Trilobites are the most representative ancient animals that appeared in the Cambrian period 560 million years ago, which is a kind of arthropod, the whole body 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 - an axis leaf and two rib leaves, so it is called trilobite.
Trilobite fossils
Trilobites reached their peak 500 million to 430 million years ago, and by the Permian period 240 million years ago, they had survived on the earth for more than 320 million years, which showed that this is a type of organism with strong vitality. Over the course of time, they evolved into a wide variety of species, some up to 70 centimeters long, some only 2 millimeters long
In animal taxonomy , trilobites belong to the phylum arthropods , trilobites. They lived in ancient oceans, occurring mainly in the Cambrian period and reaching their apex by the late Cambrian period. Since then, trilobites have gone from the peak of their peak to decline, and continued to extinction at the end of the Permian, without entering the Mesozoic Era. Trilobites have grown over the long geological course of more than 300 million years throughout the Paleozoic Era, producing numerous taxa and huge numbers, and trilobites can be divided into 10 orders: Bulbophyllum, Lederliki, Rod-headed Worm, Fold-cheek worm, Mirror-eye Worm, Ribopod, Ctenophora, Sickleworm, Lycopoda, and Ribophyllum. [2] In total, there are more than 1,500 genera and more than 10,000 species, of which about 500 genera are found in China.