Odd shrimp is a genus of strange shrimp in protochelopods of Arthropoda.[9]The strange shrimp is one of the typical animals during the "Cambrian life explosion" period, which can grow to more than two meters;The eyes of the strange shrimp are about the same size as the table tennis ball. The mouth is 25cm in diameter, like a big bowl. The forelimbs are large and developed, and there are fan tails and tail forks.[10]The strange shrimp is also called fearsome shrimp.[11]
The rare shrimps are mainly distributed in Chengjiang fauna in Yunnan, China. They were first found in western Canada. The Burgess shale fauna in the middle Cambrian of the Rocky Mountains has been found in Cambrian strata in many parts of the world.[9]The strange shrimp has sharp teeth and sharp mouth, and can also "net" to catch food.Scientists found the remains of small shelled animals in the fecal fossils of strange shrimp, indicating that it was a carnivore in the Cambrian ocean.[11]
The strange shrimp was once found in the Early Devonian strata, so it is inferred that its extinction time will not be earlier than 400 million years ago. As a species without natural enemies in the ocean at that time, why the strange shrimp became extinct is still a mystery.[12]
Material: A basically complete fossil of the front appendage of a strange shrimp, preserved both positively and negatively.Preserved in purplish red shale, the fossils are black due to infection.
Early marine large carnivores - strange shrimp
Description: The preservation length of the specimen is about 2.3cm. A total of 12 limb segments have been preserved. The base is missing and the end is incomplete.The front appendage is straight, and the middle and rear appendages are slightly curved.The length of each limb segment gradually decreases backward.Each limb segment corresponds to a pair of ventral spines. The basal ventral spines are not found. The ventral spines are spaced in size. The middle ventral spines are longer, and the ends of the ventral spines are not very sharp. No obvious ventral spines are found.The included angle between abdominal spine and limb segment is 100.It gradually transits from left to right to 80.about.It can be seen that there is a clear end spike, medium in size, with a sharp end, and another end spike may be preserved.Two short and strong pyramidal dorsal spines can be seen on the back of the penultimate segment.[2]
Profile features
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The most ferocious predator in the sea 530 million years ago was the strange shrimp.It has a pair of huge eyes with handles, a pair of segmented giant forelimbs for fast hunting, a beautiful big tail fan and a pair of long tail forks.Although it is not good at walking, it can swim fast.The huge mouth with a diameter of 25 cm can prey on any large creature at that timeCircular arrangementThe exodontia of these animals, which are protected by mineralized exodontia, pose a major threat.This is a carnivore with strong attack ability. Its maximum size can reach more than 2 meters, while most other animals were only a few millimeters to a few centimeters on average at that time.[3]
Strange Shrimp Discovery Site
Strange shrimp has another alias: fear shrimp.The reason is that it is really scary.The head of the strange shrimp has a pair of big pincers. Its eyes are as big as a table tennis ball. The most frightening thing is its mouth, which looks like a big bowl, with sharp teeth distributed like gears.[4]
Anomalocaridids are a kind of huge and peculiar fossil arthropods with large and fine compound eyes, specialized predation appendages, mouth cones and swimming paddle shaped limbs, which show a high degree of adaptation to predation behavior.Because the mouth cone is radial, the strange shrimp is also called Radiodonta.The maximum body length of strange shrimp can reach 2 meters, which is considered as PhanerozoicMarine ecosystemThe earliest top predator in the "Cambrian Explosion" is also one of the most representative star animals.[5]
The body of the strange shrimp is composed of non skeletonized soft bodies, which can only be preserved in the specially buried soft body fossil library. Most of the strange shrimp fossils are discrete body parts, and have been named as different species.Complete strange shrimp fossils are very rare, first found inCanadaMiddle CambrianBurgess shale biotaSince thenChengjiang biota Fezouata biota of the Early Ordovician in Morocco and Hunsr ü ck slate biota of the Early Devonian in Germany.Up to now, there are 13 genera and 21 species of strange shrimp fossils reported, which are produced in 25 soft body specific buried fossil banks in the world from the early Cambrian to the early Devonian, about 120 million years ago.[5]
The eyes of the strange shrimp are about the same size as the table tennis ball. The mouth is 25cm in diameter, like a big bowl. The forelimbs are large and developed, and there are fan tails and tail forks.
Its typical feature is a three part head shell complex located in the head.The head shell complex is hinged by a middle plate at the back and a pair of side plates at both sides.The middle plate is symmetrical on both sides, and the side plate itself is asymmetrical.
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Herd shrimp
Herd shrimp
Survival habit
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The teeth are sharp and the mouth is sharp, and they can "net" to catch food
Strange shrimp is a big stomach king. Even the excrement is about the size of a bowl.Paleontologists once found the broken shells of trilobites in the excrement of strange shrimp. The trilobites are extremely hard, and the strange shrimp can bite the trilobite shells.
Strange shrimp tooth apparatus
Huang Diying and his colleagues found that the claws of the strange shrimp on the fossils had many reticular claws, and some had very long spines.They speculated that these thorns formed a net, and all animals passing by could not escape from the net, and eventually became food for strange shrimp.
"The most primitive method was to use big pincers directly. Later, 'net pockets' evolved.' Net pockets' hold more food and are fast. These two kinds of predation methods coexist together." Huang Diying said, which indirectly shows that even marine overlords have fierce competition for survival, and they need to evolve more advanced predation methods to meet their survival needs.[4]
Research findings
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Although the strange shrimp is also called "shrimp", it has no kinship with our modern shrimp.The strange shrimp is a big man more than 500 million years ago. It is more than two meters long. Maybe it is too big. Most of the preserved fossils are fragments, which can be fully seen after combination.[4]
Rare Shrimp Fossils
Scientists found the remains of small shelled animals in the fecal fossils of strange shrimp, which indicates that it isCambrianThe carnivores in the sea are the rulers of the sea world and the ultimate consumers of food.The discovery of strange shrimp shows that there was a complete food chain in the ocean at that time.The new research found that the prey limbs of the strange shrimp can be bent, and the legs can walk on the seabed, but itsAppendageThere is no differentiation, and there is no joint between the nodes.
The recipe of strange shrimp may include othersCarnivore。With such a large body, such a large mouth and such a pair of large capture organs, it can prey on the largest living creature at that time, and will never only eat the food atfood chainThe creature at the lowest position, because its claws are too thick, it is not so easy to grasp small food.
No one would think that strange shrimps were not the "fittest" in the ocean at that time.It can be called the "Big Mac" in the ocean. At the top of the food chain, it can easily hunt enough food, but no other creatures can threaten its survival.However, like the dinosaurs that once dominated the land, the strange shrimp has long been extinct.[3]
The two sides of the body of the strange shrimp are equipped with split wings, which are shaped like modern shrimp. The two tentacles are covered with barbs, and the mouth is composed of crustaceans;In the past, paleontologists generally believed that it was perfectly reasonable for these structures of strange shrimp to hunt and munch trilobites.
However, in Denver, Colorado, USA,American Geological SocietyAn annual seminar was held, in which the 3D model of the mouth of the strange shrimp was displayed, showing that this ancient carnivore that everyone imagined might only eat soft paste food.
Research shows that strange shrimps mainly eat soft things, such as insects in the mud, soft microorganisms floating in the water, etc.
The strange shrimp was first found in Canada. At that time, only the fossil of one front claw was found, which was mistaken for the tail of the shrimp.The scientist also imagined a shrimp head, which was named as strange shrimp because it was not a shrimp.In 1994, Chinese scientists found a complete fossil of strange shrimp in Maotianshan Mountain, correcting the previous mistake. The so-called "tail" is actually its claws.
In 1992, when a highway was built on the north slope of Maotian Mountain, the bulldozer pushed out a huge section, giving the chance to discover the strange shrimp fossils.In the first specimen, only the end of the anterior appendage was exposed at the beginning of discovery.Driven by curiosity, Zhou Guiqin of the Nanjing Institute of Geology and Palaeontology repaired it on the spot in the field.When a complete pair of front appendages and head were exposed, she could not help shouting excitedly.[3]
The appearance of the first strange shrimp specimen leads to the appearance of the third complete strange shrimp.In fact, this "third piece" of strange shrimp fossils has been collected by Nangu since 1990Zhu MaoyanIt was collected, but its strange shape was confusing at the beginning, so it was left out in the tray in the office for nearly 2 years.With the restoration of the specimen, a complete image of a fierce hunter appeared in front of people.[6]
Visual characteristics
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The ugly strange shrimp was an undisputed terrorist in the sea more than 500 million years ago.The length of the strange shrimp can reach 2 meters. By fanning the leaves on both sides of the body, it moved horizontally in waves in the early Cambrian sea water.Its mouth is like a disc, which is composed of 32 overlapping suction cups. It can approach prey, swallow and crush them.However, its mouth has never been completely closed.In front of its mouth, there are two powerful pliers with great grasping power. There are many barbed spikes on the pliers, which may be used to catch and swallow prey.
Anomalocaris
This monster has led to many unsolved mysteries. For example, the recipe of strange shrimp is still unknown.Some people believe that this creature feeds on trilobites, and the evidence includesTrilobite fossilIt is generally damaged like bite marks.But recently, some experts have questioned this view.First of all, no fossils of strange shrimp feces (and no residues in the stomach) have been confirmed to have signs of indigestible trilobite bones.The mouth of the strange shrimp is too weak to crush the trilobite's shell.In view of the bite marks on the trilobite fossils, some people suggested that the strange shrimp might want to chew or swallow the trilobite, but instead of swallowing them, it vomited them out.The main food of the strange shrimp may be soft microorganisms.
Strangely, the eyes of the strange shrimp grow on the meat handle on the side of the head.Through the analysis of fossils from the Canga Beast Island, South Australia, scientists found that the strange shrimp has compound eyes similar to modern insects, the only difference is that each eye of the strange shrimp has more lenses (according to the articles in Nature by Patterson and other scientists, each eye of the strange shrimp has up to 16000 hexagonal lenses).This unusual eye (probably needs a quite advanced brain) provides a very sharp vision for the strange shrimp.
Patterson said: "Only a few modern arthropods have such complex eyes." For example, each eye of a fly has only 3000 lenses.The only thing that can be compared with the strange shrimp is some predatory dragonflies, which have as many as 28000 lenses per eye.
The strange shrimp is one of the many strange creatures that appeared during the Cambrian explosion of life (about 530 million years ago), but people have never found ancient creatures representing their ancestral forms.What is more surprising is that there is no evidence that Cambrian creatures are simpler than living creatures today, such as fewer cell types or more primitive eye structures;On the contrary, the animal morphology of the Cambrian era was complex and exquisite.Scientists have not been able to give a reasonable explanation for this.[7]
Cambrian overlord
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In the Cambrian period, there was an animal that was a thousand times larger than other animals, that was "strange shrimp".In 1886, Richard McConnell of the Canadian Geological Research Institute found a fossil of an animal's tentacle near the Burgess Formation.According to this fossil, he thinks it is a kind of shrimp fossil.So they named it "strange shrimp" in Greek according to the meaning of "strange shrimp".
Since then, Wokoot and others have found fossils of the mouth and part of the body of the strange shrimp, but they mistook them for jellyfish and sea cucumber fossils.It was not until Dr. Whittington and others discovered the fossils of all parts of the body of the strange shrimp in 1981 that they finally recovered the shape of the strange shrimp we see today.
It is now clear that strange shrimps have sharp mouthparts and are predators. They feed on other animals.When other Cambrian animals are only a few centimeters to ten centimeters in size (except some sponges), the strange shrimp with a body length of more than 60-200 centimeters appears extremely huge, and is the overlord at the top of the food chain of the Cambrian ecosystem.It can be said that the strange shrimp was the master of all animals on the earth at that time.[8]
The Mystery of Extinction
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More than 440 million years ago, the strange shrimp died out mysteriously.Why did it disappear from the earth forever?
It may be starved to death due to the loss of species advantage. Like dinosaurs, strange shrimp did not escape the fate of extinction.Huang Diying said that the latest discovery of strange shrimp was more than 440 million years ago, and the race had been alive for less than 100 million years.How did the strange shrimp become extinct?Huang Diying said that it was still a mystery.However, he speculated, "Later, the size of marine life became larger and larger, some even larger than the odd shrimp. The odd shrimp has no such advantage, there is not enough food to meet its survival needs, and it may be starved to death."[4]
Two new varieties
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The first discovery of strange shrimp is in Yunnan, ChinaChengjiang Fauna About 530 million years ago, among Chengjiang fauna, strange shrimp was the top predator of the food chain at that time.Scientists speculated that the largest strange shrimp 530 million years ago could be more than two meters long, while most other animals were only a few millimeters to a few centimeters on average at that time. It was too big, and at that time, it was definitely the rightful ocean overlord.
The strange shrimp fossils collected by Huang Diying were millions of years later than the age of Chengjiang fauna, and lived about 520 million years ago.They put the fossils under a microscope and studied them carefully, and found two new species of strange shrimp.Why are they new varieties?Huang Diying said that the new variety of strange shrimp has more knots on its claws and better elasticity;At the same time, the barbs on the jaw are also different.
More than 10 kinds of strange shrimp have been found all over the world. It is believed that with further research by scientists, more types of strange shrimp will be found.[4]
Unsolved mystery
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530 million years ago,ChengjiangIt is a blue sea, where many animal ancestors live.However, due to geological movement, marine organisms became fossils after hundreds of millions of years of burial.Maotian Mountainanimal fossilBelonging to the Early Cambrian in eastern YunnanfaunaIt features the rare preservation of mollusc fossils and is a world-famous fossil treasure house.
Mr. Zihou Xianguang was in Chengjiang in 1984Maotian MountainSince the first discovery, more than 120 kinds of animal fossils have been identified, belonging toSponge animal、coelenterateArthropodsEchinodermaAnd more than 10 animal phyla and some strange groups with unknown classification position.Chengjiang Fossil Site It fully shows the diversity of early Cambrian organisms, and represents the true features of marine organisms more than 500 million years ago.
Micronet is also calledNine eyed wormIt is named because it has nine pairs of eyes.The cap Tianshan worm belongs to hemichords.jellyfishIt is a transparent echinococcus.Especially chordatesYunnanozoon It is of great significance to study chordates.The strange shrimp, known as the "overlord" in the water, is very similar to the common shrimp in morphological characteristics, but it seems to lack a head, which is strange, so it is called strange shrimp.Until 1979, British biologistsHilgusA relatively complete fossil was found in the shale specimen before the discovery of "strange shrimp".It turned out to be a huge prehead appendage with a circular mouthpiece, which solved the mystery of a century.The strange shrimp is the largest and most ferocious giant carnivore in the sea more than 500 million years ago. It is called the "Big Mac" in the sea.The largest strange shrimp can be more than 2 meters long, while the individuals of other kinds of animals in the sea were only a few millimeters to a few centimeters at that time.There is a pair of multi segmented, spiny, powerful front appendages used to catch food in front of the head, and a pair of giant eyes with handles in front of the head;There is a circular mouthpiece composed of 32 outer lip poles in the center below the head. The maximum diameter of the mouth can reach 25 cm. It can swallow various giant animals, which also poses a serious threat to animals with external armor protection.
The body of the strange shrimp is streamlined, with flat back and abdomen. The body is segmented but without dorsal armor. There are eleven pairs of broad paddle shaped leaves with vein supporting structure on both sides of the body. The tail sector is composed of three pairs of flaky tail leaves, and a pair of slender tail spines protrude backward from the back center of the tail end.The special body structure of the strange shrimp determines that it is good at swimming and better than hunting. It is an invincible family in the Cambrian ocean.
Cause of disappearance
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1. The new species will eliminate the strange shrimp.
Anomalocaris
2. The deterioration of the environment has threatened the survival of the strange shrimp.
3. The invasion of alien species reduces the food source of strange shrimp.
4. Poor intelligence, unable to adapt to the living environment.
