Morphological and taxonomic diversity of the bryozoan genus Chaperia (Cheilostomata: Chaperiidae) in the Aotearoa New Zealand EEZ and on the southern Norfolk Ridge.

In extant literature, the bryozoan genus Chaperia Jullien, 1881 comprises 22 named species, seven of them solely fossil, with the two earliest temporal records dating from the New Zealand Oligocene. All but four of the putative extant species are confined to the Southern Hemisphere. A 2009 New Zealand checklist accepted three named indigenous Chaperia species (one of them misidentified), plus two yet-to-be named species and one other of uncertain identity. Restudy of this material, plus examination of Chaperia in new collections from throughout New Zealand's Exclusive Economic Zone (EEZ) and the Norfolk Ridge, has yielded additional new species, such that 17 species of Chaperia are now recognised in the EEZ at the present day, 15 of them new to science. Vestigial ooecia have been found in all of the species and small, sparsely distributed adventitious avicularia have also been discovered in two of them. The taxonomic usefulness of the available morphological characters of Chaperia species is discussed, as is the status of all other putative extant species and their relationship to the Zealandian species. It is hypothesized that Chaperia evolved from an austral Chaperiopsis ancestor in the late Paleocene or Eocene.