Fossils Shed Light on Evolution of Flying Fish

Discovery of new fossils in southern China suggests that the first flying fish may have evolved to escape from predators, say researchers.

A team of researchers analyzed the fossils of an ancient fish that was found during an excavation in southwest China in 2009. The new findings from the fossil of a marine fish, Potanichthys xingyiensis, sheds light on the evolution of prehistoric flying fish.

The specimen lived during the Middle Triassic period about 235 million to 242 million years ago in what researchers call as the Yangtze Sea. According to the researchers, the sea was once part of the Paleotethys Ocean that was located in the region where the Indian Ocean and Southern Asia are currently located, reported LiveScience.

Up until the fossil discovery in China, there were no fossil specimens of the flying fish older than 65 million years. The newly found flying fish fossil suggests that gliding on water evolved much earlier than previously thought. However, modern flying fish do not seem to descend from this old specimen, and they may have evolved their flying abilities independently.

This could mean that flight evolved at different times in the history of fish. Researchers noticed that the fish had large pair of pectoral fins, which could have worked as wings. The fossils are four-winged, which suggests that the fish could have evolved to take long-distance flights, a report in NewScientist said.

Fossil evidence belonging to the extinct group of fish known as the thoracopterids (Potanichthys also belongs to this group) were earlier found in Austria and Italy. The new discovery suggests that the fish and other forms of life were once spread from the west to the east of the Paleotethys Ocean (what is now Europe to Asia).

"In modern ecosystems, due to limitations of muscle function, flying fishes are unlikely capable of flight at temperatures below 20 degrees C (68 degrees F)," researcher Guang-Hui Xu, a paleontologist at China's Institute of Vertebrate Paleontology and Paleoanthropology in Beijing, told LiveScience.

"We can reasonably apply similar limitations to the Triassic thoracopterids, and we suggest that Potanichthys adds a new datum supporting a generally hot climate in the Middle Triassic eastern Paleotethys Ocean," he said.

Potanichthys is believed to have lived some 10 million years after end-Permian mass extinction, which happened some 250 million years ago. More than 95 percent of the species had vanished during the mass extinction. The recovery after the extinction was believed to be slower, the LiveScience report said.

However, the new evidence of over-water gliding in vertebrates suggests that recovery after the mass extinction was more rapid than previously thought.

The complete details of the study are published in the journal, Proceedings of the Royal Society B.