Sourced: Alnif region, Morocco 

Age: Devonian - 419 to 359 million years old

Comes with Cloche 

Spiny trilobites are some of our absolute favorites. Not only do they have all the cool trademarks of a trilobite, but they also have attitude for days. This Philonix trilobite not only has some cool flair in the form of spines that have been cut from the stone matrix, but it also has a certain mystery to it.

Like all prehistoric creatures, we can only guess what some of these features were used for. They are educated guesses, but guesses nonetheless. With this guy, it all comes down to its spines. Some scientists believe they were a form of self-defense. Spines made them harder and less comfortable for predators to grab or swallow. They also helped when trilobites enrolled into a ball, creating a kind of spiky shell that protected the softer parts underneath. Not exactly something anyone would want to eat.

Another theory is stability. In muddy or shifting seafloors, spines could help distribute weight and keep the animal from sinking too easily into sediment.

There’s also a camouflage angle. Spines and ornamentation may have helped break up their outline, making them harder to spot on the seafloor among debris, algae, and uneven textures.

Finally, some spines may have been used for species recognition or sexual selection, where more elaborate forms helped individuals stand out to mates or signal fitness.

In truth, it could be a combination of some or all of these. All we really have to go on are the fossilized remains, seeing as these spiny little creatures have been gone for over 359 million years. It’s fun to ponder these questions, and we often find ourselves doing so as well when we look at it in the display. If you’re looking for an absolute knock-out fossil for your collection, you really can’t do better than this.

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.