Discover extinct fish lizards 25 years ago

Fish lizards are a giant dolphin reptile that lives in the sea 248 million years ago and went extinct 25 million years ago.

Look for the extinction cause of fish lizards

During the period of the dinosaurs , the fish lizard - a giant marine reptile like a dolphin - flourished in prehistoric oceans. They can live in all near and far water environments. But when it comes to competing in the developed region , this fish lizard loses both its territory and its species before gradually becoming extinct, a new study says.

In fact, the extinction cause of this animal has puzzled scientists for years. Fish lizards evolved from sea-reptile reptiles that existed 248 million years ago. After living along the coast for millions of years, they migrated to offshore waters. They disappeared about 90 million years ago and went extinct 25 million years ago when the meteorite killed the dinosaurs that crashed into Earth.

So, if meteorites are not the cause of the extinction of this fish lizard, then what is the real reason? To get a better understanding, the researchers looked at the fossil specimens of this species and identified the specific types of environments in which the animal lives.

Scientists are studying fossils of fish lizards

In most studies, the habitat of this species is predicted based on a unique characteristic that is usually shaped by teeth, researcher Daniel Dick, a paleontologist at the Natural History Museum in Stuttgart , Germany said. In the new study, scientists are exploiting a number of other features. For example, they analyze the body size and shape of fish lizards to determine their hunting strategy, such as hunting by ambush (poor swimming ability) or chasing children. bait (swim very fast), Dick said.

After examining 45 species of fish lizards, Dick and colleagues, Erin Maxwell analyzed and classified into seven basic groups based on ecological types. For example, in all fish lizards, Cartorhynchus is the only species with a unique ecological type. They are small predators and live in shallow water, Dick told Live Science.

Another group representing most fish lizards is the species that lived in the middle of the early and Middle Triassic period. This species is less than 2 meters long and has a set of blunt but strong teeth. This suggests that they eat hard-shell bait such as corals and shellfish. They do not have elongated bodies and therefore cannot live in offshore waters because they are difficult to swim far away, Dick provides more.

Some types of fish lizards

Not all 7 groups exist at the same time although 5 types exist simultaneously during Jurassic period, the period of the most powerful development of fish lizards. During the Jurassic period, the number of groups of fish lizards decreased. Professional predators like Eurhinosaurus are like swordfish and Temnodontosaurus species that gradually become extinct leaving only two groups living in offshore waters.

The last two groups include 1 species with a large body and strong teeth to crush fish bones or mollusks. The other is quite like a dolphin with small teeth and is capable of eating soft-like prey.

These remnant fish lizards eventually met the limit in the Cenomanian-Turonian extinction event . These include the spinosaurs , plesiosaurs , and about a third of marine animals (invertebrates) that have also become extinct. Since only two species of fish lizards exist, they are easily wiped out.

Until now, scientists still do not understand why fish lizards abandon their previous habitats, they may have been invaded by other species with better adaptability. For example, plesiosaurs have "taken over" many areas near the shore. This research sheds light on the evolution and extinction of ichthyosaurs , Neil Kelley, a researcher at the National Museum of Natural History in Washington, DC, who doesn't participate in research, giving know.