Mysterious fish 50 million years old found modern relatives

Donald Davesne and Giorgio Carnevale have published a paper describing their analyses of two known fossil specimens of this fish on the bioRxiv server.

The fossil of this fish was first found in northern Italy in the 1700s. Its appearance was so unusual that no scientist had been able to classify it. Although it was obvious that it was a new species, no one was able to determine its family. The naturalist Giovanni Serafino Volta, in an attempt to clarify the matter, assigned the fish to the genus Pegasus, which includes sea moths.

Over time, other experts began to doubt the correctness of this classification, as theappearance of the fish did not correspond to sea moths at all. However, even after a second specimen was found, no one was able to propose a better classification and the fish remained in the genus Pegasus.

In their new study, palaeontologists conducted a detailed examination of both fossils in the hope of determining the fish's true place on the evolutionary tree of life. The scientists used ultraviolet light and a stereomicroscope to analyse them more closely, allowing them to rule out the possibility that the fish belonged to the paddlefish family, as some researchers have suggested.

The team of scientists also noted similarities between the fossils and the larvae of fish from the Teleostei group. Many fish in this group have long dorsal fins similar to those of this ancient fish. Another feature was the presence of a thick abdomen, indicating a cavity for internal organs, which also links it to Teleostei.

However, the researchers found no evidence that these fossils belonged to larvae. Their large size and ossified skeleton rather indicated that they were adults. Nevertheless, scientists have speculated that the fish may have simply retained larval features into adulthood.

Although palaeontologists have not been able to establish an exact link between these fossils and other fish species, they are confident that these ancient specimens deserve a new genus. The scientists plan to announce the new genus name when their work is officially published.