More powerful than the straight shell nautilus is the Duns fish.
Duncroaker is a kind of paleontology living in the Devonian period (about 360 million to 415 million years ago), with a body length of about 8 to 10 meters and a weight of up to 4 tons. Its main food is fish and invertebrates protected by hard shells.
The main prey were fishes without hard bones and invertebrates with hard shell protection, such as orthophores and sharks at that time, which were the top predators in the earth's oceans at that time.
About the origin of the name of Deng's fish, someone said that because the fossil of this fish was found, it was called "definitely a fish", and later it was called Deng's fish according to transliteration.
It is considered to be the prehistoric fish with the second largest bite force, and also the largest fish in the Devonian period. According to the research of archaeologists and zoologists, Dendrolimus was almost the dominant fish at the bottom of the sea at that time, and was a top marine predator.
After the extinction event in the late Devonian period, Duncroft was completely extinct. At the same time, the "skull exoskeletonized" shield skin fish represented by Duncroft were completely extinct. Instead, the rectangles and sharks used as its food were transformed into nautilus and modern sharks and survived until now.