What kind of creature is a trilobite? What kind of animal is the trilobite

Trilobites appeared in the Cambrian period hundreds of millions of years agoThe most representative of ancient animalsYesA species of arthropods,The whole body is clearly divided into three parts: head, thorax, and tail, and the dorsal carapace is hard, and the dorsal carapace is divided into three roughly equal pieces longitudinally - one axial lobe and two rib lobes, hence the name trilobite.

Trilobites reached their peak 500 million years ago, and were completely extinct in the Permian period 100 million years ago, and survived on the earth for more than 100 million years. Over time, they have evolved into a wide variety of species, some up to 70 centimeters long and some as small as 2 millimeters.

In animal taxonomy, trilobites belong to the phylum Arthropod and Trilobite Deficients.

Trilobite is the most representative ancient animal that appeared in the Cambrian period hundreds of millions of years ago, is a kind of arthropod, the whole body is obviously divided into three parts: head, thorax and tail, the dorsal carapace is hard, the dorsal carapace is two dorsal grooves longitudinally divided into roughly equal buried three pieces, an axial lobe and two rib lobes, so it is called trilobite.

Trilobites can be divided into 10 orders: Globular Zodia, Ledliki, Shrug-headed Insects, Cheek-cheeked Insects, Specular Insects, Schizozoides, Ctenophorids, Fucythes, Calenders and Dentates, with a total of more than 1,500 genera and more than 10,000 species.

Hello dear kiss, very high Sui Changxing for you to answer, trilobites belong to the sedan chair what kind of animal trilobites belong to invertebrates, it is a kind of arthropod that has been extinct, the whole body is divided into three parts: head, thorax and tail, the back carapace is hard, and it is divided into three pieces by two longitudinal deep grooves, so it is called a trilobite. <>

Trilobite is the Cambrian period before the first hundred million years of the cavity is the most representative of the ancient animal of Qinzhen, is a kind of arthropod, the whole body is clearly divided into three parts: head, thorax and tail, the dorsal carapace is hard, the dorsal carapace is two dorsal grooves longitudinally divided into roughly equal three pieces - an axial lobe and two rib lobes, so it is called trilobite Wu this.

Trilobites are arthropods that spread all over the world in the Cambrian period, named because their bodies are divided into three parts by two "vertical lines", which are also the most prominent physical characteristics of trilobites.

The "three-lobed" body of a trilobite.

Trilobites are the most representative ancient animals, they first appeared in the Precambrian period 100 million years ago, and did not become completely extinct until the end of the Permian period 100 million years ago, and survived on the earth for more than 100 million years. Over such a long period of time, trilobites have evolved quite a few species. Different types have different shapes.

Scientists divide the known trilobites into eight orders.

There are all kinds of trilobites and different sizes, and not all of them are the size of the insect you remember. At present, there are tens of thousands of trilobite fossils found in the world, the largest body length is nearly 1 meter, and the smallest is only 2 millimeters. With their super adaptability, they are widely distributed in the world's oceans, and it can be said that in the Cambrian period, there were oceans and trilobites.

The largest trilobite is 72 centimeters.

Trilobites are not powerful predators, but their widespread and long-lasting survival is inseparable from their excellent defense strategies. The difference is that the shell of the trilobite is quite hard, and the general teeth can't help it, and in the later stage, many trilobites have a lot of spikes on their shells, and after curling up, the predators have nowhere to go. Therefore, the curled up "thorn ball" may also be a trilobite!

Curled up trilobites.

The above content refers to Milley's children's book "A Brief History of Life".

From the back, trilobites are ovate or oval, and adults are 3 10 cm long and 1 3 cm wide. Compact 6 mm or less. Structurally, it can be divided into three parts: head carapace, cuirass and tail carapace.

The trilobite body is covered with a shell, the hard shell is the dorsal shell and the ventral edge extending to the ventral surface. The arthropods of the ventral surface are chitin, and the rest of the body is covered by a soft membrane. In general, the fossils of trilobites collected are dorsal shells.

The middle part of the dorsal shell of the trilobite is called the axial or central axis, and the left and right sides are called the ribs or ribs. Trilobite shell surface is smooth. There may be traps, tumors, spots, radial lines, concentric lines, short spines, etc.

The head is mostly divided into three lobes by two dorsal grooves, with the middle bulge being the saddle and neck ring[2], the two sides are buccal, and the eyes are located at the buccal. The cheeks are crossed by the face line, the medial part between the two face lines is collectively called the cranium, and the two sides are called the movable cheeks or free cheeks. The thorax is composed of several thoracic segments, which vary in shape, and the adult worm has 2 40 segments.

The middle part is the central axis, and the two sides are called the ribs. Each costal joint has a costal sulcus, and the two costal nodes are intercostal sulcus. The tail is formed by the fusion of several segments, ranging from 1 to 30 segments.

The shape is generally semicircular, but it varies greatly and can be divided into one central axis and two ribs. Costal segments, with costal and intercostal sulcus. The ribs may be marginal, and there are often marginal spines on the margins.

The ancestors of trilobites may have been arthropod-like animals, such as the Sprig worm or other trilobite-like animals from the Ediacaran period of the cryptozoic epoch. Early trilobites have many similarities with Burgess Shale and other Cambrian arthropod fossils. Thus, trilobites and other arthropods may have a common ancestor before the junction of the Ediacaran and Cambrian periods.

Trilobites developed rapidly, reaching their high point of reproduction in the late Cambrian period. In order to adapt to different living environments, morphological evolution is varied. Some have three parts of the head, thorax and tail of equal size, the shell is flat, and the head and tail lack obvious ornamentation, such as the big-headed insect (bumastus).

Some heads are broad and large, with a flat perimeter surrounded by a flat perimeter and neatly arranged with tumors such as crypolithus; In order to avoid injury, some are decorated with long needle punctures on the chest and tail, such as lichas; Some shells can also be curled into globules, such as CalymeneAnother group of arthropods, mesomorphs, also appeared in the Ordovician. , 3, Trilobites developed rapidly, reaching their reproductive highs in the late Cambrian era.

In order to adapt to different living environments, the morphological evolution is diverse. Trilobite fossils.

Some have three parts of equal size, the thorax and the tail, the shell is gently flattened, and the head and tail lack obvious ornamentation, such as the head (bumastus): some heads are wide and large, and the front edge is surrounded by a wide circumference of the world, and there are neat nodules arranged on it, such as crypolithus; In order to avoid injury, some are decorated with long needle punctures on the chest and tail, such as lichas; Some of the shells are okay. 2,