Researchers discover long-lost plaster copies of the Nazi-damaged fossil

It was only "by pure chance" that researchers discovered the casts, during trips in search of early Jurassic ichthyosaur fossils kept "behind the scenes, in the museum vaults," lead study author Dean Lomax told LiveScience, a paleontologist in the Department of Earth and Environmental Sciences at the University of Manchester in the U.K.

“We both looked at each other, and we’re like, ‘Why does that seem familiar?” Dr. Lomax said. “There was just something about this cast,” as per The New York Times.

"Considering that the specimen was originally found in Britain, it would be safe to assume that if any casts were to be located, then in all likelihood, they would be in a museum in the U.K.," Lomax also added.

Ichthyosaurs or "Proteo-saurus"

From around 250 million years ago to approximately 90 million years ago, ichthyosaurs coexisted with dinosaurs and controlled the oceans. They were between 10 to 65 feet (3 to 20 meters) with long, narrow skulls.

An anatomist at the Royal College of Surgeons named Everard Home received the extinct sea reptile in 1818. In an article written in 1819, he gave the specimen the name "Proteo-saurus."

The fossil's destruction during World War II was a blow to paleontology because it deprived future researchers of a specimen that would have benefited in the study of long-extinct species and was rooted in the field's history.

The casts showed that some of those elements were not accurately captured in the surviving artwork. The right femur, for instance, is "more slender, more symmetric, and better defined in the drawing than on the Berlin cast," while the right hind fins bones have characteristics that weren't noted in the illustration, according to the study's authors. 

According to the study, although it is unknown who discovered the fossil in the early 19th century, there is a good chance that it was discovered by English scientist and fossil collector Mary Anning.

Abstract

The first complete ichthyosaur skeleton was introduced to the scientific community in 1819 by Sir Everard Home, and given the name Proteosaurus, although the name was subsequently replaced by ‘Ichthyosaurus’. The skeleton is from Lyme Regis and was probably collected by Mary Anning as it was in the collection of Colonel Birch. The specimen ultimately ended up in the collection of the Royal College of Surgeons, London, where it was destroyed in a bombing raid during World War II. We have discovered two plaster casts of the specimen, although no record exists of casts ever being made. The casts are at the Peabody Museum, Yale University, USA and the Museum für Naturkunde, Berlin, Germany. Significantly, these verify the accuracy of the published drawing of the specimen, and clarify morphologies of some of the bones. Discrepancies between the drawing and the casts are mainly in the details of the forefins and hindfins. The specimen can be assigned to Ichthyosaurus, but the species cannot be determined. This case illustrates the importance of old casts in museum collections. Additional, yet unrecognized casts of this specimen might exist in the UK or elsewhere.