7.4" Asaphid Trilobite in Concretion - Pos/Neg
This is a large, 7.4" long Asaphid trilobite in a sandstone concretion from the Kataoua Formation of Morocco. It has a beautiful orange coloration, is very inflated and both halves of the concretion are included. This is one of the nicer examples of these large Asaphids I've seen. The orange coloration is completely natural, caused by the oxidization of iron pyrite which originally replaced the trilobite. There are a few repaired cracks on both halves, but no restoration.
Trilobites were a very diverse group of extinct marine arthropods. They first appeared in the fossil record in the Early Cambrian (521 million years ago) and went extinct during the Permian mass extinction (250 million years ago). They were one of the most successful of the early animals on our planet with over 25k described species, filling nearly every evolutionary niche. Due in large part to a hard exoskeleton (shell), they left a excellent fossil record.