Featured in this listing is a trilobite of the phacops genus, Each purchase is for one specimen. Photos show typical examples. Specimens will be chosen at random. These specimens are larger in sized than the tiny enrolled phacops that you typically see sold for less.

Phacops trilobites, or trilobites, are considered to be one of the most interesting kinds of marine animals to people the Earth in the Paleozoic, with well-developed compound eyes containing calc. Trilobites lived during the Devonian period between 418-358 million years ago. They had very special eye structures that were truly unique for those days and they even made it possible for the creatures to survive and be adapted to dim, murky underwater conditions. Each eye is made of clear calcite lenses, which are very effective for focusing the light—one would think how important such an adaptation in that time must have been within the dimly lit waters of the seas.

The body of Phacops trilobites was also uniquely adapted to their lifestyle. Its exoskeleton was in segments and could roll up into a ball, much the same as modern pill bugs. This kind of defense mechanism, referred to as enrollment, served to protect against predators by tucking the soft parts underneath a hard shell. The fossil record does show that these creatures were both resilient and versatile, having survived several mass extinctions before they finally vanished. Their fossils are often preserved in great numbers, not only affording a window into ancient marine ecosystems but also standing testament to the remarkable adaptability and diversity of trilobites as a group.