Oldest ionoscopiform fish found from the Middle Triassic of South China
Ionoscopiform fishes have been known only from the Late Jurassic of Europe and the Early Cretaceous of the New World, although potential ionoscopiforms based on poorly preserved specimens, questionably assigned in the genus Ophiopsis, have been reported from the Middle Triassic (Ladinian) of Italy and Austria. According a paper published online May 28 in Biology Letters, a new ionoscopiform, Robustichthys luopingensis, from the Anisian (242–247 million years ago), Middle Triassic marine deposits of Luoping, eastern Yunnan Province of China, extends the stratigraphic range of this group by approximately 90 million years, and the geographical distribution of this group into the Middle Triassic of South China. These new data also provide a minimum estimate for the split of Ionoscopiformes from its sister clade Amiiformes and shed new light on the origin of ionoscopiform fishes.