Trilobites

The trilobites are a diverse class of widespread arthropods from the Terrenuevian-Lopingian of the entire world. They, as a whole, were named by Johann Ernst Immanuel Walch in 1771. They were one of the most successful animals to exist (roaming the seas for about 270 million years), and have a thorax that can be split into 3 lobes, thus the meaning of their name, "three-lobed".

## Physiology

Trilobites were unique arthropods. They had a body consisting of three body parts (the cephalon, the thorax, and the pygidium), lots of pairs of walking legs, a thorax consisting of 3 lobes, large calcite eyes (located on the cephalon), long antenna (also located on the cephalon), and in some cases, spines. Their bodies would have been covered in a hard, chitinous exoskeleton.

## Diet

Trilobites were carnivores, either living as predators, scavengers, or filter feeders. In predatory trilobites, the first pair of walking legs were modified into claws connected to small spines, which were used to tear prey items into pieces and, in some cases, crush their hard shells.

## Other Attributes

### Location

China, Korea, Pakistan, Nepal, Iran, Spain, Siberia, Antarctica, Australia

### Diet

Carnivore

Redlichia is a redlichiid redlichiid trilobite from the Cambrian Series 2 of China, Korea, Pakistan, Nepal, Iran, Spain, Siberia, Antarctica, and Australia. It was officially named in 1902 by Maurice Cossmann. It was one of the largest trilobites, only beaten in size by the later Isotelus. It was a predator, preying on smaller hard-shelled arthropods as well as other small invertebrates.

## Other Attributes

### Location

Canada, United States of America, Greenland, Kazakhstan, Russia

### Diet

Carnivore

Olenoides is a dorypygid corynexochid trilobite from the Cambrian Series 3 of Canada, the United States of America, Greenland, Kazakhstan, and Russia. It was named in 1877 by Fielding Bradford Meek. It was the most common trilobite in Cambrian Canada, and by extension, one of the most common arthropods (only beaten by Waptia and Marrella). It was a predator, preying on small invertebrates.

## Other Attributes

### Diet

Carnivore

Cheirurus is a cheirurid phacopid trilobite from the Furongian-Middle Devonian of the entire world. It was named in 1854 by Nils Peter Angelin. It was a very unique trilobite, as it had spines protruding from its cephalon and pygidium to help protect it from predators like eurypterids, lobe-finned fish, and placoderms. It was a predator, preying on small invertebrates.

## Other Attributes

### Diet

Detritivore

Isotelus is an asaphid asaphid trilobite from the Middle-Late Ordovician of the United States of America and Canada. It was named in 1824 by James Ellsworth De Kay. It was the biggest trilobite to ever live; however, it would still have been prey to predators like Cameroceras. It was a detritivore.

## Other Attributes

### Diet

Carnivore

Phacops is a phacopid phacopid trilobite from the Early-Late Devonian of the entire world. It was officially named in 1839 by Hermann Friedrich Emmrich. It had complemented the trilobite defense mechanism of rolling up into a ball in a woodlouse-esque manner, mainly to protect itself from predators. It was a detritivore.

## In popular culture

Due to documentaries and books focusing on prehistoric animals, trilobites have become the most popular prehistoric arthropods to have ever existed. Since then, they have been featured in major pieces of media like *Fantasia* and *Chased by Sea Monsters*. So far, their biggest public appearance was in the first episode of the 2005 documentary, *Walking with Monsters*, where the Asian trilobite genus, Redlichia, was shown as a common animal in Cambrian China, as well as prey for the Earth's first superpredator, Anomalocaris.