Ten rare ancient creatures are giant shrimp, giant horseshoe crab, giant dragonfly, giant snail, giant sea scorpion, land killer scorpion, corner stone, giant centipede, giant clam and ancient centipede worm.

1. Macrobrachium giganteum

Macrobrachium giganteum is a very peculiar ancient creature, which has the characteristics of both squid and shrimp. Its body length is up to 1 meter, and its mouth is covered with sharp teeth. The fossil of Macrobrachium giganteum was found in China, and it was an ancient underwater arthropod, living about 5 million years ago.

It probably feeds on small crustaceans and swallows them with sharp teeth. Its teeth are like serrated knives, and its powerful jaws can catch larger prey.

2. Giant horseshoe crab

This is the largest trilobite species discovered so far, with a body length of 6 cm. They lived in the Paleozoic era about 5 million years ago and devoured rotting biological corpses on the seabed.

It is very similar to horseshoe crab, with a thick armor shell and compound eyes, and its body is segmented. Giant horseshoe crab and other trilobite species are relatively simple and adaptable creatures, which have survived for 3 million years.

3. Giant Dragonflies

Modern dragonflies are small in size, but their ancestors were very large. In ancient times, giant dragonflies had a wingspan of 6 cm and a body length of nearly 4 cm.

This huge body led researchers to guess that it might feed on animals the size of frogs and squirrels. The reason for the extinction of this huge prehistoric dragonfly is that the oxygen content of the earth's atmosphere began to rise millions of years ago.

4. Giant Snails

The largest snail species today is the African giant land snail, with a body length of 18 cm and a shell diameter of 9 cm. However, their prehistoric giant snail, Giganteum, is considered to be the largest snail in the history of the earth, with a body length of nearly 6 cm. Paleontologists believe that they lived in the Eocene ocean 5 million years ago.

5. Giant sea scorpion

The giant sea scorpion fossil was first discovered in Germany in 27, and its body length reached 2.4 meters. In fact, the length of only one pliers exceeded 46 centimeters. This species disappeared in the Permian period 25 million years ago.

6. The land killer scorpion

kirktonensis is another ancient scorpion species. They lived on land, and their body length can reach 6 cm. They lived in Devonian about 4 million years ago. It is likely that they ate small arthropods and insects, and their bites were enough to kill some animals.

7. Cornerstone

Judging from the remains of Cornerstone, its body length can reach 9 meters. It may be the largest marine predatory species in Paleontology. They searched for food in seawater and ambushed their prey. According to the analysis of paleontologists, it is basically a blind creature, like a modern close relative species, Nautilus, which is an ocean floater.

8. Giant centipede

Euphoberia is very similar to modern centipede in appearance and behavior, but the difference is that its body length is more than 1 meter. Archaeologists have found this ancient giant centipede fossil in Europe and North America, but scientists are not sure about their food. In contrast, modern centipedes are only 25 cm long and can prey on birds, snakes and bats.

9. Giant clam

platinus is one of the largest bivalves in the history of the earth, with a body length of 3 meters. In contrast, their volume is 2.5 times that of modern large clams.

1. Ancient centipedes

Ancient centipedes are ancestral species of centipedes and millipedes, with a body length of more than 2.4 meters. They are fat ancient creatures and one of the few invertebrate predators found so far. They lived from Carboniferous to early Permian, and lived in present-day North America and Scotland about 3 million years ago.