3.4" Lower Cambrian Trilobite (Neltneria) With Pos/Neg - Issafen
This is a really nice, 3.4" long example of Neltneria termieri from Issafen Formation. This is one of the more uncommon species in the formation. It was essentially a perfect split and both the positive and negative impression are included.
In the past few years, deposits near Issafen, Morocco have begun yielding a new assemblage of Early Cambrian trilobites. This fauna is very diverse and consists mainly of ellipsocephalids, chengkouiids, gigantopygids, holmiids, neltneriids, saukiandids, and the latest fallotaspids. The shale when freshly split is a greenish to slightly yellow color but weathers to a light grey.
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.