In ancient times, 540 million years ago, most of the earth was vast oceans, and in the next 20 million years, due to the evolution of life, there was a very famous explosion of life, and the oceans began to have a variety of invertebrate creatures. A series of animals such as arthropods, brachiopods, demodexes, sponges, chordates, etc. that are basically the same as modern animal forms have made a "collective appearance" on the earth, forming a prosperous scene of the simultaneous existence of a variety of phyla. Among them, there is a strange insect, and it is the "typical resident" that appeared in this period, and their tenacious vitality makes this strange insect constantly change over the next 300 million years, and evolve into various forms, this strange insect is the trilobite.
Cambrian Underwater World
The whole body of the trilobite is clearly divided into three parts: head, thorax and tail, the dorsal carapace is hard, and the dorsal carapace is divided into three roughly equal longitudinal segments of the dorsal groove - an axis leaf and two rib lobes, so it is named trilobite. This strange insect has different characteristics, the largest can reach 70 cm, the smallest is only a few millimeters, because of the poor swimming ability, so most of them live in the sediment of the seabed, a few parts are in a floating state. The earliest recorded discovery of the trilobite in China was during the Chongzhen period of the Ming Dynasty, a person named Zhang Huadong found a kind of "monster" buried in stone in Dawenkou, Tai'an, Shandong, whose appearance resembles the spread of bat wings, so he named it "Bat Stone", and later used this stone to make a yantai, named "Duofu Yan", also known as "Yan Shi Yan", which has the meaning of Fu Rui and peace.
Bat Stone
Trilobites belong to the trilobite of the arthropod Phylum Trilobites, which are divided into 10 orders, including bulbophyllum, Lederliki, Bulbophyllum, Bulbophyllum, Mirror-eyed Worm, Ribostomy, Ctenophora, Sickleworm, Plesiosaur, and Ribocarpus. In total, there are more than 1500 genera, more than 10,000 species, and about 500 genera have been found in China. Among them, "bat stone" belongs to the order Officiae, and is named Pu's batworm. The Cambrian trilobites were extremely prosperous, with early insects having large eye leaves, many thorax segments, and small tails, and in the middle and late period, the tail began to evolve and enlarge, and grew tail spines. The more typical early trilobites are called Chinese Lederlikiella, the head saddle is tapered or columnar, the head saddle is larger, there are 3 to 4 pairs of saddle grooves, the eye lobes are like a crescent moon, the thoracic segment has 15 segments, and the tail is small. The typical trilobite in the middle and late period is a batworm, which looks more like a bat or swallow because of the development of tail spines.
Lederliki worm
Entering the Ordovician period of 480 to 440 million years, the sea and land pattern basically inherited the characteristics of the Cambrian Period, the sea invasion reached its peak, the sea water receded in the middle and late period, the north China continent gradually expanded, and small land uplifts also appeared in the southwest region. Trilobites in this period have been quite different from the Cambrian period, the head and tail have evolved to become larger, but the body is gradually reduced, and the saddle ditch has disappeared. Some also have snail-like eyes, some have several horns on their bodies, and swimmer trilobites with a wide field of vision have appeared. Because there were few natural enemies in the ocean at that time, the Ordovician became the "era of great trilobite prosperity". The more famous one is called the Three Tumor Worms, which are named because of the three bulges on the head. There is also a large trilobite in China, called Xiangxi worm, with a body length of 10 to 25 cm, an overall oval shape, a semi-circular head, and a backward curve to the left and right ends, with cheek spines, and a pair of small lateral spines on the posterior edge of the tail.
Nanjing three-tumor worm
Xiangxi worm
The time came to the Silurian, 440 to 410 million years, after escaping the extinction event of the late Ordovician, the trilobite population went into decline, and fewer and fewer species remained. The more common one in China is the crown worm. Crown worm has a series of small protruding tumors at the edge of the head, the head is triangular, with three hemispherical protrusions arranged in the shape of a "pin" glyph, hence the name crown worm. The main production is in southern Sichuan, northern Qianbei, western Hubei, and southern Anhui is also produced. On the first floor of the Museum of Ancient Humans and The Ancient Spine in Beijing, there is a game of fossil fighting for children, most of which is this crown worm.
Crown worms
By the Late Paleozoic Devonian, the Earth had once again experienced a time of mass extinction, and this time the impact on trilobites was profound, lasting into the Carboniferous Period, where only a few species of trilobites remained. In the Permian, only one family of Fischeraceae remained, and in the late period, the third mass extinction occurred, this time the most destructive mass extinction event. The global climate has undergone great changes, earthquakes and volcanic eruptions, a series of natural disasters, the ecological environment of the ocean has caused unprecedented damage and reconstruction, the survival of marine animals has become very difficult, and this time the trilobite is completely extinct, and the strange insect has come to a perfect end.