Juan Moreira

Assemblages of peracarid crustaceans in subtidal sediments from the Ría de Aldán (Galicia, NW Spain)

Peracarid crustaceans inhabit many marine benthic habitats and are good indicators of environmental conditions. There is, however, a lack of information about diversity and distribution of peracarid crustaceans on the shallow subtidal sediments of the Galician rias. In the summer of 1997, 27 subtidal stations were sampled in the Ría de Aldán, a ria on the southern margin of the mouth of the Ría de Pontevedra (Galicia, NW Spain). A total of 16,191 peracarid individuals were collected, comprising 125 species belonging to five orders. Amphipods were dominant in number of species and individuals, followed by isopods and cumaceans. Multivariate analyses of these data indicated that depth and sediment granulometry were major determinants of distribution and composition of peracarid assemblages in the ria.

Distribution and diversity of the Opheliidae (Annelida, Polychaeta) on the continental shelf and slope of Iceland, with a review of the genus Ophelina in northeast Atlantic waters and description of two new species

The diversity, taxonomy and distribution of the Opheliidae (Annelida: Polychaeta) in Icelandic waters is reviewed based on material collected during the BIOICE project. Nine opheliid species are recorded from Iceland; of these, three were previously reported in the area (Ophelia limacina, Ophelina cylindricaudata and O. acuminata), four are new for Icelandic waters (Ammotrypanella cf. arctica, Ophelina abranchiata, O. helgolandica and Tachytrypane jeffreisii), and two are new to science. Ophelina basicirra sp. nov. is distinguished by having a narrow anal tube with one short proximal anal cirrus in ventral position. Ophelina bowitzi sp. nov. is characterized by the small size of its anterior branchiae, which become larger in the middle and posterior body regions, and by an upwardly bent anal tube that is wide at the base and narrowing distally. The genera Euzonus, Armandia and Polyophthalmus are not represented in the BIOICE samples. The distribution of each species off Iceland is presented; one species is restricted to shallow waters of northwestern fjords, three species are found south of the GIF Ridge, and five species are circumicelandic. Several body characters with taxonomic relevance in some species are reviewed based on SEM images. Furthermore, as a first step towards a future revision of the genus Ophelina Örsted 1843 in North Atlantic waters, the status of each species originally described or subsequently reported from the area is commented on, and a key to the currently valid species is presented. Ophelina longicephala Hartmann-Schröder, 1977, formerly a subspecies of O. delapidans (Kinberg, 1866), is raised to species status.

Diversity and distribution of peracarid crustaceans in shallow subtidal soft bottoms at the Ensenada de Baiona (Galicia, N.W. Spain)

Peracarida are an important component of soft sediment faunas and are considered good indicators of the quality of water and sediments. Nevertheless, little is known about the diversity and distribution of peracarid crustaceans on the shallow subtidal sediments of the Galician Rias (N.W. Spain), and about the Ensenada de Baiona in particular. Therefore, the peracarid fauna of this inlet was studied at 21 subtidal sites in December 1995. Sampling yielded 5749 individuals belonging to 91 different taxa. The number of species was particularly high when compared to values recorded from similar geographical areas. Amphipods were dominant in numbers of individuals and species. By means of multivariate analyses, several assemblages were determined whose species composition was related to the distribution of sediments in the inlet. Los Peracarida constituyen un componente importante de la fauna en fondos blandos marinos y son considerados un buen indicador de la calidad del agua y los sedimentos. Sin embargo, existe poca informacion sobre la diversidad y distribucion de los crustaceos peracaridos en los sedimentos submareales de las Rias de Galicia en general, y en particular de la Ensenada de Baiona (N.W. Espana). Debido a ello, la fauna de peracaridos de esta ensenada fue estudiada en 21 estaciones de muestreo submareales en Diciembre de 1995. Se obtuvieron 5749 individuos pertenecientes a 91 taxones diferentes. El numero de especies total fue particularmente alto en comparacion a los referidos de otras areas geograficas similares. Los anfipodos constituyeron el grupo dominante en numero de individuos y de especies. Los analisis multivariante permitieron distinguir varias asociaciones de peracaridos coincidentes a grandes rasgos con la distribucion de los sedimentos en la ensenada.

Taxonomy and distribution of the genus Amphicteis (Polychaeta: Ampharetidae) collected by the BIOICE project in Icelandic waters

Based on material collected during the BIOICE project off Iceland, four species of polychaetous annelids belonging to the genus Amphicteis Grube, 1850 (Polychaeta: Ampharetidae) were found: Amphicteis gunneri, Amphicteis ninonae, Amphicteis vestis and Amphicteis wesenbergae sp. nov. The differences between A. gunneri and A. ninonae, two species usually confused in the literature, are reviewed. Amphicteis vestis is described from newly collected material and its taxonomy in relation to other ampharetid taxa with modified notopodia is discussed. Amphicteis wesenbergae sp. nov. is described; the new species is characterized by the presence of long, slender and evenly tapered paleae, and long dorsal cirri on thoracic and abdominal neuropodia. Several body characters with high value in Amphicteis taxonomy, particularly the dorsolateral protrusions of abdominal chaetigers called rudimentary notopodia, are reviewed using scanning electron microscopy. A key to species of the genus Amphicteis described or reported in European Boreo-Arctic waters is provided.

Peracarid assemblages of Zostera meadows in an estuarine ecosystem (O Grove inlet, NW Iberian Peninsula): spatial distribution and seasonal variation

The Galician rias are singular and complex estuarine systems of great economic importance. Seagrasses are key elements of the ecosystem and favor the maintenance of high species diversity in benthic communities. Nevertheless, the ecological role of seagrass meadows in the Galician rias has been only partially assessed. Peracarid crustaceans are an important component of soft-bottom faunas and have great importance for the structure of benthic assemblages. In this work, species diversity, patterns of distribution and seasonal fluctuations of peracarids (Crustacea, Peracarida) are studied in estuarine sediments colonized by two species of Zostera (Z. marina and Z. noltii) at the O Grove inlet (Ría de Arousa, Galicia, NW Iberian Peninsula). The spatial distribution of peracarid assemblages was characterized by high numerical dominances due to a few species, particularly tanaidaceans. The temporal study at a Z. marina meadow showed a strongly seasonal pattern defined by great fluctuations of the amphipod population, the latter being the dominant group in abundance and number of species. The highest numbers of species and individuals were observed in September, with minimum values in March. Analyses pointed out a high correlation among the granulometric features of the studied bottoms and the faunistic attributes. Nevertheless, the presence of the seagrasses should influence in a major way the hydrodynamic and sedimentary features of the habitat and utterly the spatial and temporal patterns observed in the peracarid assemblage in the O Grove inlet.

Sphaerodoridae (Annelida: Polychaeta) from the Bellingshausen Sea (Antarctica) with the description of two new species

The examination of polychaete collections obtained during the Spanish Bentart 2006 expedition to the Bellingshausen Sea (Antarctica) revealed the presence of several sphaerodorid species. In this work, species belonging to the genera Sphaerodorum Örsted, 1843, Ephesiella Chamberlin, 1919, Clavodorum Hartman and Fauchald, 1971 and Sphaerephesia Fauchald, 1972 are reported including two new species belonging to Sphaerodorum and Sphaerephesia, respectively. A specimen identified as Ephesiella sp. might also represent a new species but, due to its poor state of preservation, a formal description is not possible yet. Furthermore, Sphaerodoropsis polypapillata Hartmann-Schröder and Rosenfeldt, 1988 is transferred to the genus Clavodorum Hartman and Fauchald, 1971 after examination of the type series and specimens obtained from the Bellingshausen Sea.

Polychaetes of the genus Ampharete (Polychaeta: Ampharetidae) collected in Icelandic waters during the BIOICE project

Based on material collected during the BIOICE project off Iceland, the taxonomy and distribution of eight species of polychaetous annelids belonging to the genus Ampharete (Polychaeta: Ampharetidae) are reviewed. Five of these species were previously reported in the area: Ampharete acutifrons, Ampharete borealis, Ampharete finmarchica, Ampharete octocirrata and Ampharete petersenae; two are new to Icelandic waters: Ampharetebaltica and Ampharete lindstroemi; and one is new to science: Ampharete villenai sp. nov. A. petersenae was found for the first time after the original description and is redescribed. A. villenai sp. nov. is primarily characterized by the size, shape and disposition of the paleae, a special kind of chaetae located on the first body chaetiger. Several body characters of high taxonomic relevance in Ampharetidae are reviewed under the SEM. The distribution of each species off the coast of Iceland and a key to all species recorded in European Boreo-Arctic waters is provided.

Redescription of Terebellides kerguelensis stat. nov. (Polychaeta: Trichobranchidae) from Antarctic and subantarctic waters

During the Spanish Antarctic expeditions “Bentart” 1994, 1995 and 2003, a number of trichobranchid (Annelida: Polychaeta) specimens were collected and identified initially as Terebellides stroemii kerguelensis McIntosh, 1885, the only known species of the genus widely recognised as valid in Antarctic waters. In the framework of a worldwide revision of the genus Terebellides, a reconsideration of the taxonomic status of this subspecies of the boreal Terebellides stroemii Sars, 1835 is done through the examination of the syntypes of T. s. kerguelensis compared with recent descriptions of the nominal species from Norwegian waters and material from Icelandic waters. Thus, T. s. kerguelensis is regarded as a valid species, T. kerguelensis stat. nov., and redescribed designating a lectotype and paralectotypes. The species is mainly characterised by the presence of an anterior branchial extension (fifth lobe), lateral lappets in five anterior thoracic chaetigers, segmental organs in chaetigers 1, 4 and 5, and first thoracic acicular neurochaetae sharply bent with pointed tips. The biological role of the segmental organs, the presence and disposition of cilia in branchial lamellae and the finding of new structures located in dorsal part of thoracic notopodia are discussed.

Nebalia Pseudotroncosoi N. SP. (Malacostraca: Leptostraca), from South Korea, with a Peculiar Sexual Dimorphism

A new crustacean, Nebalia pseudotroncosoi n. sp. (Malacostraca: Leptostraca), occurs along the southern coasts of Korea. The specimens were collected by light traps in harbors where the bottom consisted of fine sand with some algal mats. The new taxon is distinguished from all other known species of Nebalia by the following characteristics: a rectangular compound eye with two to three small distal lobes; an antennular flagellum that is clearly shorter than the peduncle, with up to 10 articles; the fourth article of the antennular peduncle has only two distal thick setae; the antennular scale is nearly oval with a length that is 1.8 times the width; the second article of the mandibular palp has three distally plumose setae; pleonites 3 to 7 have rounded denticles along their posterior dorsal margins; and the protopod of pleopod 4 lacks serration along the posterior margin. We discuss sexual dimorphism in the genus Nebalia and propose the necessity of describing male traits when reporting new species. We also provide partial sequences of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene from the new species that can be used as a molecular diagnostic characteristic.

A New Species of Leptostraca, Nebalia koreana (Malacostraca: Phyllocarida), from South Korea

ABSTRACT Herein, we report a new species of leptostracan, Nebalia koreana (Malacostraca) collected from the southern and eastern coasts of the Korean peninsula. All the specimens of this species were collected by means of light traps from harbors where the bottoms are sandy and with algal mats. The new species differs from all other known Nebalia in the following characters: the carapace is relatively small, and covers the lateral sides of pleonite 2 and partially the lateral sides of pleonite 3; the fourth article of the antennule has up to five short distal spines; pleonites 3 to 7 have rounded denticles along the posterior dorsal borders; the epipod of thoracopod 7 bears 5 to 6 plumose setae along the posterior margin, which are lacking on the remaining thoracopods; and the protopod of pleopod 4 lacks serration along the posterior border. Only two species of Nebalia have been reported from the tropical or subtropical seas of Asia. Therefore, the new species is the first species of Nebalia found in the temperate zone of Asia. Additionally, type localities and world distribution of the genus Nebalia are provided in this paper.