Moroccan Trilobites: A Collector's Species Guide

Spiny Devonian trilobite in limestone

In short: most Moroccan trilobites come from Devonian rocks of the Anti-Atlas mountains, about 410 to 390 million years old. The region is famous worldwide for complete, three-dimensional and often spectacularly spined specimens.

What were trilobites?

Trilobites were marine arthropods, distant relatives of today’s insects, crabs and spiders. Their bodies were divided into three lengthwise lobes, which gives them their name. They lived for nearly 300 million years, from the Cambrian until their extinction at the end of the Permian.

Why Morocco?

During the Devonian, what is now southeastern Morocco lay on the margin of the supercontinent Gondwana, covered by shallow seas. The Lower to Middle Devonian rocks of the Anti-Atlas, in areas such as the Tafilalt, the Ma’der and around Alnif, preserve an exceptionally rich trilobite fauna. A 2001 study of just one trilobite subfamily from these rocks recorded 27 taxa, including four new genera.

Popular Moroccan trilobite groups

Walliserops

The most famous: a trilobite with a three-pronged “trident” projecting from its head. Walliserops is known only from the Devonian of Morocco’s Anti-Atlas. Described species include W. trifurcatus, W. hammii and W. lindoei.

Phacops and Drotops

Large, rounded trilobites with big compound eyes made of separate lenses. They are often found complete, sometimes enrolled like a pill bug. Drotops can reach impressive sizes.

Cornuproetus

Small proetid trilobites with a smooth, elegant outline, popular as entry-level specimens.

Koneprusia

Spiny odontopleurid trilobites with long spines along the body, which require skilled preparation to expose.

How Moroccan trilobites are prepared

Trilobites are exposed from the limestone using fine air-powered tools and abrasives. Preparing a spiny species can take many hours or days. Because spines are fragile, some specimens on the market are repaired or partly reconstructed.

What to look for

  • Identification: a genus or species name is better than “Moroccan trilobite.”
  • Completeness: check the head, thorax and tail, and the spines if present.
  • Preparation: look closely at spines and eyes in the photos.
  • Repairs: ask the seller whether any part is repaired or restored.

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