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Approximately 521-252 million years old

Everything about trilobites is cool, and we could spend hours going on and on about them. We don’t think you want to read a book, so we’ll just hit the highlights.

A Psychopyge trilobite is a genus that lived during the Paleozoic Era (about 521–252 million years ago). Sometimes called the "Swordnose Trilobite" (for obvious reasons), it’s distinct and definitely stands out from its kin. Its “sword” is technically part of the rostral, or anterior projection of the exoskeleton, which in this species is elongated and tapered. Like all prehistoric and extinct creatures, scientists don’t know exactly what it was used for, but most think the swordnose helped Psychopyge plow through sediment on the sea floor to find food. It may have also deterred predators or protected the head while moving through tight spaces. Who would want to mess with a guy that has a sword on his head? Seems pretty effective to us.

About trilobites in general:

These ancient marine arthropods are especially famous for their large, highly detailed compound eyes, some of the most impressive ever found in trilobites. Fun fact: trilobites are the only known animals to have eyes made with calcite lenses. Yes, like the crystal calcite. How cool is that?

Their compound eyes were built from tiny lenses made of calcite, a transparent form of calcium carbonate. Each lens sat on top of a photoreceptor cell beneath the exoskeleton. Because trilobite shells were already made largely of calcite, their eye lenses were essentially part of the mineralized exoskeleton.

These creatures thrived on Earth roughly 419 to 359 million years ago, long before the dinosaurs. There’s a gap of about 20 million years between the extinction of trilobites and the appearance of the first dinosaurs. Trilobites were everywhere until the Permian-Triassic extinction event, ominously known as “The Great Dying.” No one knows exactly what happened, but scientists believe a combination of massive volcanic eruptions, extreme climate change, ocean acidification, and low oxygen levels devastated marine ecosystems during this mass extinction.

Considering the scale of that event, you probably won’t be shocked to hear that trilobites have no direct living descendants today. Their closest living relatives are thought to be arthropods, the group that includes horseshoe crabs, spiders, and crustaceans. Sadly, we probably won’t ever see a resurgence of calcite-eyed sea bugs, but nature has a way of surprising even the most astute among us. Guess we’ll have to wait a few million years to find out.