Gerastos is a genus of extinct marine arthropods belonging to the class Trilobita, which thrived during the Paleozoic era. Trilobites are among the earliest known groups of arthropods, with a fossil record spanning over 270 million years, from the Cambrian to the Permian period. Gerastos, in particular, is known from the Devonian period, approximately 419 to 359 million years ago.

They are related to the modern-day horseshoe crab. These creatures had a hard exoskeleton that was conspicuously segmented, enabling them to roll up just like a modern roly-poly. Gerastos, like many trilobites, possessed compound eyes made up of numerous small lenses—similar to those of modern arthropods like insects and crustaceans. These eyes were located on the cephalon and provided a wide field of vision, crucial for detecting predators and navigating their environment.

Gerastos trilobites lived in marine environments, ranging from shallow coastal waters to deeper offshore settings. Their fossil distribution suggests they were benthic organisms, living on or near the seafloor. Fossils have been found in various parts of the world, including Europe, North Africa, and North America. This wide geographic spread indicates that they were a successful and adaptable genus during the Devonian period.

Like all trilobites, Gerastos went extinct by the end of the Permian period, around 252 million years ago, during the Permian-Triassic extinction event. This event was the most severe extinction in Earth’s history, wiping out approximately 90% of marine species. The exact cause is still debated, but it’s commonly attributed to a combination of volcanic activity, climate change, and ocean anoxia.

You will receive a high-quality specimen, but not the exact one pictured here.