New research suggests that the group of ancient ‘sea monsters’ in the United Kingdom has been mislabelled for more than two centuries.
In the early 1800 the fossilised skeletons of marine reptiles were found in Street – which is a village in the county of Somerset, England. The scientists back then named the marine reptiles, ichthyosaurs, which stands for ‘fish lizards’ in Greek.
Judy Massare, a professor of geology at State University of New York College at Brockport in New York, said that the fossils were usually bought by rich gentry and placed in large wooden frames.
At that time, fossil experts said that the reptiles belonged to the same species, called Ichthyosaurus communis – a species form the Late Triassic and Early Jurassic periods. Although some private collectors such as the Clarks family, of Clarks Shoes kept the fossils, most of them were reassigned to museums around the United Kingdom.
Dean Lomax, a palaeontologist at the University of Manchester started the new research when he came across an ichthyosaur skeleton at the Doncaster Museum and Art Gallery in the United Kingdom.
Massare and Lomax analysed the bones and found that the specimen – that dates back 189 million years ago – was in fact a new species of ichthyosaur. It had a visibly larger body length than Ichthyosaurus conybeari and smaller than Ichthyosaurus communis. The researchers named the species Ichthyosaurus anningae.
A further analysis of the other ichthyosaurs from Street revealed that many of them had been mislabelled. The group (that the researchers analysed) had three to four different species of ichthyosaurs, according to Massare.
“One species that we used to think was extremely variable only looks variable because we were combining a couple of other species. We’re trying to figure out the boundaries between those different species,” Massare said.
The differences in the shape of the fore-fin suggest that the various species did not have the same swimming abilities, and the difference in tooth shape, means that they each ate other types of prey, the researcher said.
The findings were presented October at the 75th yearly Society of Vertebrate Palaeontology conference, held in Dallas, Texas.
Image Source: ichthyosaurs