Plumulites and the machaeridian problem

Plumulites richorum sp. nov. is represented by two complete sclerite assemblages from Early Devonian strata of the Humevale Formation in a small quarry northeast of Kinglake West, Victoria. The completeness of these sclerite assemblages necessitates a revision of terminology applied to machaeridians. Moreover, the sclerite assemblages make it necessary to erect a new Family Plumulitidae and allow several deductions about the animal itself, namely: 1, there was a discrete head possibly with soft anterior projections; 2, there was considerable modification of sclerites and their arrangement near the head, indicating possible sexual dimorphism; 3, sclerites were almost certainly not rigidly attached to the soft parts of the animal. The material shows that Plumulites was neither an arthropod nor an echinoderm, but rather a vagile benthic animal probably belonging to the Annelida.