A Victorian fossil mystery

The ichthyosaur specimen before conservation (1750 mm by 720 mm by 70 mm)

Ichthyosaur after conservation showing head from separate individuals, and paddle bones set in plaster

Press coverage of the story

Routine conservation of the fossil collections at Amgueddfa Cymru, revealed a specimen that, on first examination, appeared to need a small amount of remedial work. What was to have been a small job turned into a major conservation project which attracted international media interest.

The ichthyosaur

The specimen in question is an ichthyosaur, a marine reptile that lived during the Mesozoic Era, 65-200 million years ago - the same time as the dinosaurs. They are similar to dolphins, with large eyes and distinctive long jaws with sharp teeth and limbs modified into paddles.

The specimen was donated to the old Cardiff Museum in the 1880s and subsequently became part of the National Museum collections. It was originally mounted in plaster with a surrounding wooden frame and then both the plaster and the specimen were painted.

The specimen was restored several times during the twentieth century, and this included new plaster and repainting. A label identified the species as Ichthyosaurus intermedius, collected from Street, Somerset, and described the skeleton as 'the greater part of a small individual preserved with but little disturbance of the bones' — a statement later found to be rather inaccurate.

A detailed investigation of the specimen was undertaken and extensive damage was discovered, with cracks running through it. The plaster and wooden mount were in poor condition so the decision was made to remove all restoration and paint, and to get back to the original skeleton and rock. It was not a decision made lightly because we knew that the whole appearance of the specimen was going to be radically altered.

Revealing the specimen

Removal of the paint layers revealed that the missing ends of the ribs had been moulded in plaster and then painted to match the rest of the specimen, giving the false impression of actual bones.

Study of X-rays taken of the specimen revealed an inconsistency in one section of the spine of the fossil; a dark shadow surrounded the bones. When the paint from this area was removed, it became clear that a channel had been carved in the rock and individual loose bones had been fixed into it with plaster.

Beneath the paint it was discovered that the bones of the single preserved front paddle were also set in plaster. Holes in the surrounding rock suggest areas from which bones may have been removed before being relocated, but it is possible that some bones had been taken from other specimens.

The biggest surprise came when the paint was removed from around the jaw; the rock was a totally different colour and type to the rest of the skeleton. Not only were there at least two individuals involved, but further study proved that the head and body were two entirely different species of icthyosaur! This was a specimen that had been considerably altered by the Victorian preparators.

Re-displaying the conserved fossil

Although the specimen was made up of two different species, it was decided that the head and the body should be kept together as originally intended. The plaster surrounding the paddle and a part of the ribs made from plaster were also left intact. A new light-weight support system was built. Instead of being displayed simply as a museum specimen, this ichthyosaur will be used to highlight the techniques used by some Victorian enthusiasts to 'restore', display and present fossil specimens and how painstaking conservation work today revealed the true nature of our specimen.

Intense media interest was sparked when the Museum announced a public talk on the conservation of the specimen. This resulted in the story being covered in the national and international press in addition to television, radio and the internet, and included a live interview with ABC Radio in Australia!