A.L. Peña Cantero

How rich is the deep-sea Antarctic benthic hydroid fauna?

The bathymetric distribution of the 155 known species of Antarctic benthic hydroids has been studied with the aim of determining bathymetric groups and estimating the richness of the deep-sea Antarctic benthic hydroid fauna. Six bathymetric groups could be recognized on the basis of vertical zonation patterns. Most species have wide bathymetric ranges, but must nevertheless be considered shelf species. Although 62 species of benthic hydroids have been found in the Antarctic deep-sea, only 10 are strict inhabitants of that area. An inverse relative dominance between anthoathecate and leptothecate hydroids has been observed, with the former being more frequent in shallow waters.The bathymetric distribution of the 155 known species of Antarctic benthic hydroids has been studied with the aim of determining bathymetric groups and estimating the richness of the deep-sea Antarctic benthic hydroid fauna. Six bathymetric groups could be recognized on the basis of vertical zonation patterns. Most species have wide bathymetric ranges, but must nevertheless be considered shelf species. Although 62 species of benthic hydroids have been found in the Antarctic deep-sea, only 10 are strict inhabitants of that area. An inverse relative dominance between anthoathecate and leptothecate hydroids has been observed, with the former being more frequent in shallow waters.

Species of Staurotheca Allman, 1888 (Cnidaria: Hydrozoa) from recent antarctic expeditions with R. V. Polarstern, with the description of six new species

Thirteen species of the genus Staurotheca Allman, six of which are new to science, have been studied. The material originates from the Weddell Sea region and was collected by several antarctic expeditions with the R. V. Polarstern. Each species is described and figured and its systematic position among allied species discussed. Current data concerning autecology and geographical distribution of each species are discussed. Re-definitions of the genera Staurotheca Allman and Thuiaria Fleming are presented. The species formerly referred to the genus Selaginopsis Allman and found in the southern hemisphere are included in Staurotheca, while the northern ones are sunk in Thuiaria.

Species of Staurotheca Allman, 1888 (Cnidaria: Hydrozoa: Sertulariidae) from US Antarctic expeditions, with the description of three new species

Seventeen species of the genus Staurotheca Allman have been studied, three of which are new to science (Staurotheca abyssalis sp. nov., S. densa sp. nov. and S. profunda sp. nov.). The material studied was collected by several US Antarctic expeditions. Each species is described and figured, the systematic position amongst allied species discussed and available data concerning autecology and geographical distribution given. The remaining six known species of the genus are also considered, regarding synonymy, autecology and geographical distribution. The type material of two poorly known species of Staurotheca, S. juncea (Vanhöffen) and S. pachyclada (Jäderholm) has been re-examined, re-described and figured. Finally, a general survey of the bathymetrical and biogeographical distribution of the known species of Staurotheca is given.

Species of Oswaldella Stechow, 1919 (Cnidaria: Hydrozoa: Kirchenpaueriidae) from US Antarctic expeditions, with the description of three new species

Seventeen species of the genus Oswaldella Stechow have been studied, three of which are new to science (Oswaldella frigida sp. nov., O. medeae sp. nov. and O. monomammillata sp. nov.). The material studied was collected by several US Antarctic expeditions. Each species is described and figured, the systematic position amongst allied species is discussed and available data concerning autecology and geographical distribution are given. The remaining eight known species of the genus are also considered, regarding synonymy, autecology and geographical distribution. Finally, a general survey of the bathymetrical and biogeographical distribution of the known species of Oswaldella is given.

On the species of Filellum Hincks, 1868 (Cnidaria: Hydrozoa) with the description of a new species

The species of the genus Filellum Hincks have been reviewed and a species new to science, Filellum disaggregatum sp. nov., is described and figured, the coppinia of this species being much different from those of the other members of the genus. The coppinia of Filellum serratum Clarke, hitherto unknown from the Mediterranean Sea, is also described and figured. A key for the identification of the species of the genus is also presented.

On Antarctoscyphus (Cnidaria, Hydrozoa), a new genus of antarctic hydroids and the description of two new species

Abstract A new genus of the hydroid family Sertulariidae is established. Several species formerly assigned to the genus Symplectoscyphus Marktanner-Turneretscher, 1890 are included. A review of those species is given, including their main features along with some remarks. Two species new to science are added; the material of those species was collected in the Scotia Sea by the Spanish Antarctic Expedition “Antártida 8611”. Present autecological data are discussed.

Antarctic hydroids (Cnidaria, Hydrozoa) of the families Campanulinidae, Lafoeidae and Campanulariidae from recent Antarctic expeditions with R.V. Polarstern, with the description of a new species

Species of the thecate hydroid families Campanulinidae, Campanulariidae and Lafoeidae have been studied. The material studied originates from the Weddell Sea and was collected by several French and German Antarctic expeditions with R.V. Polarstern. Fourteen species were found, three belonging to Campanulinidae, four to Campanulariidae and seven to Lafoeidae, one of these new to science (Filellum magnificum sp. nov.). The coppinia of Lafoea gaussica Vanhöffen, 1910, is described for the first time as well as the gonothecae of Opercularella belgicae (Hartlaub, 1904). A neotype is indicated for Filellum antarcticum (Hartlaub, 1904). Available data concerning autecology and geographical distribution for each species are given, as well as a description and figures when considered necessary.

Species of Schizotricha Allman, 1883 (Cnidaria: Hydrozoa: Halopterididae) from US Antarctic expeditions with the description of two new species

Twelve species of the genus Schizotricha Allman have been studied, two of which are new to science (Schizotricha heteromera sp. nov. and S. trinematotheca sp. nov.). The material studied was collected by several US Antarctic expeditions. Each new species is described and figured, the systematic position amongst allied species discussed and available data concerning autecology and geographical distribution given. The remaining 10 species are considered regarding diagnosis, autecology and geographical distribution. Finally, a general survey of the bathymetrical and biogeographical distribution of the known species of Schizotricha is given.

Species of Symplectoscyphus Marktanner-Turneretscher, 1890 (Cnidaria: Hydrozoa, Sertulariidae) from recent Antarctic expeditions with R.V. Polarstern , with the description of four new species

Fifteen species of the genus Symplectoscyphus Marktanner-Turneretscher have been studied, four of which are new to science (Symplectoscyphus anae sp. nov., S. frigidus sp. nov., S. sofiae sp. nov. and S. weddelli sp. nov.). The material studied originates from the Weddell Sea and was collected by several French and German Antarctic expeditions with R.V. Polarstern. Each species is described and figured, the systematic position amongst allied species discussed and available data concerning autecology and geographical distribution given. The type material of five poorly known species of Symplectoscyphus, S. aggregatus (Jäderholm), S. cumberlandicus (Jäderholm), S. glacialis (Jäderholm), S. hero Blanco and S. plectilis (Hickson and Gravely), has been re-examined, re-described and figured. Finally, a general survey of the bathymetrical and biogeographical distribution of the known Antarctic species is given.

Benthic hydroids (Cnidaria, Hydrozoa) from off Bouvet Island (Antarctic Ocean)

Twenty-seven species of benthic hydroids have been found in a small collection from off Bouvet Island (Antarctic Ocean). The material was obtained during the XXI/2 German Antarctic expedition with R.V. Polarstern 2003–2004. Of the 27 species collected, 21 were unknown from those waters. Consequently, the number of known species of benthic hydroids from the area has risen to 32, representing a high diversity location for this group in the Southern Ocean considering the sampling effort made. All species, including those previously known from Bouvet waters, are considered with respect to geographical distribution.