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Devonian Period: When “King of the Sea” Dunkleosteus Ruled the Oceans

The Devonian Period, which dates back 390 million years ago, is the fourth era of the Paleozoic Era in ancient times. There were many weird fish-shaped animals in the oceans of this era, so the Devonian period is also called the “Age of Fishes.”
1. “King of the Sea” Dunkleosteus

Dunkleosteus lived about 360 million to 415 million years ago, 175 million years earlier than the birth of the first dinosaur on land. It was the largest carnivorous bony fish in the Devonian period. Its back is darker in color and its belly is silver. It is 8 to 10 meters long and weighs 4,000 kilograms.

Dunkleosteus gives people an unusually ferocious look, with a shark-like spindle-shaped body, very strong, and its head and neck are covered with a thick and hard exoskeleton.

Dunkleosteus generally lives in shallower waters in Europe, Africa, and North America. It is a carnivore. Its main food is sharks, bony fish, trilobites, ammonites, nautiluses, and placoderms. It is protected by a hard shell. of fish and invertebrates.

In the marine environment at that time, Dunkleosteus was at the top of the food chain, and no other creature could compete with it.

The bite force of Dunkleosteus is very strong, reaching 5,300 kilograms, which is 6 times that of the American crocodile. Dunkleosteus lacks real teeth. Instead of teeth, there are a large number of exoskeleton growths on the head of the fish’s mouth. It is as sharp as a sickle and can cut, bite, and grind anything. Dunkleosteus can bite a shark in two with one mouth, and can easily bite rocks into powder.

Dunkleosteus has a terrifying bite force, and even if a shark sees it, it will run away. During the Devonian era, Dunkleosteus was truly the “king of the sea”.
2. “Star animal” plate-footed horseshoe crab

The plate-footed horseshoe crab and the paddle-footed horseshoe crab are similar in appearance and are named because the last pair of appendages are wide and flat like an oar. Horseshoe crabs first appeared in the Ordovician of the Paleozoic Era about 400 million years ago. By the Early Devonian, the number of species and genera of horseshoe crabs reached their peak. Coupled with their unique appearance, they attracted much attention and were Called the “star animal”.

The body of the horseshoe crab is divided into a cephalothorax and an abdomen. The cephalothorax is composed of six body segments. The abdomen has six pairs of appendages. The last pair of appendages is plate-shaped and is used for swimming. With a body length of about 1.5 meters, it is the largest arthropod ever discovered.

Horseshoe crabs live in shallow waters near coastal waters and estuary deltas. They mainly eat carrion, but also small fish, trilobites and other animals in the sand.

Fossils of horseshoe crabs are found in Europe, Asia, North America and other places, and were first discovered in New York State in the United States. Fossils of horseshoe crabs have also been discovered in China. In 2017, Wang Han, a master’s student at the Nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, under the guidance of researcher Wang Bo, accidentally discovered an armored fish fossil in the Silurian strata of Xiushan County, Chongqing. Fossils of a new genus and species of mixed-winged horseshoe crab “Xiushan Dinohorse”. “Xiushan Horseshoe Crab” is a family-level taxon of the order Limulus. Prior to this, scientific researchers had not discovered large predators in the shallow sea areas of the early Silurian period in South China. The discovery of plate-footed horseshoe crab fossils in South China has filled the gap of mixed-winged horseshoe crabs in my country and even the entire Gondwana continent, and is of great significance to the study of the evolution of paleontology.
3. The small-eyed southern panfish with four “wings”

In 1965, a team from the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences collected an early Devonian Lokhokov period (about 419 million years ago) at the Wangjiayuan Quarry in Liokuo Mountain, Qilin District, Qujing City, Yunnan Province. Fossils of the small-eyed Amphitora. This fossil is a cephalon with an incomplete rear part and its impression. The cephalon is roughly pentagonal in shape and about 6 cm in length (excluding the rostrum). The rostral process is short and pointed, about 1/5 of the length of the cephalon. ; The orbital foramen is small and round, close to the middle of the cephalon; the horns are short and triangular in shape; the mid-dorsal foramen is vertically circular; the lateral line system is well preserved, with the posterior supraorbital canal, dorsal communicating canal, lateral transverse canal and dorsal dorsal canal visible; gills There are more than 8 pairs of holes, distributed in the front 2/3 of the head carapace, and the postbranchial area is longer.

The most unique thing about the fish is that there are two laterally extending horns on each side. The ends of these short wing horns are rounded and blunt, and they look like four small “wings” spread out from both sides of the skull. There are huge sea scorpions in the living environment of the small-eyed panfish. Sea scorpions often lurk in shallow waters and prey on armored fish, trilobites and other creatures in the sand. Hydrodynamic analysis shows that the four laterally extending wing angles of the small-eyed Panfish can flexibly control the water flow and have high maneuverability and flexibility, allowing it to escape when encountering sea scorpion prey. The discovery of the fossils of A. microeyes provides important information for studying the origin of fishes in South China.

In the late Devonian period, due to global warming, volcanic eruptions, sea level changes, ocean anoxia, ozone layer collapse and other reasons, most of the strange creatures such as Dunkleosteus, Platypod Horseshoe Crab, and Oculus oculata became extinct. The ecological environment of the ocean has been greatly damaged. In order to prevent marine animals from becoming extinct, humans need to work together to protect the earth and provide a good living environment for marine life.

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