Associate Professor Yasutoshi Nakajima of Tokyo City University and his colleagues have not yet found fossils excavated from the strata of the early Mesozoic era (about 2 million years ago, early Triassic) in Kesennuma City, Miyagi Prefecture. It was revealed that it may be a kind of live reptile.
The Paleozoic marine ecosystem was dominated by Paleozoic fauna such as trilobites, sea lilies and sharks.Most of them were extinct due to the effects of global warming caused by the eruption of Siberian volcano about 2 million years ago, but it is said that new reptiles entered the sea and began to prosper in the early Mesozoic era.Of these, fossils of reptiles with crushed teeth that break hard shells such as invertebrates have been found worldwide in the Middle Triassic strata, but fossils of the Early Triassic are found in Europe and elsewhere. It was limited to North America.
Many fossils from the Paleozoic to Mesozoic eras have been found in the southern Kitakami belt from northern Miyagi prefecture to southern Iwate prefecture.This time, Associate Professor Nakajima collected fossils collected by Toshiyuki Furumura (a student at the University of Tokyo at the time of discovery) from the early Middle Ages exposed on the coast of Osawa, Motoyoshi-cho, Kesennuma City, Miyagi Prefecture. Identified as part of the skull.
Spherical black teeth resembling "tapioca" lined up on the jaws of this fossil, and it is presumed that they used the teeth to prey on invertebrates such as shellfish and crustaceans.In the early Triassic strata of the prefecture, the oldest marine reptiles such as ichthyosaurs have been discovered in the past, but this fossil can be clearly distinguished from these and has not been discovered in Japan. Expected as a kind of marine reptile.
This discovery indicates that marine reptiles that appeared in the early Triassic period diversified their eating habits in a short period of time and complicated the marine food web, resulting in a worldwide extinction of the ecosystem. It is said to be important evidence to support the new idea of a very rapid recovery from the reptiles.
