Long-ignored ichthyosaur determined to be new species

Oct. 10 (UPI) -- Fresh analysis of a long-ignored ichthyosaur -- relegated to museum storage closets for decades -- revealed the fossil specimens to represent a new species.

The ichthyosaur, a dolphin-like marine reptile, was originally discovered in 1979 by British palaeontologist Robert Appleby, who named the new species Protoichthyosaurus. But Appleby's peers dismissed his discovery, suggesting the species was identical to a common ichthyosaur named Ichthyosaurus.

When a team of paleontologists from England and the United States took a fresh look at Ichthyosaurus and Protoichthyosaurus, they found several differences, including the number of bones in front fin. The two species likely used their fin differently while swimming. Researchers also discovered differences in the two species' skull structures.

When researchers surveyed Protoichthyosaurus specimens, they realized they'd not only confirmed the species' uniqueness, but had also revealed a bit of scientific forgery. Several Protoichthyosaurus specimens featured an isolated fore fin from Protoichthyosaurus specimens, attached to make the skeletons look more complete.

The fake fins distracted from and disguised actual differences between the two types of ichthyosaur. Thus, Appleby's fakery may be responsible for the dismissal of his discovery.

"In some instances, an isolated fin of an Ichthyosaurus had been added to a Protoichthyosaurus skeleton to make it appear more complete, which led to the genuine differences being missed," Dean Lomax, a researcher at the University of Manchester, said in a news release. "This has been a major problem because it stopped science from progressing."

Researchers described their discovery in a new paper published this week in the Journal of Vertebrate Paleontology.

During their survey of museum collections, researchers teamed up with Rashmi Mistry, an undergraduate student at the University of Reading, who had been studying an unusually small ichthyosaur.

"Whilst doing my dissertation in 2016, I studied several ichthyosaurs in the collections, including a very small skeleton," Rashmi said. "It had an unusual forefin that matched Protoichthyosaurus, which I understood to be a widely unrecognized genus. However, when I contacted Dean, he was very excited. He told me that this little skeleton is the only known small juvenile Protoichthyosaurus."

Their survey ultimately turned up 20 Protoichthyosaurus specimens. The Jurassic era specimens were dated between 190 million and 200 million years old. The survey also turned up a third species, Protoichthyosaurus applebyi, with a unique skull and humerus.