Benthic hydroids (Cnidaria: Hydrozoa) from Peter I Island (Southern Ocean, Antarctica)

Twenty-three species of benthic hydroids, belonging to eight families and 13 genera, were found in a hydroid collection from Peter I Island, collected during both the Bentart 2003 and Bentart 2006 Spanish expeditions with BIO Hespérides in 2003 and 2006. Fourteen out of the 23 species constitute new records for Peter I Island, raising the total number of known species in the area to 30, as also do seven out of the 13 genera. The majority of the species are members of the subclass Leptothecata; the subclass Anthoathecata being scarcely represented. Sertulariidae is the family with the greatest number of species in the collection, with eight species (35%), followed by Lafoeidae with five (22%). Symplectoscyphus with four species (17%) and both Antarctoscyphus and Halecium with three (13%), including H. frigidum sp. nov., were the most diverse genera. Twenty species (ca. 77%) are endemic to Antarctic waters, either with a circum-Antarctic (11 species, ca. 42%) or West Antarctic (9 species, ca. 35%) distribution. Twenty-four (ca. 92%) are restricted to Antarctic or Antarctic/sub-Antarctic waters; only two species have a wider distribution. Peter I Island hydroid fauna is composed of typical representatives of the Antarctic benthic hydroid fauna, though it is characterized by the low representation of some of the most diverse and widespread Antarctic genera (Schizotricha and Staurotheca).     

The life cycles of Ocfotiara russelli and Sfomofoca atra (Cnidaria, Anthomedusae, Pandeidae)

The previously unknown life cycles of Ocioiiara russelli and Stomoroca alru are described. Both species present differentiated hydroids and medusae. From the morphology of the newly liberated medusae both species are referred to the Pandeidae and, from the presence of a manubrial peduncle, to the subfamily Stomotocinae. together with Timoides . Some aspects of feeding and gonad growth are described and discussed.     

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.The present work is an addition to the special issue “Macrobenthic studies at Bouvet island”, presenting work carried out from on board RV Polarstern in 2003/2004 and published in Polar Biology 29 (2006)     

Two new gorgonian genera (Octocorallia: Primnoidae) from Southern Ocean waters

Tauroprimnoa austasensis gen. nov., sp. nov. and Digitogorgia kuekenthali gen. nov., sp. nov. are described and illustrated from Southern Ocean waters. The most distinctive characters of the newly proposed genera are, in Tauroprimnoa, the existence of four marginal scales, two abaxials with a strong thorn, and the presence of a single abaxial longitudinal row of body scales. In the case of Digitogorgia, the colony branching pattern, the structure of the opercular scales, and the presence of a complete cycle of accessory opercular scales are the distinct features to distinguish it from previously known genera. Tauroprimnoa austasensis sp. nov. is reported from the Eastern Weddell Sea, Antarctica, while Digitogorgia kuekenthali sp. nov. has been found in the SubAntarctic waters off Burdwood Bank and, in the south east of Isla Nueva in Chilean Patagonia.     

A new species of Vanbenedenia Malm, 1860 (Copepoda: Lernaeopodidae) from the Southern Indian Ocean

A rare find of the elusive genus Vanbenedenia off the south-eastern coast of South Africa on a Hydrolagus sp. proved to be an as yet undescribed species. Vanbenedenia hydrolagae n. sp. differs from the three other species of the genus by virtue of the relative length of the second maxillae, the absence of multiple setae on the exopod of the first maxilla and the bifid nature of the sclerotised hook and sub-terminal seta of the maxilliped. SEM micrographs provided information on the mouth-cone.     

Description of two new species of Santelmoa (Teleostei, Zoarcidae) from the Southern Ocean

Detailed examination of eelpouts in collected material from the Gerlache Strait and the Bellingshausen Sea, during the Spanish Antarctic Expeditions Bentart 03 and Bentart 06, and from the Bransfield Strait, during the Danish Galathea 3 Expedition, at depths between 1,056 and 1,837?m, revealed two undescribed species of Santelmoa Matallanas 2010. Herein, Santelmoa fusca sp. nov. and Santelmoa antarctica sp. nov. are described on the basis of twelve specimens. Santelmoa fusca can be separated from all other Santelmoa species by the following characters: mouth terminal; two posterior nasal pores; lateral line double; two irregular rows of palatine teeth; dorsal fin rays 109–113; anal fin rays 88–94; vertebrae 27–29?+?87–91?=?114–118; two pyloric caeca well developed; scales reduced to tail; pelvic fins and vomerine teeth present. Santelmoa antarctica can be separated from all other Santelmoa species by the following characters: mouth subterminal; two posterior nasal pores; suborbital pores seven (6?+?1); lateral line double; single row of palatine teeth; supraoccipital dividing the posterior end of frontals; central radials notched; dorsal fin rays 109–112; anal fin rays 89–93; vertebrae 27?+?89–92?=?116–119; two pyloric caeca well developed; scales, ventral fins and vomerine teeth present. Santelmoa fusca and S. antarctica can readily be separated from each other by squamation (reduced to tail vs. on the tail and on the posterior part of body); suborbital pore pattern (6?+?0 vs. 6?+?1), as well as several morphometric characters. The relationships of the two new species with congeners are discussed.     

Medusae of the genus Rhabdoon (Hydrozoa: Anthomedusae: Tubularioidea) in the Arctic Ocean

One hundred and three specimens of juvenile and mature one-tentacle, relatively small-sized hydromedusae of unclear systematic position were found in the zooplankton collections from the Arctic Ocean. Examination of the mature specimens led to the conclusion that their morphology fits with the last diagnoses of the genus Rhabdoon (Anthomedusae) and that they belong to the species named here as R. reesi. The study of the morphology and cnidome composition of immature medusae suggested them to be young stages of the same species. The comparative study of these juvenile forms with Yakovia polinae, the medusae described previously from the Arctic as a new genus and new species, suggested Y. polinae to be a junior synonym of R. reesi. The distribution of R. reesi in the Arctic Ocean is mapped according to recent and historical records.     

Brittle stars from Southern Ocean (Echinodermata: Ophiuroidea)

The present biogeographic study on the ophiuroid fauna from the Southern Ocean (SO) contains an updated checklist, based on a compilation of all the published information provided for the Antarctic and sub-Antarctic regions as well as the information available in SCAR-MarBIN database. Faunal composition and geographical and bathymetric distribution are included. So far, 219 species have been recorded, of which 126 are endemic to the SO, 76 are exclusive to Antarctic waters, and 30 are exclusive to sub-Antarctic waters. This study corroborated the circumpolar and eurybathic character of the ophiuroid fauna of the SO, but some differences are discussed when considering shelf and deep-sea fauna in the whole SO, or in the Antarctic and sub-Antarctic regions separately. The biogeographic affinities of 17 areas considered in the SO are revised, based on a presence/absence datamatrix of the 219 species. This similarity analysis shows three main groups, two of them including sub-Antarctic areas and one for Antarctic areas. The faunal movement patterns between the main geographical connections have been based on historical site records of each species. These movements have a level of faunal exchange that exceeds that of other Antarctic benthic groups. Such movements are mainly from Antarctic and sub-Antarctic regions to the subtropical waters of South America, and from New Zealand and southern Australian waters to sub-Antarctic areas. In this context, the origin of the ophiuroid Antarctic fauna is discussed.     

Southern Ocean diversity: new paradigms from molecular ecology

Southern Ocean biodiversity reflects past climate, oceanographic, and tectonic changes. Molecular data from contemporary populations carry signatures of these processes. Here, we review new molecular studies on Southern Ocean benthic fauna. Many of these studies focus on species with extensive geographic or bathymetric distributions, and resolve taxonomic questions. Reviewing all available data, we show that, in addition to reflecting life-history characteristics, the molecular signals found in these studies provide an insight into how species survived the last glacial maximum (LGM). We identify molecular signatures that are characteristic of surviving glacial cycles in small refugia on the continental shelf and distinguish them from molecular signatures that are indicative of surviving glacial cycles in the deep sea.     

Sarcotretes (Copepoda: Pennellidae) parasitizing myctophid fishes in the Southern Ocean: new information from seabird diet

Copepods are common parasites of marine fishes, but little information is available on the biology of species that parasitize mesopelagic fishes in oceanic waters. In this study, we report the finding of large numbers of Sarcotretes spp. (n = 2340) in dietary samples of king penguins collected at Crozet and the Falklands Islands. Analysis of penguin food indicates that S. scopeli Jungersen parasitizes myctophid fishes, Protomyctophum tenisoni (Norman), in the southern Indian Ocean and P. choriodon Hulley in the southern Atlantic. It suggests that the much rarer S. eristaliformis (Brian) also parasitizes myctophids, but the host species of that copepod remains to be determined. The new data add significant information concerning the hosts and distribution of Sarcotretes spp. in the Southern Ocean and emphasize the usefulness of ichthyophagous predators in revealing valuable information on the biology of organisms that parasitize their prey.     

A new octocoral genus (Cnidaria: Anthozoa) from Antarctic waters

Sphaeralcyon weddellensis gen. nov. et sp. nov. is described and illustrated from three colonies collected in the eastern Weddell Sea on the Polarstern cruises ANT V/3 and ANT VI/3. The new genus is compared with three closely related alcyoniid genera, all having capitate or mushroom-shaped colonies and dimorphic polyps. Sphaeralcyon is readily distinguishable from Malacacanthus by the presence of sclerites (absent in the latter genus), and from Anthomastus by sclerite shape, mainly in the form of tuberculate spheroids, and by the horny periderm on the stalk (absent in Anthomastus). Sphaeralcyon also differs from Verseveldtia in the set of sclerites, which are elongate spiny rods and a different type of tuberculate spheroid, and in the presence of eight-points as anthocodial armature (absent in Verseveldtia). The discovery of this new genus lends further support to the notion that diversity in benthic communities in Antarctica is higher than suggested by previous studies. Accepted: 6 December 1999     

Asteroids,ophiuroids and holothurians from the southeastern Weddell Sea (Southern Ocean)

Until the early 1980s, the composition and distribution of the asteroid (starfish), ophiuroid (brittle star) and holothurian (sea cucumber) bottom fauna of the southeastern Weddell Sea was virtually unknown. This southernmost part of the Atlantic sector of the Southern Ocean is a typical high-latitude Antarctic region located in the circumpolar permanent pack-ice zone. It became accessible for large-scale scientific surveys only through the availability of modern ice-breaking research vessels, such as the German RV “Polarstern”. Here, we describe a dataset of the faunal composition and abundance of starfish, brittle star and sea cucumber assemblages in this area, based on collections from trawl catches carried out during three “Polarstern” cruises in 1983, 1984 and 1985. The set comprises a total of 4,509 records of abundances of 35 asteroid species (with a total of 2,089 specimens) and 38 ophiuroid species (with a total of 18,484 specimens) from 34 stations, as well as of 66 holothurian species (with a total of 20,918 specimens) from 59 stations including zero-abundances (absences). A synthesizing zoogeographical community analysis confirms the presence of three distinct assemblages of asteroids, ophiuroids, and holothurians with highest species richness on the eastern shelf. Overall, starfishes, brittle stars and sea cucumbers were present at all sites investigated in the study area but composition and abundance of asterozoan (asteroids and ophiuroids together) and holothurian fauna varied considerably. A synthesizing zoogeographical community analysis confirms the presence of three distinct assemblages of asteroids, ophiuroids, and holothurians with highest species richness on the eastern shelf. In the case of asterozoans, water depth and latitude seemed to be the most important drivers of assemblage distribution and composition. One of the holothurian assemblages was part of the rich macrozoobenthic community dominated by a diverse and abundant epifauna, mainly sponges and gorgonians. Another one was mainly composed of vagrant deposit-feeding species inhabiting a predominantly non-colonised substratum. In addition, a mixed holothurian assemblage was identified.     

Bathylagus niger sp. nova (Bathylagidae, Salmoniformes) a new species of Bathylagus from the subpolar waters of the Southern Ocean

Bathylagus niger sp. nova from subantarctic waters of the Southern Ocean is described. This species differs from other representatives of the genus in its combination of the following characters: 23–30 (usually 26–27) rakers on the first gill arch, 20–23 rays in the anal fin, 10–12 rays in the dorsal fin, 40–42 scale pockets in the lateral line, 45–48 (usually 46–47) vertebrae, 4–7 (usually 5–6) pyloric caeca, the greatest body depth is in adults 19–22% SL, and the average head is 21–23% SL.     

A new chondrophorine (Cnidaria,Hydrozoa) from the cadiz formation (Middle Cambrian) of California

We describe a new species of chondrophorine hydrozoan,Palaelophacmaea valentinei sp. nov., from the early Middle Cambrian part of the Cadiz Formation of the Marble Mountains of southeastern California. This find extends the stratigraphic range of this genus into the early Middle Cambrian and its geographic range into the western United States. We review various chondrophorine-like fossils and present a tentative chondrophorine phylogeny in light of this find.     

Hansenomysis anaramosae n. sp., a new suprabenthic mysid (Crustacea: Mysidacea: Petalophthalmidae) from the Bellingshausen Sea (Southern Ocean)

A new petalophthalmid mysid, Hansenomysis anaramosae n. sp., is described from specimens sampled with a suprabenthic sled in the Bellingshausen Sea (Southern Ocean). Hansenomysis anaramosae is clearly distinguishable from its closest congener, H. angusticauda Tattersall, by the carapace sculpturing, the rostrum produced into a spine-like process, the shape and armature of the antennal scale, eyeplate, and telson. This new species is the fourth Hansenomysis species described from the Southern Ocean. A key to these Antarctic species is presented.     

Description of two new genera, Santelmoa and Bentartia and two new species of Zoarcidae (Teleostei, Perciformes) from the Southern Ocean

Two new genera of lycodine zoarcid fish, Santelmoa and Bentartia, and two new species, Santelmoa carmenae and Bentartia cinerea, are described from 13 specimens collected from the Gerlache Strait, Southern Ocean, at 1,056-m depth. Santelmoa can be distinguished from all other lycodine genera by the combination of the following characters: anterior portion of frontals fused; scapular foramen open; ceratohyal–epihyal articulation interdigitating; cranium narrowed; supratemporal commissure and occipital pores absent; intercalar reaching the prootic; parasphenoid wing well developed; palatal arch well developed; posterior hyomandibular ramus short; post-temporal ventral ramus well developed; six branchiostegal rays; vertebrae asymmetrical; pelvic fin rays ensheathed; scales, lateral line, pyloric caeca, palatine and vomerine teeth present. Bentartia differs from the remaining lycodine genera by the following combination of characters: basioccipital and exoccipitals fused; supraoccipital–exoccipital articulation broadly contacting; ceratohyal–epihyal articulation interdigitating; post-temporal ventral ramus weak; two posterior nasal pores; cranium narrowed; supratemporal commissure and occipital pores absent; intercalar set posteriorly; palatal arch well developed; posterior hyomandibular ramus not elongate; parasphenoid wing high; six branchiostegal rays; vertebrae asymmetrical; pelvic fin rays ensheathed; scales, lateral line, pyloric caeca, palatine and vomerine teeth present. The relationships of the two new genera are discussed.