Kingdom Animalia Class Trilobita Superfamily Cyclopygoidea Rank Genus | Phylum Arthropoda Order Asaphida Family Cyclopygidae | |
Circulocrania is an extinct genus from a well-known class of fossil marine arthropods, the trilobites. It lived during the later part of the Arenig stage of the Ordovician Period, approximately 478 to 471 million years ago.
References
Circulocrania Wikipedia(Text) CC BY-SA