Protaspid and early meraspid growth stages of the eodiscoid trilobite Pagetia ocellata Jell, and their implications for classification

摘要: During recent investigations of the Middle Cambrian phosphate deposits south Duchess in Burke River Structural Belt, Georgina Basin, western Queensland, large numbers early growth stages trilobites have been recovered by acid etching samples from Monastery Creek Phosphorite Member Beetle Formation. Among these a late protaspid stage is recognised as belonging to Pagetia ocellata Jell 1970, described earlier same formation. The morphogenesis this and earliest meraspid are described, their development compared that an associated agnostoid referred Peronopsis. differences between eodiscoid reviewed light much recently published information. A taxonomic separation at least ordinal magnitude advocated. If miomeran arthropods related polymeroid trilobites, then eodiscoids closer two groups.