Review of the family Halopterididae (Hydrozoa, Cnidaria)

All genera and species of the hydrozoan family Halopterididae are reviewed. Where material was available, species are described and figured and the extent of morphological variation is assessed as far as possible. The re-examined material includes samples from the Challenger, Siboga, and Galathea expeditions. Numerous types were re-examined and taxonomic revisions made where necessary. For several nominal species lectotypes are designated. Two new species are described: Antennella kiwiana from New Zealand and Halopteris platygonotheca, a wide spread species from the Indo-Pacific Ocean. Halopteris buskii var. peculiaris (Billard, 1913) is raised to species level as Halopteris peculiaris. Several species are sunk into synonymy: Plumularia balei Billard, 1911 is referred to Antennella varians (Billard, 1911); Antennella variabilis Fraser, 1936 is referred to A. quadriaurita Ritchie, 1909; Plumularia nuttingi Billard, 1911 is referred to Halopteris polymorpha (Billard, 1913); Thecocaulus heterogona Bale, 1924 is referred to Halopteris crassa (Billard, 1911); Halopteris constricta Totton, 1930 is referred to H. minuta (Trebilcock, 1928); Corhiza mortenseni Millard, 1968 is referred to Corhiza complexa (Nutting, 1905); Plumularia obconica Kirchenpauer, 1876, Heteroplon pluma Allman, 1883, and Plumularia armata Allman, 1883 are all referred to Halopteris buskii (Bale, 1884). Antennella siliquosa (Hincks, 1877), Halopteris alternata (Nutting, 1900), and Halopteris tenella (Verrill, 1874) are recognised as valid species. The recognised genera of the Halopterididae are: Antennella Allman, 1887, Halopteris Allman, 1887, Monostaechas Allman, 1877, Schizotricha Allman, 1883, Antennellopsis Jäderholm, 1896, Corhiza Millard, 1962, Gattya Allman, 1886, Calvinia Nutting, 1900, Nuditheca Nutting, 1900, Astrolabia Naumov, 1955, Anarthoclada Naumov, 1955, and Pentatheca Naumov, 1955. The validity of the generic division is discussed; only minor emendations are made for the genera Halopteris and Schizotricha.