Researchers have found fossils of Ionoscopiformes that are 242 million years old in the Triassic strata in Panxian county, Southwest China’s Guizhou province, according to the Institute of Vertebrate Paleontology and Paleoanthropology under the charge of the Chinese Academy of Sciences on February 4.
The fossils of Ionoscopiformes belong to the Halecomorphi taxon of bony fishes and are classified as a new Ionoscopiformes species named Panxianichthys imparilis. It is the most primitive Ionoscopiformes species found so far. Halecomorphi includes Semionotiformes, Ionoscopiformes, Amiiformes and Amia calva. Amia calva are also called dogfish and are the only species of Halecomorphi still alive, inhabiting freshwaters in America.
The intact fossils found in the Triassic strata in Panxian come from a new species that lived in a period later than Robustichthys, but 90 million years earlier than other Ionoscopiformes from the European Jurassic period and American early stage Cretaceous.
The research shows that Panxianichthys imparilis possesses evolutionary characteristics that other Ionoscopiformes species have, such as the sensory part on the upper jaw bone. However, some other primitive characteristics remain.
