Abstract
The taxonomically challenging cyclostome bryozoan family Horneridae is abundant and diverse in the waters around Aotearoa New Zealand. Using a combination of molecular and morphological approaches, we developed diagnostic characters for species of hornerids, describing 11 species (7 of which are new) in three genera (one of which is new and one reinstated) from the seafloor around southern New Zealand between Cook Strait at ∼42°S and the subantarctic islands at ∼55°S. Gracilohornera gen. nov. comprises five small, gracile species: the type species G. currieae, in addition to G. granolineata sp. nov., G. taitonga sp. nov., G. retrosa sp. nov., and G. tumida sp. nov. The reticulate genus Retihornera is revived and includes R. squamosa and R. foliacea, which are compared with the type species R. corbicula. In the genus Hornera, we describe the pinnate and palmate branching species H. girvanae sp. nov., H. polaris sp. nov., and H. querciformis sp. nov., comparing them with Hornera robusta. In contrast to other regions, hornerid cyclostomes in Aotearoa New Zealand have flourished and diversified; indeed, many more hornerid species might await discovery in New Zealand waters.