A newly discovered ancient aquatic creature belongs to a group of cartilaginous fish similar to sharks known as Hybodontiforms, which lived during the early age of dinosaurs.
According to Sci-News, the new species Parvodus ominechonensis thrived during the late Triassic period (from 237 to 227 million years ago).
It is part of Parvodus, a genus of the extinct cartilaginous fish branch Hybodontiform, as reported by a research team from the National Museum of Nature and Science in Japan.
The aquatic creature Parvodus ominechonensis and its Hybodontiform lineage closely resemble modern sharks and share a common ancestor – (Graphic: Jorge Blanco).
Several distinct teeth of Parvodus ominechonensis were collected from the Momonoki Formation in the town of Omine-chō, Yamaguchi Prefecture, Japan.
However, the rock layers containing these teeth once belonged to an ancient shallow sea, which is also the type of terrain where other Hybodontiform fossils have been excavated.
Excavated fossil parts – (Photo: Breeden III and colleagues).
The Hybodontiforms thrived throughout the Devonian, Carboniferous, Permian, Triassic, Jurassic, and into the Cretaceous periods before becoming extinct.
This branch of cartilaginous fish is closely related to modern sharks and rays (the Neoselachii branch).
The earliest known fossils of the Hybodontiform lineage date back to the Mississippi period (USA). Other species within the genus Parvodus have been found in China, also dating to the Triassic period.
Additionally, several other Parvodus species have been discovered across the Northern Hemisphere and South America, dating back to the Cretaceous period.
Thus, the new species found in Japan contributes to the assertion that this lineage of cartilaginous fish diversified and spread widely over hundreds of millions of years.
According to the publication in the Journal of Vertebrate Paleontology, Parvodus may have originated from a freshwater habitat in present-day South China when it was still part of the ancient supercontinent.
This genus may have emerged after the mass extinction at the end of the Permian period and diversified in East Asia during the Triassic period before spreading globally.
