bluuebunny/crossref_metadata_2025 huggingface dataset:
Mineralogía, origen y valor comercial de las tobas ricas en ceolitas del área de Petrota-Pentalofos, región de Evros, Grecia
Authors: Stamatakis M. G. , Hall A. , Lutat U. , Walsh J. N.
Published: October 2008

Las tobas ricas en cebollitas del área de Petrota-Pentalofos se depositaron en la cuenca de Orejitas durante el Doceno. Alcanzan 100 m de potencia y superan los 15 km de extensión longitudinal. La mayoría de los afloramientos consisten en alternancias de toba de grano muy fino y toba de pómez y lapilli con fragmentos detritos del sustrato Mesozoico de la cuenca. Análisis por difamación de rayos X, microscopía electrónica de barrido y microscopía óptica en muestras de mano y de sondeos demuestran que las tobas están fundamentalmente compuestas por elinoptilolita y cristobalita con una pequeña proporción de constituyentes detritos (cuarzo, esquistos micáceos) y minerales pirotécnicos (feldespato, cuarzo, botita). Pequeñas cantidades de morenita aparecen ocasionalmente en algunos de los afloramientos del norte cercanos a lavas. Análisis químicos de las tobas mediante ICP-AES indican que los magmas originales eran de composición cuarzo-latítica. Las tobas se apoyan sobre un basamento metamórfico pre-Cenozoico y gradan hacia techo a arenisca y marga. Hay evidencias de que las tobas se depositaron en un ambiente supra- a intra-litoral. Las tobas ceolíticas se originaron como sedimentos volcánicos epielásticos, transportados por el agua desde la fuerza eruptiva. La transformación del vidrio volcánico de las tobas en cebollita y cristobalita fue causada por aguas meteóricas en sistema abierto durante el Terciario. Las rocas ceolíticas se explotan en la actualidad para suplemento alimenticio de animales.
Variabilidad química y mineralógica de las facies glauconíticas del sector norte del margen continental Mar de Alborán
Authors: Domínguez M. C. , García Romero E. , La Iglesia A. , Navarro Gascón J. V. , Santos Sánchez A. , Viedma Molero C.
Published: October 2008

Se han estudiado granos glauconíticos de los sedimentos superficiales de la plataforma y talud continentales (profundidades entre 50 y 225 m) de la Cuenca del Mar de Alborán, frente a la localidad de Benalmádena (Málaga). Se han diferenciado tres tipos morfológicos de granos glauconíticos, cuya abundancia varía en función de su tamaño y de la profundidadglauconíticos a la que se encuentran. Las técnicas de difamación de rayos-X, microscopia electrónica de barrido y microonda electrónica indican una relación entre el color y morfología de los granos y la evolución mineralógica y química en función de la profundidad. La evolución mineralógica consiste en un proceso de reorganización desde fases amorfas y/o esmectíticas hasta fases más ordenadas del tipo glauconita 1M. Dicho ordenamiento estructural va acompañado de un aumento del contenido de K y Si y disminución de Ca, Al y Fe.
Una revisión de los estudios sismotectónicos en Cuba
Authors: Cotilla Rodríguez M. O.
Published: October 2008

Se analizan críticamente las investigaciones sismotectónicas realizadas con metodologías rusa y alemana para Cuba hasta 1994. La aplicación de la segunda metodología ha demostrado ser eficiente en al menos el diagnóstico de dos sismos en Cabo Cruz (26.08.1990 Ms = 5,9 y 25.05.1992 Ms = 6,9) Y otro en San José de las Lajas (09.03.1995 Ms =2,5) y permite sustentar un mecanismo de nudos sismoactivos. Dada la insuficiente información de base no existe un único esquema o mapa de zonas sigmogeneradoras.
Quantification et bilan de matiere de la reaction clinopyroxene-spinelle lors de la formation du plagioclase dans les lherzolites a spinelle
Authors: Ibhi A. , Nachit H. , Berrahma M. , Abia H. , Hernández J.
Published: October 2008

La formación de plagioclasa sódica (Pl) y de vidrio en las peridotitas de Saghro (Anti-Atlas marroquí) y de La Palma (Islas Canarias) se puede explicar como resultado de un proceso de metasomatismo y de fusión parcial de climpyroxeno (Cpx) y espinela (Spl), según la reacción: Cpx + Spl + L1 ⇔ Pl + Spl(Cr) + L2 Se han calculado las proporciones volumen de las diferentes fases implicadas en la reacción y se han realizado los balances de masa. Se demuestra que la reacción se produce a volumen constante y traduce los siguientes intercambios: - Aporte de Na, Ti, Fe2+ y Fe3+.- Pérdida de Si, Ca, Mg y 02
Zeolitas y minerales cálcicos de baja temperatura en las pegmatitas graníticas del plutón de La Cabrera (Sistema Central Español)
Authors: González del Tánago J. , La Iglesia A.
Published: October 2008

La actividad hidrotermal tardía que se produjo en el plutón granítico de La Cabrera desarrolló en algunas cavidades miarolíticas y pegmatitas una serie de asociaciones minerales de temperatura decreciente. Entre éstas, son de especial interés las cálcicas de media-baja temperatura, que resultan únicas en el Sistema Central Español. Los minerales más característicos que aparecen en ellas, además de calcita, son: prehnita, laumontita, estilbita-(Ca), heulandita-(Ca), chabasita-(Ca), datolita, fluorapofilita y bavenita. Todos ellos han sido caracterizados por difracción de rayos X y análisis térmico. Se contemplan también sus características químicas, incluyendo las de la babingtonita que aparece de manera accesoria. Las condiciones de máxima actividad hidrotermal tuvieron lugar hacia 250 ± 50° C, disminuyendo a partir de los 140° C. Paralelamente al enfriamiento, se produjo un aumento de la fCO2, que provocó la formación de calcita.
Climate and evolution: implications of some extinction patterns in African and European Machairodontine Cats of the Plio-Pleistocene
Authors: Turner A. , Antón M.
Published: October 2008

Recent discussions of correlations between global climatic change and evolution of the African Plio-Pleistocene biota have revealed apparent discrepancies between the timing and significance of events recorded in different data sets. The most notable differences have occurred in relation to a major shift in the ratio of marine oxygen isotopes by 2.5 myr and claims for a causally related transition in the biota. Vegetational changes recorded in palaeosol stable isotope values suggest that the major increase in more open vegetation occurs later ∼1.7 myr. We investigate the problem with particular reference to events at 1.7 myr and the African extinctions of machairodont cats that take place in their aftermath, since extinctions of such eurytopic taxa are likely to mark significant changes in conditions. We compare the pattern of such extinctions with those of similar or identical taxa in Eurasia and the New World, and suggest that a major environmental change is clearly indicated in each case. It is likely that the African vegetational changes recorded ∼1.7 myr represent a terrestrial response to global climatic changes recorded in marine core records ∼1.9 myr.
El elefante fósil de Buelna (Asturias). Nota preliminar
Authors: Mazo A. V.
Published: October 2008

Un elefante fósil encontrado en una cueva próxima a Buena (Asturias) se identifica como Elephas antiquus (Falconer & Cautley). Este estudio preliminar se basa en las características morfológicas y métricas de un fémur y una hemipelvis; restos que forman parte de un individuo adulto bastante completo que aún permanece sin extraer. Cronológicamente, atribuimos este hallazgo al último interglacial.
Restos fósiles de vertebrados en el yacimiento de «El Recuenco» (Guadalajara)
Authors: Pérez B. , Fregenal-Martínez M. A. , Ortega F. , De Miguel L. , Alberdi M. T.
Published: October 2008

El yacimiento de El Recuenco está constituido por un relleno de materiales que proceden de diversas unidades estratigráficas terciarias. Los restos fósiles presentes aparecen muy rodados, fragmentados y la mayoría incluidos en clastos de diferentes litologías. Muy probablemente se trata de fósiles reelaborados, habiéndose producido mezcla de faunas de distinta edad. Se propone una edad de formación plio-pleistocena para la génesis de este depósito.
An evaluation of the residence duration of megacrysts in alkaline magma chambers
Authors: Ibhi A. , Nachit H. , Khatib D. , Abia El H. , Berrahma M.
Published: October 2008

La integración de la ecuación diferencial de la segunda ley de Fick aplicada a la difusión en un sólido semi-infinito, permitió estimar el tiempo de la residencia de los megacristales de olivino incluidos en lavas alcalinas. Los resultados muestran que existen dos grupos de olivino: el primero persiste entre 30 a 34 días, en contacto con el líquido magmático, mientras que, el segundo, solamente lo hace entre 4 a 7 días. Esta distinción está de acuerdo con la observación petrográfica.
La fauna del pleistoceno inferior de la Sierra de Quibas (Abanilla, Murcia)
Authors: Montoya P. , Alberdi M. T. , Blázquez A. M. , Barbadillo L. J. , Fumanal M.ª P. , Van der Made J. , Marín J. M. , Molina A. , Morales J. , Murelaga X. , Peñalver E. , Robles F. , Ruiz Bustos A. , Sánchez A. , Sanchiz B. , Soria D. , Szyndlar Z.
Published: October 2008

El yacimiento kárstico cuaternario de la Sierra de Quibas (Abanilla, Murcia) ha proporcionado una amplia lista faunística constituida por 53 especies repartidas entre gasterópodos, miriápodos, anfibios, reptiles, aves y mamíferos. En el conjunto de los gasterópodos destaca Palaeoglandina, un género que se extingue en el resto de Europa durante el Plioceno y que se mantiene como relicto en el Pleistoceno de la Península Ibérica. Dos de las especies de aves determinadas, Gypaetus barbatus y Gerontieus eremita, y una de las serpientes, Elaphe cf. E. sealaris, apenas se hallan representadas en el registro fósil. Hay además varias especies de aves cuya aparición en Quibas supone la primera cita en el Pleistoceno inferior de la Península Ibérica. Entre los mamíferos posee una especial relevancia la presencia del cercopitécido Macaca sylvanus. La asociación de los taxones Arvieola deuealion, Castillomys rivas rivas, Eliomys intermedius, Equus altidens y Capra sp. aff. C. alba permite la correlación con Plines 1, Orce 3 y Venta Micena, entre otros. El yacimiento de Quibas puede situarse, por tanto, antes del final del Pleistoceno inferior, con una antigüedad entre 1.3 y 1 Ma. Por lo que se refiere a las condiciones paleoclimáticas, podemos inferir a partir de la asociación faunística un régimen xerófilo, muy semejante al actual en el área geográfica, aunque quizás con valores de humedad y temperatura algo superiores. El entorno de la cavidad kárstica estaba formado por roquedo calcáreo con áreas abiertas de matorral, pero en las proximidades se desarrollaron humedales y zonas arboladas, como así lo atestigua la presencia de aves y micromamíferos típicos de estos hábitats.
Micromamíferos del sitio Arroyo Seco 2 (provincia de Buenos Aires, Argentina). Sus implicaciones tafonómicas y paleoambientales
Authors: Gómez G. , Prado J. L. , Alberdi M. T.
Published: October 2008

La secuencia del Pleistoceno tardío-Holoceno temprano en Arroyo Seco 2 es una de las más completas del registro de la Región Pampeana. Se distinguen cuatro unidades estratigráficas, tres de ellas contienen abundantes restos de pequeños mamíferos fósiles. Se analizan los huesos fósiles de estas unidades con el fin de determinar los procesos tafonómicos y el hábitat en el que tuvo lugar la acumulación que dio lugar al yacimiento. La mayor parte de los huesos fósiles están rotos con posterioridad al enterramiento. Los huesos procedentes de las unidades inferiores están recubiertos de manganeso (Mn) debido a la oscilación de los niveles del agua como consecuencia de reiterados encharcamientos. Entre la fauna de micromamíferos identificamos tres especies de armadillo (Chaetophractus villosus, Dasypus hybridus y Zaedyus pichiy) y cuatro de roedores (Akodon azarae, Rheitrodon auritus, Ctenomys talarum y Lagostomus maximus). Los datos sobre micromamíferos registrados, sumados a la evidencia de megafauna, indican una transición de condiciones templadas y semiáridas a más húmedas entre 12.000 y 8.500 años AP.
Growth studies on Norway lobster, Nephrops norvegicus (L.), in different areas of the Mediterranean Sea and the adjacent Atlantic
Authors: Mytilineou Chryssi , Castro Margarida , Gancho Paula , Fourtouni Anna
Published: October 2008

A comparative study of the growth of Nephrops norvegicus among different areas in the Mediterranean Sea and the adjacent Atlantic was conducted. MIX and Bhattacharya´s length-based methods were used for age determination. Both methods were used for all the studied areas. For the estimation of the growth parameters two non-linear methods, based on the results of the length frequency analysis, were used; the Gauss-Newton method, implemented by the SAS program, was applied using the results of the MIX and the FISHPARM program using the results of the Bhattacharya´s method. The identification of the age groups and their mean lengths-at-age as well as the estimation of the growth parameters proved to be difficult. A question regarding the adequacy of the von Bertalanffy model was also posed. Remarkable differences were obvious between sexes in the number of identified age groups and their mean lengths-at-age as well as in their growth parameters in all areas. The comparison of the results obtained for the studied areas showed differences, which could not be considered very important except in the case of the Nephrops population of the Alboran Sea, which was characterised by a high growth rate. All other areas seemed to be close; among them the populations from Euboikos Gulf and Catalan Sea being the most different.
Nephrops norvegicus (L.): Comparative biology and fishery in the Mediterranean Sea. Introduction, conclusions and recommendations
Authors: Sardà Francesc
Published: October 2008

The project, financed by the Directorate General XIV of the EC, has undertaken a comparative study on the biology and fisheries techniques of the Norway lobster in Mediterranean member states and adjoining Atlantic areas. The ultimate goal of the project has been to assess the conditions for a global regulation in the area and determine possible differences among exploited stocks. The areas selected are characterised by their importance in Norway lobster catch. The overall duration of the project has been three years. Sampling was concentrated in the first two years. Data analysis was conducted during the second and third years (1993-1995). The countries (areas) involved in the study, together with their target areas, were: Portugal (south coast of Algarve), Spain (Alboran and Catalan Seas), Italy (Ligurian, Tyrrhenian and Adriatic Seas) and Greece (Gulf of Euboikos). In order to make results perfectly comparable, each scientific subject has been developed by a specialised team using a unified and standardised methodology. From the biological standpoint, Norway lobster growth, reproduction, moult and feeding have been compared. Special studies on distribution and genetics have been also conducted. In the fisheries context, a comparison of fishing techniques has been undertaken. The fisheries studies have been complemented with reconstruction of virgin populations, comparison of yield per recruit, sensitivity analysis and transition analysis. Selectivity issues have been object of specific analyses. As a result of these studies, it is evident that Norway lobster populations in the Mediterranean follow a common life-cycle model. The differences among areas reported in this project respond to environmental variation and differential fishing pressure in each area. All populations are exploited near its carrying limit, although overexploitation is unlikely at this stage. However we identified varying levels of exploitation according to study areas: The Catalan, Tyrrhenian and Adriatic Seas populations are exploited at a high level; the Ligurian Sea and Euboikos Gulf populations at an intermediate level; and the Alboran Sea and Algarve populations are at a low level of exploitation. The regulation concepts could be applied globally to the Mediterranean, allowing for the differences observed. It is highly recommended that effort is not increased. It should rather be decreased as new technologies being implemented continuously are by themselves an effort increase. A effort reduction of 20% is desirable to ensure that stocks are maintained at their current levels. This measure should be foremost applied to those areas being subjected to the highest exploitation levels.
Methodological considerations concerning the use of length frequency analysis for growth studies in the Norway lobster, Nephrops norvegicus (L.)
Authors: Castro Margarida , Mytilineou Chryssi , Gancho Paula
Published: October 2008

The structure of length distributions of Nephrops norvegicus was investigated in order to understand the adequacy of length frequency analysis for estimation of growth rates and growth parameters. Samples from two areas were used: the Atlantic Ocean off the South coast of Portugal and the Euboikos Gulf in the Mediterranean. Monthly samples were obtained from October 1993 to October 1995. For each area, month and sex, the samples were analyzed using the program MIX in order to identify the mean length for each of the groups composing the length distributions. The mean values were used to estimate increments between consecutive groups within the same sample. Biological information extracted from the same samples and referring to maturation and molting cycles, was used in conjunction with the mean values estimated in this work to interpret modal progression and growth rates. Results show that modal progression analysis is not appropriate because the modes do not progress in a manner that allows the following of a particular group. Growth rates based on increments verified within each sample were also investigated. This approach proved to be better, although there were still some problems due to large year to year variability and the fact that the magnitude of the increments did not decrease with increasing size. This also poses problems regarding the fitting of growth curves to these data; in particular when deceleration of growth is required, as in the case of the von Bertalanffy growth curve.
Meiofauna communities from the Straits of Magellan and the Beagle Channel
Authors: Chen G. C. , Herman R. L. , Vincx M.
Published: October 2008

Meiofauna from 20 stations (ranging between 8 and 550 m) in the Magellan Straits and the Beagle Channel revealed 28 small sized taxa of higher categories including the temporary meiofauna. Nematoda, Copepoda Harpacticoidea and Polychaeta occurred in all samples; Turbellaria, Bivalvia, Kinorhyncha and Ostracoda were regularly present. Nematodes represented between 68% and 94% of the meiofauna at each station, followed by the copepods (2.3% to 14.5%) and polychaetes (1.1% to 11.5%). Maximal total density, 9700 individuals 10 cm-2, was found in the surroundings of Picton Island, while the mean abundance per station was 3374 individuals 10 cm-2. The vertical pattern within the sediment showed that 87% of meiofauna components concentrated in the upper 0-5 cm sediment layers and 13% in the lower ( > 5cm) layers. More than 95% of copepods, as well as the temporary meiofauna occurred in the top 5 cm layers. The proportion of nematodes and copepods shows opposite trends in the vertical distribution. Multivariate analysis using the total density and the 10 `true´ meiofauna taxa densities discriminates between communities in the Straits of Magellan and the Beagle Channel area. Meiofaunal density was much higher in the Beagle Channel, but the diversity was lower than that in the Straits of Magellan. The Southern Magellan meiofauna communities are compared with those found at the Antarctic Peninsula and in the Weddell Sea (high Antarctic). It is considered that hydrodynamic features (tidal currents with strong winds), geographical characteristics, together with sediment composition are the key parameters structuring the meiofauna community in the Straits of Magellan and in the Beagle Channel.
Sublittoral Harpacticoida (Crustacea, Copepoda) from the Magellan Straits and the Beagle Channel (Chile). Preliminary results of abundance and generic diversity
Authors: George Kai Horst , Schminke Horst Kurt
Published: October 2008

Samples of meiofauna were collected with a Multicorer during the Magellan `Victor Hensen´ Campaign of RV `Victor Hensen´ in 1994 at 62 stations along the Magellan Straits and the Beagle Channel. Seventeen samples were analysed in the framework of a larger project. Only 69 species of Harpacticoida are known from Chile so far, all of them inhabiting the littoral zone. The Magellan Campaign of RV `Victor Hensen´ provided the first opportunity to obtain sublittoral samples of meiobenthos of Chilean coasts. In these samples the Copepoda were represented by 4 of its orders: Calanoida, Cyclopoida, Poecilostomatoida and Harpacticoida, the latter exhibiting the highest abundances. Representatives of 19 harpacticoid families (6 of which are new for Chilean waters) were identified in the samples. The species found in 15 of these families belong to 28 genera of which 18 are new to the Chilean fauna. With respect to taxa composition and distribution, the following preliminary results can be presented: the number of new families and new genera for the southern tip of South America increased considerably; a relatively high similarity between the Magellan Straits/Beagle Channel and areas of corresponding northern latitudes can be observed; the Magellan Straits and Beagle Channel show considerable differences with respect to taxa composition and diversity of the harpacticoid fauna.
State of knowledge of the Corallinales (Rhodophyta) of Tierra del Fuego and the Antarctic Peninsula
Authors: Mendoza María Laura
Published: October 2008

Corallinales (Rhodophyta) in Tierra del Fuego are abundant, with 9 genera, 17 species and 1 subspecies. Pseudolithophyllum with 1 species (P. fueguianum), which represents 35.8% of the coralline algae, is dominant. The genera Parahydrolithon with 4 species (P. consociatum, P. discoideum, P. falklandicum, P. subantarcticum) and 20%, Lithothamnion with 3 species (Lt. heterocladum, Lt. rugosum, Lt. granuliferum) and 17.5%, and Synarthrophyton with 3 species (S. neglectum, S. patena, S. schmitzii) and 12% share are abundant. Clathromorphum with 4 species (Cl. annulatum, Cl. lemoineanum, Cl. obtectulum, Cl. Variabile) and a share of 5.8%, and Mesophyllum with 1 species (M. fueguianum) and a share of 4.9% are frequent. The remaining three genera, Bossiella with 1 subspecies (B. orbigniana ssp. orbigniana), Corallina with 2 species (C. elongata, C. officinalis) (1.1%), and Titanoderna with 1 species (T. conspectum) (1%) are scarce. C. officinalis is a cosmopolitan, and the other geniculate corallines are found in both hemispheres, whereas the crustose coralline occur only in the southern hemisphere. The characteristic vertical distribution of the species in the intertidal and subtidal zone of Tierra del Fuego is given. The Corallinales in the Antarctic Region are poorly known and need further investigation.
Distribution patterns of macrozoobenthos: a comparison between the Magellan Region and the Weddell Sea (Antarctic)
Authors: Gerdes D. , Montiel A.
Published: October 2008

The Joint Chilean-German-Italian Magellan Victor Hensen Campaign in October/November 1994 and the Polarstern expedition ANT XIII/4 (May 1996) yielded 207 quantitative multibox corer samples from 11 stations in the Paso Ancho (Magellan Straits), 10 stations in the Beagle Channel, and 15 stations of the shelf and continental slope off the eastern entrance of the Beagle Channel. Mean abundance values in the Magellan Region varied from 1591 Ind. M-2 in the Paso Ancho to 3643 Ind. m-2 in the Beagle Channel and 3983 Ind. m-2 on the shelf; the corresponding biomass values were 96.8 g, 301.6 g, and 119.0 g wet weight m-2 respectively. In terms of org. C the corresponding values are 4.8, 11.4, and 4.6 g m-2. Abundance (3806 Ind. m-2) and biomass (222.6 g wet weight m-2 or 7.3 g C) data from the eastern Weddell Sea shelf (Polarstern expeditions ANT VI/3, 1987/88 and ANT VII/4, 1989) are in the same range. The composition of the fauna, however, reveals distinct differences.
Taxonomical and biogeographical notes on the sponges of the Strait of Magellan
Authors: Pansini Maurizio , Sará Michele
Published: October 2008

The sponge material from the Straits of Magellan collected by the research vessels Cariboo in 1991 and Victor Hensen in 1994, and by a shallow water diving team, were studied. Most of the investigated bottoms were soft or detritic and true rocky shores were seldom surveyed. However, alternative hard substrata are the holdfasts of dead laminarians, very abundant in the Straits, which represent a sort of microenvironment suitable for settling of sponges and other benthic organisms. Out of a total of more than 150 specimens, 44 demosponge species were identified. The resulting taxonomic pattern suggests a very heterogeneous sponge assemblage, partly related to the variety of the surveyed stations. Sponge communities are characterized by a patchy distribution, a high specific diversity and a low biomass. Most of the recorded species are of austral origin and distribution, confirming the Subantarctic character of the demosponge fauna of the Magellan Straits and its close affinity (14 species in common) with the fauna of the Antarctic continent. Twenty species identified in this study had never been recorded before from the Straits.
Faunal diversity of the benthic amphipods (Crustacea) of the Magellan region as compared to the Antarctic (preliminary results)
Authors: De Broyer Claude , Rauschert Martin
Published: October 2008

To investigate the marine benthic ecosystems of the Magellan region and to compare them with the better known Antarctic systems, three campaigns were recently carried out in this area: the Joint Magellan Victor Hensen Campaign 1994, the Polarstern ANT XIII/4 cruise 1996, and the Vidal Gormaz CIMAR FIORDO II cruise 1996. Numerous and diverse zoobenthos samples were collected mostly with an Agassiz trawl and with a small dredge, an epibenthic sledge, with baited traps or by diving. All gears together gathered more than 132,000 specimens of gammaridean and caprellidean amphipods. 137 species of gammaridean amphipods have been identified from the material to date. About 20% of these species appear to be new for science. This taxonomic work takes place in the framework of a general revision of the Southern Ocean amphipod fauna undertaken by theAntarctic Amphipodologists Network. A complete list of the benthic species of gammaridean and caprellidean amphipods is presented, including the zoogeographical distribution and the new records. The new abundant material collected, still under study, will allow a comparison of faunal diversity, zoogeographical and ecological traits of the Magellan benthic amphipod taxocoenoses with those of the West and East Antarctic benthos.
On the biogeography of Cumacea (Crustacea, Malacostraca). A comparison between South America, the Subantarctic Islands and Antarctica: present state of the art
Authors: Mühlenhardt-Siegel Ute
Published: October 2008

Cumacea (Crustacea) were collected during the Joint Magellan expedition in November 1994, by means of an epibenthic sledge from RV Victor Hensen. The cumaceans were well represented, the second abundant order after the amphipods, among the other Peracarida in depth ranges between 25 and 665 m. Twenty-five species were found in the samples mainly from the Beagle Channel, nine of them were already known for this region. 14 species were recorded for the first time for this region, 2 of them were known from the northern Argentinian coast and one from Antarctica. The most important in terms of species richness and abundance were the families Diastylidae, Nannastacidae and Leuconidae. In the Beagle Channel an almost completely different cumacean fauna was found compared to the Subantarctic Islands, the Antarctic Peninsula and eastern Antarctic (Prydz Bay) regions. Comparison of published data and the present results show moderate overlap in the cumacean fauna at the species level between the periantarctic South Georgian shelf / Antarctic Peninsula (48%). Little correspondence at the species level was found between Antarctica / Subantarctic Kerguelen (14 %), South Georgia / Kerguelen (13 %) and Magellan / Antarctica (11 %). Interestingly, the Magellan region and South Georgia show very little species overlap (5 %). It is concluded that the Antarctic shelf regions were not colonized from the Magellan region via the Scotia Arc.
New localities for Crustacea Decapoda in the Magellan region, southern South America
Authors: Vinuesa Julio H. , Lovrich Gustavo A. , Tapella Federico
Published: October 2008

We report the occurrence of Lithodes turkayi (Anomura), Libidoclaea granaria, and C. edwardsii (Brachyura), in the Beagle Channel. This observation extends their range of distribution south of the previously reported limit of the Straits of Magellan. Acanthocyclus albatrossis (Brachyura) occurs south of Isla Navarino and also in the Beagle Channel, however in a particular habitat of its northern coast. The occurrence of Lithodes confundens (formerly identified as L. antarcticus) north of the eastern entrance of the Straits of Magellan is also reported. We extend its range of distribution northerly and its bathymetric distribution to the intertidal.
Egg production of Austropandalus grayi (Decapoda, Caridea, Pandalidae) from the Magellan Region, South America
Authors: Wehrtmann Ingo S. , Lardies Marco A.
Published: October 2008

Austropandalus grayi is one of three pandalid shrimp species reported from Chilean waters. Here we describe fecundity, reproductive output, and chemical composition of the incubated embryos of A. grayi, providing the first account of such information for a pandalid species inhabiting the southern hemisphere. Ovigerous females (n = 96) were collected during October - November 1994 with an Agassiz trawl in waters off Patagonia and Tierra del Fuego, South America. Both egg production (between 50 and 1858 embryos) and early egg volume (x- = 0.069 mm3) of A. grayi were low when compared to values reported from other pandalids. Clutch size increased with maternal size, however, the size of recently-spawned eggs was not linked to female size. Although the egg mass volume remained almost stable during the incubation period, females lost on average 51.1% of their initially-laid embryos; however, this loss was more than compensated by an 88.4% increase of the egg volume during embryogenesis. Mean reproductive output was relatively low (0.133) and not related to maternal size. The RO-data of A. grayi and other pandalids seem to indicate an increasing energy allocation for reproduction towards higher latitudes, a trend which would be contrary to the results of studies with other crustaceans. Water was the predominant constituent of the chemical composition of developing embryos and increased from 62.2% to 70.2% during the incubation period. At the same time, organic matter declined and mineral content augmented. Generally, our results are in agreement with previous findings with regard to the chemical composition of developing decapod embryos.
Size structure and sex composition of Eurypodius latreillii Guérin, 1828 (Brachyura) and Pagurus comptus White, 1847 (Anomura) in southern Chile
Authors: Soto R. , Quiroga E. , Vargas M. , Navarrete N.
Published: October 2008

The decapod crustaceans Eurypodius latreillii (Brachyura) and Pagurus comptus (Paguridae) were the most frequently occurring species in Agassiz trawl (AGT) samples obtained during the Chilean - German - Italian Victor Hensen Expedition in the Straits of Magellan and south of the Beagle Channel. Sex composition and length structure aspects were studied using the material from 15 stations in the two areas, which comprised 773 specimens of E. latreillii and 647 P. comptus. The size frequency of both species was characterized by the presence of small individuals in shallow waters. The sex composition varied with depth, indicating a dominance of E. latreillii females in deep waters, whereas no such pattern was observed in P. comptus. These differences may be caused by epizoites of E. latreillii and the availability of vacant gastropod shells for P. comptus, in addition to geographical aspects and life-cycle patterns of these species
Feeding habits of the false southern king crab Paralomis granulosa (Lithodidae) in the Beagle Channel, Tierra del Fuego, Argentina
Authors: Comoglio Laura Inés , Amin Oscar Antonio
Published: October 2008

Stomach contents of 282 false southern king crabs (Paralomis granulosa), between 10 to 90 mm CL from the Beagle Channel (Golondrina Bay and Roca Mora), Argentina, were examined by the frequency of occurrence method of analysis and by a food index. Roca Mora is an area where juveniles (< 50 mm CL) dominate and in Golondrina Bay adults (> 60 mm CL) are common; in this last area sexual segregation was also observed. The principal food groups for crabs of Golondrina Bay were algae, molluscs, crustaceans, bryozoans and foraminiferans; for crabs from Roca Mora the natural diet consisted of three major food groups: hydrozoans, echinoderms and foraminiferans. The relative frequency of different prey groups varied in relation to the size, season and sex. There were no significant differences in the quantity of food consumed by sexes in both areas. Generally small crabs (< 40 mm CL) contained more food than large crabs (> 50 mm CL). Juveniles consumed a greater amount of food during winter and spring. In summer (moulting period), juveniles had the highest vacuity index. Adults consumed minor amounts of food during autumn, before the spawning-moulting-mating period when the vacuity index was higher (spring).
On the biogeography and ecology of the Southern Ocean decapod fauna
Authors: Gorny Matthias
Published: October 2008

The biogeography and ecology of decapod crustaceans was described for the higher latitudes of the Southern Ocean. The analyzed area included the transitional or antiboreal region of the South American continental shelves (south of about 42°30'S), the Antarctic continental shelves, the Subantarctic islands of the Scotia and the Kerguelen Arcs, the deep sea south of about 42°S and the pelagic realm between the Subtropical Convergence and the Antarctic continent. A broad base of own data and a review of the literature revealed the presence of 98 benthic decapod species in the entire area, with 92 species on the continental shelves and around the Subantarctic islands, and 6 species in the deep sea. A total of 34 decapod species live in the pelagic system south of the Subtropical Convergence. About 50 % of the benthic species, nearly all deep-sea species, but only one pelagic decapod are endemic in the analyzed sectors of the Southern Ocean. Eualus kinzeri (Caridea: Hippolytidae) is the only endemic decapod of the Antarctic continental shelves. By means of a multivariate cluster analysis the antiboreal decapod fauna of South America was separated from the species living around Antarctica and the Subantarctic islands of the Scotia and Kerguelen Arc. In contrast to earlier studies the northern distribution limit of the Antarctic decapod fauna was set at approximately 55°30'S, and includes species which are distributed on the southern tip of South America. The species number in the antiboreal region of South America is 79, and higher than known before. The caridean shrimps are the most numerous group within the entire area, and together with the anomuran crabs, the palinuran and astacuran lobsters they demonstrate a high degree of eurybathy compared to the Brachyura. The restriction of the Brachyura to shallow-water zones is discussed as one reason, that caused the absence of this group on the Antarctic continental shelves after the successive elimination of the shallow-water fauna during glaciation of the southern hemisphere.
Reproductive biology of the limpet Nacella (P.) deaurata (Gmelin, 1791) in Bahía Lapataia (Beagle Channel)
Authors: Morriconi Elba
Published: October 2008

The reproductive cycle of a Nacella (P.) deaurata population that inhabits the lower intertidal zone in Lapa-taia Bay (54°52´S; 68°29´W) was studied. Monthly samples were collected, and specimens were measured and weighed, fixing the gonads in Bouin´s fluid for histological analyses. The gonadosomatic index (GSI) was determined as a percentage of the ratio between gonadal and foot wet weight. Taking into account the presence and abundance of different cellular types, gonadal stages were established for males and females. The analyses of the variation of the gonadal stage percentages showed the first mature males and females in July. In 1989, mature females maintained a percentage higher than 30% until January. Spawning began in September and was massive in November. In 1990, the maximum percentage of mature females was found in September with all the specimens spawned in October. Nevertheless, the majority of the population was mature again in November. The male sexual cycle in 1989 showed the highest percentage of mature individuals in August, being high until October and slightly diminishing in November. The highest percentage of evacuated males was observed in November-December. In 1990, the cycle was similar to the one shown by the females, but without recovery in November. The GSI variability in males and females, and the adequate use of the GSI in determining the annual reproductive cycle were discussed. The biotic and environmental conditions that may act as a trigger for the spawning have been analyzed.
Ophiuroids (Echinodermata) of southern Chile and the Antarctic: taxonomy, biomass, diet and growth of dominant species
Authors: Dahm Corinna
Published: October 2008

This study aims on a first comparison of the shallow water (< 550 m) ophiuroid fauna of the Magellan region and the high-Antarctic Weddell Sea. Five species are common to both the Magellan region (22 species) and the Weddell Sea (42 species). The most abundant Magellan species is Ophiuroglypha lymani, contributing 33% to total ophiuroid abundance and 44% to total ophiuroid biomass. The diets of O. lymani and of three closely related (same sub-family Ophiurinae) also dominant, Antarctic species are similar, indicate however slightly different feeding strategies. The Magellan species tends more towards microphageous grazing, whereas the Weddell Sea species act more like scavengers. Within the sub-family Ophiurinae growth performance of O. lymani is higher than in Antarctic species and in the range of boreal species.
Short-term changes in the plankton of a highly homogeneous Basin of the Straits of Magellan (Paso Ancho) during spring 1994
Authors: Antezana Tarcisio , Hamamé Madeleine
Published: October 2008

Changes in nutrients, chlorophyll and zooplankton were followed for 11 d in a basin of the Straits of Magellan (Paso Ancho), characterized by a homogeneous water column during a spring event defined by a drastic change in wind stress and direction. Conditions hardly seemed conducive to a phytoplankton bloom. Initial conditions were characterized by SW gales, low nutrients as well as by Chaetoceros spp. and Thalassiosira spp. dominated phytoplankton. Wind switched abruptly to calm-weak northerlies by the middle of the study period, a subsurface chlorophyll peak developed and extended to the end of the study while nitrates decreased. Zooplankton was dominated by copepods, nauplii and a diverse meroplankton assemblage. Zooplankton composition was rather uniform, except for diel changes in some taxa. Gut contents of zooplankton size fractions (including Euphausia vallentini as the largest fraction) were measured. Grazing rates accounted for 0.5 % of the available chlorophyll. Phytoplankton blooming may be explained by transient water stratification resulting from the relaxation of wind stress and eventual retention of the phytoplankton in the photic layer. Minor variability in zooplankton implied the existence of a permanent and distinct assemblage in a strongly homogeneous environment.
Sarsia marii n. sp. (Hydrozoa, Anthomedusae) and the use of 16S rDNA sequences for unpuzzling systematic relationships in Hydrozoa
Authors: Schierwater Bernd , Ender Andrea
Published: October 2008

A new hydrozoan species, Sarsia marii, is described by using morphological and molecular characters. Both morphological and 16S rDNA data place the new species together with other Sarsia species near the base of a clade that developed, walking tentacles in the medusa stage. The molecular data also suggest that the family Cladonematidae (Cladonema, Eleutheria, Staurocladia) is monophyletic. The taxonomic embedding of Sarsia marii n. sp. demonstrates the usefulness of 16S rDNA sequences for reconstructing phylogenetic relationships in Hydrozoa.
Cnidarian Parasites on Solmissus incisa, a Narcomedusa
Authors: Alexandra Osborn Dawn
Published: October 2008

A narcomedusa, Solmissus incisa, was collected off central California in the Monterey Submarine Canyon at 230 m in October 1996. The medusa was viewed and collected from the RV Point Lobos using the remotely operated vehicle (ROV) Ventana. Advantages of such in situ observation include the ability to recognize parasites (which appear as small, opaque circles) on the bell of the specimen. In the laboratory, the circular objects were found to be parasitic, cnidarian-like juveniles developing within the epidermis, stages that moved freely, extending and retracting their tentacles. It is not known whether these juveniles are true parasites - i.e. juveniles of another species drawing nutrition from the host medusa, or whether they are offspring being brooded. Solmissus is one of the most numerous genera of medusae in Monterey Bay, and this is the first report of parasites on members of that genus in the California Current system
Photosynthetic planulae and planktonic hydroids: contrasting strategies of propagule survival
Authors: Pagliara Patrizia , Bouillon Jean , Boero Ferdinando
Published: October 2008

Settlement delays can be important to prevent propagule waste when proper settling substrates are not immediately available. Under laboratory conditions, the planulae of Clytia viridicans underwent two alternative developmental patterns. Some settled on the bottom, forming a hydranth-gonotheca complex that produced up to four medusae and later either degenerated or gave rise to a hydroid colony. Other planulae settled right below the air-water interface, forming floating colonies that eventually fell to the bottom and settled. Halecium nanum released planulae with a rich population of symbiotic zooxanthellae that survived into a rearing jar for three months. After a long period of apparent quiescence (possibly fuelled by photosynthetic activities of zooxanthellae) the planulae produced new colonies. Both photosynthetic planulae and settlement at the interface air-water allow a delay in the passage from a planktonic to a fully functional benthic life.
The hydroid and medusa of Sarsia bella sp. nov. (Hydrozoa, Anthoathecatae, Corynidae), with a correction of the life cycle of Polyorchis penicillatus (Eschscholtz)
Authors: Brinckmann-Voss Anita
Published: October 2008

A new hydrozoan, Sarsia bella sp. nov. is described in both its hydroid and medusa stage from north of Puget Sound, Washington in the San Juan Islands, USA and off the southernmost tip of Vancouver Island, Canada. The medusa is distinguished from other Sarsia species by 16 exumbrellar nematocyst patches and in being more transparent or glass like when living than any other known species of the genus. The exumbrellar nematocyst patches become indistinct in mature specimens and in those crowded in culture, with single nematocysts increasingly spaced out. The hydroid, both field-collected and raised in culture from its medusa, forms small, upright stolonal colonies not more than 1.5 mm high. The hydranths bear an oral whorl of four to five capitate tentacles, and immediately below a second whorl of slightly shorter capitate tentacles. In thriving colonies there is occasionally a whorl of small filiform tentacles on the lower part of the hydranth. Medusa buds develop in the middle of hydranth below the capitate tentacles and above the reduced filiform tentacles, if present. Young medusae are liberated with the typical 16 exumbrellar nematocyst patches. The hydroid of this species was originally mistaken for the hydroid of Polyorchis penicillatus. Brinckmann-Voss (1977) reported a small corynid hydroid living on the margin of rock scallop shells. Medusae liberated from this hydroid were at that time believed to be those of Polyorchis penicillatus (Eschscholtz) present in the plankton. Immature medusae of these two species appear strikingly similar, especially with regard to their exumbrellar nematocyst patches, four tentacles and abaxial ocelli. Since then however, this connection has been proven wrong, because an identical hydroid was raised from the medusae of the new species Sarsia bella. Second generation medusae raised in the laboratory were carefully compared with medusae liberated from field collected hydroids (thought to have been Polyorchis penicillatus), and these were found to be identical with meduse of Sarsia bella. Young medusae of P. penicillatus from the plankton can be clearly distinguished from S. bella medusae by the number of their exumbrellar nematocyst patches. Both P. penicillatus and Sarsia bella have eight adradial rows of exumbrellar nematocyst patches when young, however each row in P. penicillatus consists of at least three vertically alligned patches whereas each row never has more than two patches in S. bella. In both species the patches consist of microbasic p-mastigophores, but capsules in the case of P. penicillatus are larger than those in S. bella. Later stages of the two species are easily distinguished using other morphological characters with only four tentacles in S. bella and more than four in P. penicillatus. No hydroid of the genus Polyorchis has been described to date.
Ecological characteristics of the Mljet Islands seawater lakes (South Adriatic Sea) with special reference to their resident populations of medusae
Authors: Benovic A. , Lucic D. , Onofri V. , Pehardia M. , Caric M. , Jasprica N. , Bobanovic-Colic S.
Published: October 2008

Ecological properties and distribution and abundance of medusae were studied over an 18-month period in the Mljet Island seawater lakes, south-east Croatia. Strong stratification during the summer differentiates these lakes from the oligotrophic South Adriatic ecosystem. The lakes are designated as a moderately eutrophicated ecosystem. Very small numbers of hydromedusae were noted, representing only the Anthomedusae and Leptomedusae. A new species of the genus Tima was found in considerable numbers of individuals. High abundance of the scyphomedusa Aurelia sp. was observed throughout the year. This species differs in terms of genetic divergence from Aurelia aurita found elsewhere in the Mediterranean and could be attributed to the boreal origin.
A new species of Pachycordyle (Hydrozoa, Clavidae) from Lake Biwa (Japan), with remarks on this and related Clavid genera
Authors: Stepanjants Sofia D. , Timoshkin Oleg A. , Anokhin Boris A. , Napara Tatiana O.
Published: October 2008

The history of research on species of Pachycordyle and related genera is discussed. A description and differential diagnosis of a new species, Pachycordyle kubotai, is presented. Hydroid colonies, hydranths, and gonophores of this species are described in detail. Peculiarities of medusoid development and oocyte maturation are analyzed. The genus Pachycordyle is rediagnosed and an identification key to species assigned to it is provided. Clavopsella is regarded as congeneric with Pachycordyle. Thieliana is established as a new genus for species subsequently and erroneously assigned to Clavopsella. The taxonomic status of species referable to Thieliana is discussed. Justification is provided for our position that these genera belong to the family Clavidae. Characteristics of genera assigned to the family Clavidae are summarized. Data on the geographic distribution and ecology of the species of Cordylophora, Pachycordyle, and Thieliana, referred here to the subfamily Cordylophorinae, are presented.