In 2009 a team of scientists found in Jaén the remains of the species of turtle that until now was considered the oldest in southern Europe, dating back to about 160 million years. However, by re-studying these fossils, a Spanish researcher has proven that it is not a new species, but a group of very diverse turtles in Europe during the Jurassic period that became extinct due to variations in the level. from the sea .
Not much is known about the oldest sea turtles that inhabited Europe millions of years ago. The discovery in the Betic mountain range, in the province of Jaén, of the remains of a supposed new species – Hispaniachelys prebetica -, considered the oldest in the south of the continent , pointed out new clues but without making it clear to which group it belonged. To clarify this question, the researcher from the Evolutionary Biology group of the UNED Adán Pérez-García studied the fossils that had not yet been analyzed from the specimen and provided new information that gives a twist to what was known about the morphology of these reptiles .
According to Pérez-García, Hispaniachelys prebetica cannot be recognized as its own species, but rather belongs to a group of exclusive tortoises from the European Jurassic called Plesiochelyidae , among which there was great diversity. Their study shows that some of the characteristics of Hispaniachelys prebetica , such as the large size of the carapace, did not differ from the tortoises of the Plesiochelyidae group. According to the researcher, Hispaniachelys prebetica is no longer considered a valid name; it would be more of a nomen dubium and therefore no more precise assignment can be made than indeterminate Plesiochelyidae.
About 160 million years ago, in the waters of the present United Kingdom, France, Switzerland, Germany, Portugal and Spain lived a group of primitive turtles called plesioquélidos, that do not resemble any of the present ones. In Spain they were represented by several species, several of them recently identified and of which there is abundant material. Now, with the identification of the specimen from Jaén, its record is expanded by attributing it to this group.
These European reptiles inhabited the warm and shallow seas of the continent , but they were not as agile in those environments as are the current sea turtles, capable of traveling enormous distances and crossing seas and even oceans. Due to their anatomy, these Jurassic tortoises were restricted to the coastlines.
Due to their dependence on coastal environments, changes in sea level that occurred at the end of the Jurassic – about 145 million years ago – drastically affected their habitats . For these those turtles, like other groups of marine reptiles, became extinct at that time.
