: wessexcoastgeology.soton.ac.uk/pyrenbib.htm. Southampton University.

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

James Havard - Jimhhavard@hotmail.com

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