Magelonidae Cunningham & Ramage, 1888 (Annelida, Polychaeta)—Worldwide Identification Keys and the Re-Establishment of Maea Johnston, 1865

Shovel head worms (Annelida: Magelonidae) have long presented challenges to polychaete systematists due to their unique morphology and relative uniformity. This has been compounded by a lack of taxonomic work across key biogeographic regions. However, over the past few decades, a series of studies has progressively addressed these issues, refining our understanding of magelonid taxonomy and making taxonomic revisions of several regions. Whilst a standardised framework for morphological characters across the family has been produced, a worldwide review of taxonomic knowledge has been warranted. The information is herein presented alongside the first worldwide identification key in over 50 years. The much-needed key is presented in two formats: a dichotomous key divided by marine realms, and a pictorial key based on putative morphological groups. The key is additionally supplemented by the provision of an interactive map providing type locality data and links to taxonomic works. The pictorial key provides additional support for the unique terminology historically applied to the group. The genus Maea Johnston, 1865 is herein re-established for fifteen species possessing long rounded prostomia without horns, but possessing mucronate chaetae of the ninth chaetiger, and lateral abdominal pouches.