What is a Trilobite



"Three-lobed Creature"


570 million - 230 million years ago

Trilobites are hard-shelled, segmented creatures that lived hundreds of millions of years ago in the Earth's ancient seas.  They are considered to be one of our planet's earliest complex life-forms and are one of the key signature creatures of the Paleozoic Era. 

The name 'TRILOBITE' means 'three lobed" and is derived from the fact these animals had bodies featuring three longitudinal lobes, not lateral (head, body, tail) as is often thought.  The lateral division of three parts is shared by many arthropods, not just trilobites.

Trilobites are the single most diverse group of extinct organisms that ever existed. The smallest known trilobite is just three millimeters long, while the largest type grew to a length of 70 centimeters (over two feet long!).

The most common fossil of trilobites is the mineralized dorsal exoskeleton of the creature.  This is found in partial form from molting (shedding the shell as it grows) or in complete form when the animal was buried and died intact.  The soft parts of the underside are rarely preserved.  Trilobite fossils are collected by locating a fossil-bearing layer in rock and then breaking boulder or splitting rock sheet to reveal the preserved trilobite. Once the fossil is located, the delicate preparation then ensues to remove the surrounding rock above and around the trilobite to expose the fossil.

Trilobites were the first known creature on earth with eyes.

All trilobites have these 3 lobes.

Modern Relatives to Trilobites

Common Characteristics of Trilobites

  1. 1.Compound Eyes

What insects do you know today that has compound eyes?

Answer: flys, bees, ants, wasps

  1. 2.Hard Shell Exoskeleton

Do any of these insects also have a body protection that is a thin shell?

Answer: yes

It is likely then that there is a linkage between trilobites and insect today that share these common characteristics of compound eyes and