What are the animals called living fossils?

Animals called living fossils include nautilus, horseshoe crab, platypus, Chinese alligator, pike and so on.

Nautilus 1

Nautilus first appeared in Ordovician (about 500 million years ago), and its shape has not changed much so far. It is the oldest extant mollusk species in the world. Nautilus is currently only distributed in the Indian Ocean and the Pacific Ocean.

Step 2: limulus

The horseshoe crab first appeared in Devonian (about 400 million years ago), and there is also a saying that horseshoe crab first appeared in Ordovician, because fossils suspected of horseshoe crab ancestors were also found in Ordovician strata, and once lived in the same era as trilobites. Limulus blood has high scientific research value and can be made into reagent.

3. platypus

Platypus is an endemic species in Australia, which first appeared 25 million years ago. It is a primitive mammal that has not yet fully evolved, with very few species. The platypus can be regarded as one of the ancestors of mammals.

4. Chinese alligator

The Chinese alligator is distributed in the Yangtze River valley of China, which first appeared in Mesozoic (about 250 million years ago). It once lived in the same era as dinosaurs, and still retains some characteristics of dinosaurs.

5. Barracuda

Barracuda is the only all-finned fish in the world, which is distributed in the deep water below 400 meters in the Indian Ocean and the Pacific Ocean. Its ancestors first appeared in Devonian (about 400 million years ago), and a branch of the total fin fish became the earliest amphibian in the world. They are the ancestors of all land creatures later.