NB Published in revised edition, with photographs, in Deposits geological magazine,Issue 17/Winter 2009.
ISSN: 17449588
PDF and print back copies are available from the Deposits website :http://www.depositsmag.com/

Denizens of the Oxford Clay.

Britain is the birth-place of palaeontology, and the heady years of the 19th century saw the discovery of creatures that have defied the imagination of small boys –myself included- for over 150 years since. I’m talking, of course, about the dinosaurs.
A vast plethora of names abound for the various scraps of bone that were discovered in those days, and unfortunately many finds today still suffer from this taxonomical mess. Fortunately however the British dinosaur scene is undergoing something of a revival with new research and, more importantly, new finds coming to light. This is the story of one of those finds and the bigger picture it fits into.

‘PFL 03’ is probably not the most exciting name in the world. I came up with it, and even I agree it is fairly dull. This however is the catalogue number for a small bone that thudded to the floor inside a parcel this August. The parcels various contents were the result of a trade with Fiona Jennings (a fellow fossil-hunter), and the small bone was thrown in due to the lack of Ichthyosaur material (my other favourite interest). Secure inside a foam-padded plastic box, the attached label read ‘Plesiosaur vertebra, Old Flyover Ashpit, Nr A15, Fletton, Peterborough. Lower Oxford Clay. 14/09/03’. At least, that is what it read after I retrieved the parcel from my next door neighbour! A slight communication failure!
Not having much experience of the Oxford clay, I dug out a few books and began to skim through them. I chanced across a plate of Stenosaurus, a rather ferocious looking marine crocodile, and found a vague similarity between the two bones. That was enough for me, so I wrapped it up and decided to take it with me into town.
Cambridge is a wonderful place, from both historical and architectural points of view. But perhaps the best thing about it are the various free university museums, - and of these there is one I’m quite often found in. The Sedgewick Museum of Geology. Depending on meetings and coffee breaks there is usually someone around to ID finds that are brought in, a service I make regular use of. On this day however, the fossil first drew little but puzzled silence...
... An hour later and I held a receipt to pick up the fossil once it had been identified. Written into the description of find box was ‘Reptile vertebra – Croc or Dino?’...
The Oxford clay lies across a vast swathe of the country stretching from Dorset in the south to Yorkshire in the north. Stretched across two periods of geological time – the Callovian and Oxfordian - it contains an abundance of middle Jurassic marine fossils. It is also known for its occasional – albeit rare- dinosaur remains. The impressive theropod Eustreptospondylus oxoniensis was discovered in 1964 north of Oxford and is one of the most complete European dinosaurs known. Metriacanthosaurus, another British theropod of similar age, is known from a partial post-cranial skeleton and was named in the same year. Other species are known from dispersed and scattered fragments – a spine attributed to the stegosaur Dacentrurus comes from the oxford clay of Weymouth whilst scattered skeletal material forms the basis for the similar creature Lexovisaurus. Presumably the vast majority of dinosaur remains found in these strata originate from corpses washed out to sea, hence the scarcity of finds. The Oxford Clay of Peterborough is certainly marine with oysters of the species Gryphea dilatata abundant, and yet it has its own share dinosaur remains. By the turn of the last century two sauropods, a stegosaur, ankyliosaur and an ornithopod had been attributed to the various clay pits in the area(Leeds 1956; Martill 1988), with the theropod Megalosaurus represented by a fibula (CAMSM J46881) found at Fletton and described by Huene in 1901. Fletton is also the site where CAMSM J46886 was found – a phalangeal bone attributed to Camptosaurus. The Sedgwick museum holds one further bone from the site – a large limb bone referred to as dinosauria indeterminate (CAMSM J46888). Peterborough – and the Oxford clay in general – is no stranger to these denizens of the past.
After leaving the find into the care of the museum it was time for holidays. Over the next four weeks I found Crinoids in Devon, an Ichthyosaur paddle at Charmouth and went hunting from brachiopods, corals and urchins in France. I also received my GCSE results into the bargain. But a month passes slowly when you are itching for a result of a different kind...
The verdict of the Sedgwick museum staff was that it was a distal caudal vertebra belonging to an ornithschian (‘bird hipped’) dinosaur and was an adult when it died. To say I was excited is something of an understatement! I think it’s a good job I took notes as otherwise this article would be fairly short! The small tail bone compared well with the mid -distal caudals of Iguanodon, specifically the 15th caudal (as starting from the sacral end) despite the obvious difference in size. A single ornithopod has previously been noted from near this locality – in 1901 Huene referred an isolated tibia to the small ornithopod Dryosaurus sp. but it has since been decided that the specimen is indeterminate (D.M.Martill/ D. Naish 2001). The author is aware of related recent finds but cannot confirm or discuss them.
For now PFL03 will have to remain nameless. As far as the author is aware, no small ornithschian dinosaur species have been named in Britain for this era, making referral to any species impossible. It is possible it represents a new species - but the material is insufficient to raise a new name on. Further research and (hopefully!) fresh finds would be required. Suffice to say that 154 million years ago a small bipedal dinosaur was running around somewhere near Peterborough. Due to its small size it could have been omnivorous, feeding off available plant and insect material on the various small islands and landmasses that made up the UK. Perhaps it was capable of swimming between these islands whilst in search of food, much as red deer do in the outer islands of Scotland today –or it may simply have been washed out as a carcass that slowly decomposed, hence the isolated nature of the find.
The fossil has been donated to Cambridge Sedgwick museum and the specimen is now in their collection. It is being prepared and I will have a cast returned, whilst the original goes on display. At the time of writing it does not yet have a CAMSM catalogue number.
Explanation of field number PFL03: All specimens are allocated a three letter site identifier and a unique specimen number. In this case ‘Peterborough, Fletton, #03’

During the writing and preparation of this article I have referred to many sources, the most notable of which being SV-POW! (http://svpow.wordpress.com/) for an excellent tutorial on vertebra nomenclature and the comprehensive ‘Dinosaurs of the Isle of Wight’ edited by David M. Martill and Darren Naish (The Paleontological association 2001 – available from UKGE). I also would like to give special thanks to Fiona Jennings for her valuable correspondence and to the staff of the Sedgwick museum for their work on this and other finds.
Robert Broughton - HMV1120@hotmail.com
Throughout this article the abbreviation CAMSM has been used for The Cambridge Sedgwick Museum.

Photo captions:

Ornithopoda incertae sedis. PFL03 in lateral view. Note the prominent projection A (Prezygapophysis) that articulated with the next vertebra behind. The attachment site for a bony chevron can be seen to the bottom right B. The Neural spine is broken along its width but would have extended an estimated 1-2cm C.

Ornithopoda incertae sedis. PFL03 in anterior (rear) view. The wear to the left hand Prezygapophysis is prominent. The neural canal D can be seen but is in filled with matrix. Note the amphicoelous (concave each end) centrum E and chevron attachment site B. All photographs by kind permission of Fiona Jennings.