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Marcelo S De La Fuente - One of the best experts on this subject based on the ideXlab platform.
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una tortuga chelidae testudines pleurodira de cuello largo en el grupo neuquen rio negro argentina significado cronologico y paleobiogeografico
Andean Geology, 2010Co-Authors: Marcelo S De La Fuente, Ruben Barbieri, Pablo ChafratAbstract:Diferentes restos de una tortuga Chelidae cuellilarga de la Formacion Anacleto (Santoniano tardio-Campaniano temprano), aflorante en la localidad de Valle de la Luna Rojo, Provincia de Rio Negro, Argentina, son conferidos a la especie Yaminuechelys cf. gasparinii De la Fuente, De Lapparent de Broin y Manera de Bianco, 2001. Ellos representan el registro mas antiguo para el genero y los Chelidae de cuello largo. Se sugiere que el ancestro comun de Yaminuechelys e Hydromedusa habito en Gondwana meridional con anterioridad a la separacion de Australia. La presencia de este taxon en el Cretacico Tardio en Patagonia y algunos de los resultados de los analisis filogeneticos previos apoyan la hipotesis sobre una temprana diferenciacion y diversificacion de los quelidos en dicha region de Gondwana.
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Una tortuga Chelidae (Testudines: Pleurodira) de cuello largo en el Grupo Neuquén, Río Negro, Argentina: Significado cronológico y paleobiogeográfico A long-necked Chelidae turtle (Testudines: Pleurodira) from the Neuquén Group, Río Negro, Argentina:
Servicio Nacional de Geología y Minería (SERNAGEOMIN), 2010Co-Authors: Marcelo S De La Fuente, Ruben Barbieri, Pablo ChafratAbstract:Diferentes restos de una tortuga Chelidae cuellilarga de la Formación Anacleto (Santoniano tardío-Campaniano temprano), aflorante en la localidad de Valle de la Luna Rojo, Provincia de Río Negro, Argentina, son conferidos a la especie Yaminuechelys cf. gasparinii De la Fuente, De Lapparent de Broin y Manera de Bianco, 2001. Ellos representan el registro más antiguo para el género y los Chelidae de cuello largo. Se sugiere que el ancestro común de Yaminuechelys e Hydromedusa habitó en Gondwana meridional con anterioridad a la separación de Australia. La presencia de este taxón en el Cretácico Tardío en Patagonia y algunos de los resultados de los análisis filogenéticos previos apoyan la hipótesis sobre una temprana diferenciación y diversificación de los quélidos en dicha región de Gondwana.A long necked chelid turtle species from the Anacleto Formation (late Santonian-early Campanian) cropping out at Valle de La Luna Rojo, Río Negro Province, Argentina, is assigned to Yaminuechelys cf. gasparinii De la Fuente, De Lapparent de Broin and Manera de Bianco, 2001 and it represents the oldest record of a long-necked chelid. We suggest that the common ancestor of Yaminuechelys and Hydromedusa lived in Southern Gondwana before the separation of Australia from the remaining Southern Gondwanan landmasses. The presence of this chelid taxon in the Late Cretaceous of Patagonia and some previous phylogenetic analyses support the hypothesis of an early differentiation and diversification of chelids on Southern Gondwana
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una nueva especie del genero Hydromedusa wagler pleurodira chelidae del paleogeno de patagonia
Ameghiniana, 2002Co-Authors: Marcelo S De La Fuente, Paula BonaAbstract:A new species of the side-necked turtle referred to the genus Hydromedusa Wagler is described on isolated shell fragments discovered from a horizon of Canadon Hondo Formation (lower Eocene) outcropping in eastern-central Patagonia. The holotype consists in a nuchal bone with a cervical (= extravertebral) scute recessed from the anterior margin of the carapace an autopornorhic condition present in the extant species of Hydromedusa. Several characters present in this extinct species (such as the wide first vertebral scute extended on the postero-Iateral extremities of the first peripheral bone, the proportion an position of the twelf marginal scales, the femoral/anal scales radio) suggest a specific differentiation from the extant species. The assignation of isolated fragments of the peripheral bones from Salamanca Forrnation (lower Paleocene) to the genus Hydromedusa extends in 10 m.a. the record of this genus in South America.
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the oldest and first nearly complete skeleton of a chelid of the Hydromedusa sub group chelidae pleurodira from the upper cretaceous of patagonia
Bulletin De La Societe Geologique De France, 2001Co-Authors: Marcelo S De La Fuente, Teresa Manera De BiancoAbstract:A new pleurodiran (side necked) turtle is described on material from the Upper Cretaceous of Patagonia, from sediments outcropping at Cerro Blanco, Yaminue Creek, Rio Negro, Argentina. The sediments are compared to those from the Pellegrini lake area referred to the middle Member of the Allen Formation, Upper Campanian-Lower Maastrichtian. Yaminuechelys gasparinii n.g., n.sp., is a pleurodiran turtle on the pelvis sutured to the shell and a chelid on the formula of cervical vertebrae and the lateral cheek emargination, deeply extended towards (as here) or up to the posterior emargination. It is the oldest record of a nearly complete skeleton of a chelid, long necked (elongated cervical vertebrae, lowered skull), and the first sufficiently known of the Chelodina-Hydromedusa group (elongated skull, lowered neural arch and centrum of the cervicals, low zygapophyses processes, strong polygoned decoration) and of the Hydromedusa sub-group (widened inner nares by reduced palatine ossification). The carapace is 41,8 cm long. It is more primitive than Hydromedusa (Eocene-Extant, South America) and retains primitive characters either still present or no more present in the other chelids of the Pseudemydura, Emydura and Phrynops groups (short necked) and Chelus group (long necked), representing the anterior clades of phyletic diversification [Gaffney, 1977], or evolutive grades, of the family. Such are plesiomorphic, relative to Hydromedusa, the less pronounced lateral skull emargination, wider and longer hyoid elements, wider nucal and cervical, this not drawn back, presence of lateral mesoplastra, not shortened bridge, straight borders of the not shortened and not widened posterior plastral lobe, amphicoelous sacrals and caudal vertebrae uniting amphicoelous, concavoplaty--(i.e. anteriorly concave, posteriorly flat) and procoelous or weakly procoelous elements. As Hydromedusa, Yaminuechelys n. g. retains primitive characters such as the long series of neurals, the very lateral attachment of the axillar and inguinal processes and the attachment of the pelvis, below pleural 8 (and 7 in the extant form) and a small part of the suprapygal, and the ischitatic sutures prolonged on the xiphiplastral points. It is distinguished by the apomorphic presence of a wide and week anterior carapacial notch. Yaminuechelys n.g., or aff. Yaminuechelys spp. are known in Patagonia by fragmentary remains in a dozen of Upper Cretaceous and two Palaeocene localities. Before them, chelids are known in the world only by undefined smaller forms from Lower Albian and Upper Albian-Cenomanian Patagonian localities. In Australia, they are known from Palaeocene-Lower Eocene (no Cretaceous data before) with already extant Australian diversified forms. Yaminuechelys n.g. demonstrates how long the diversification in chelids is realized in South Gondwana before the full break of the continents.
Pablo Chafrat - One of the best experts on this subject based on the ideXlab platform.
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una tortuga chelidae testudines pleurodira de cuello largo en el grupo neuquen rio negro argentina significado cronologico y paleobiogeografico
Andean Geology, 2010Co-Authors: Marcelo S De La Fuente, Ruben Barbieri, Pablo ChafratAbstract:Diferentes restos de una tortuga Chelidae cuellilarga de la Formacion Anacleto (Santoniano tardio-Campaniano temprano), aflorante en la localidad de Valle de la Luna Rojo, Provincia de Rio Negro, Argentina, son conferidos a la especie Yaminuechelys cf. gasparinii De la Fuente, De Lapparent de Broin y Manera de Bianco, 2001. Ellos representan el registro mas antiguo para el genero y los Chelidae de cuello largo. Se sugiere que el ancestro comun de Yaminuechelys e Hydromedusa habito en Gondwana meridional con anterioridad a la separacion de Australia. La presencia de este taxon en el Cretacico Tardio en Patagonia y algunos de los resultados de los analisis filogeneticos previos apoyan la hipotesis sobre una temprana diferenciacion y diversificacion de los quelidos en dicha region de Gondwana.
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Una tortuga Chelidae (Testudines: Pleurodira) de cuello largo en el Grupo Neuquén, Río Negro, Argentina: Significado cronológico y paleobiogeográfico A long-necked Chelidae turtle (Testudines: Pleurodira) from the Neuquén Group, Río Negro, Argentina:
Servicio Nacional de Geología y Minería (SERNAGEOMIN), 2010Co-Authors: Marcelo S De La Fuente, Ruben Barbieri, Pablo ChafratAbstract:Diferentes restos de una tortuga Chelidae cuellilarga de la Formación Anacleto (Santoniano tardío-Campaniano temprano), aflorante en la localidad de Valle de la Luna Rojo, Provincia de Río Negro, Argentina, son conferidos a la especie Yaminuechelys cf. gasparinii De la Fuente, De Lapparent de Broin y Manera de Bianco, 2001. Ellos representan el registro más antiguo para el género y los Chelidae de cuello largo. Se sugiere que el ancestro común de Yaminuechelys e Hydromedusa habitó en Gondwana meridional con anterioridad a la separación de Australia. La presencia de este taxón en el Cretácico Tardío en Patagonia y algunos de los resultados de los análisis filogenéticos previos apoyan la hipótesis sobre una temprana diferenciación y diversificación de los quélidos en dicha región de Gondwana.A long necked chelid turtle species from the Anacleto Formation (late Santonian-early Campanian) cropping out at Valle de La Luna Rojo, Río Negro Province, Argentina, is assigned to Yaminuechelys cf. gasparinii De la Fuente, De Lapparent de Broin and Manera de Bianco, 2001 and it represents the oldest record of a long-necked chelid. We suggest that the common ancestor of Yaminuechelys and Hydromedusa lived in Southern Gondwana before the separation of Australia from the remaining Southern Gondwanan landmasses. The presence of this chelid taxon in the Late Cretaceous of Patagonia and some previous phylogenetic analyses support the hypothesis of an early differentiation and diversification of chelids on Southern Gondwana
Gili, J.m. Maria) - One of the best experts on this subject based on the ideXlab platform.
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Alta heterogeneidad espacial de dos especies de cnidarios planctónicos en relación a la variabilidad a corta escala temporal de un frente plataforma-talud
'Editorial CSIC', 2017Co-Authors: Guerrero Elena, Sabatés Ana, Orejas Covadonga, Marrodán Pellicer Anna, Gili, J.m. Maria)Abstract:11 pages, 6 figures, 4 tables.-- This study is a contribution of the Marine Biodiversity Conservation Group (MEDRECOVER) 2014SGR-1297 and the Ecology of Marine Communities Group (2014SGR-1364) at the Institut de Ciències del Mar-CSIC[EN] We investigated the variability in the mesoscale distribution of the siphonophore Muggiaea atlantica and the Hydromedusa Aglaura hemistoma in relation to the rapid spatial oscillations of the shelf-slope front off the Catalan coast (NW Mediterranean). Three extensive surveys were carried out in spring at ten-day intervals. High variability in the position of the front resulted from the advection of low-salinity waters originating in the Gulf of Lions, mainly from the Rhône River runoff. High spatial variability in the distribution of the two species was closely related to the shifting positions of the front. Both species occurred on its inshore side in much higher abundances than on its offshore side, where they were scarce or absent. The front acts as a barrier limiting offshore displacement of these two cnidarians. Statistical analyses showed that bottom depth and salinity, as independent variables, were indicators of the signature and position of the front, explaining most of the variance in the distribution and abundance of the two species[ES] La variabilidad en la distribución de meso-escala del sifonóforo Muggiaea atlantica y la hidromedusa Aglaura hemistoma se investigó en relación a las rápidas oscilaciones espaciales del frente plataforma-talud en la costa Catalana (Mediterráneo noroccidental). Durante la primavera, se realizaron tres campañas oceanográficas intensivas, distanciadas 10 días entre sí. La alta variabilidad en la posición del frente fue resultado de la advección de aguas de baja salinidad procedentes del Golfo de León, al norte del área de estudio, debido principalmente a los aportes del río Ródano. La alta variabilidad espacial observada en la distribución de las dos especies estuvo muy relacionada con la posición cambiante del frente. Ambas fueron mucho más abundantes en el lado costero que en el lado oceánico del frente, donde éstas fueron muy escasas o incluso ausentes. El frente actúa como una barrera limitando el desplazamiento hacia mar abierto de estos dos cnidarios. Los análisis estadísticos realizados mostraron que la profundidad y salinidad, como variables independientes, fueron indicadoras de la señal y la posición del frente, explicando la mayor parte de la varianza de la distribución y abundancia de ambas especiesThis study was partially supported by the EU Project VECTORS (FP7 OCEAN-2010, 266445) and the Spanish project FISHJELLY (MAR-CTM2010-18875).Peer Reviewe
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Alta heterogeneidad espacial de dos especies de cnidarios planctónicos en relación a la variabilidad a corta escala temporal de un frente plataforma-talud
'Editorial CSIC', 2016Co-Authors: Guerrero E., Marrodán A., Sabatés A., Orejas C., Gili, J.m. Maria)Abstract:We investigated variability in the mesoscale distribution of the siphonophore Muggiaea atlantica and the Hydromedusa Aglaura hemistoma in relation to the rapid spatial oscillations of the shelf-slope front off the Catalan coast (NW Mediterranean). Three extensive surveys were carried out in spring at ten-day intervals. High variability in the position of the front resulted from the advection of low-salinity waters originating in the Gulf of Lions, mainly from the Rhône River runoff. High spatial variability in the distribution of the two species was closely related to the shifting positions of the front. Both species occurred on its inshore side in much higher abundances than on its offshore side, where they were scarce or absent. The front acts as a barrier limiting offshore displacement of these two cnidarians. Statistical analyses showed that bottom depth and salinity, as independent variables, were indicators of the signature and position of the front, explaining most of the variance in the distribution and abundance of the two speciesLa variabilidad en la distribución de meso-escala del sifonóforo Muggiaea atlantica y la hidromedusa Aglaura hemistoma se investigó en relación a las rápidas oscilaciones espaciales del frente plataforma-talud en la costa Catalana (Mediterráneo noroccidental). Durante la primavera, se realizaron tres campañas oceanográficas intensivas, distanciadas 10 días entre sí. La alta variabilidad en la posición del frente fue resultado de la advección de aguas de baja salinidad procedentes del Golfo de León, al norte del área de estudio, debido principalmente a los aportes del río Ródano. La alta variabilidad espacial observada en la distribución de las dos especies estuvo muy relacionada con la posición cambiante del frente. Ambas fueron mucho más abundantes en el lado costero que en el lado oceánico del frente, donde éstas fueron muy escasas o incluso ausentes. El frente actúa como una barrera limitando el desplazamiento hacia mar abierto de estos dos cnidarios. Los análisis estadísticos realizados mostraron que la profundidad y salinidad, como variables independientes, fueron indicadoras de la señal y la posición del frente, explicando la mayor parte de la varianza de la distribución y abundancia de ambas especiesVersión del editor1,006
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Alta heterogeneidad espacial de dos especies de cnidarios planctónicos en relación a la variabilidad a corta escala temporal de un frente plataforma-talud
'Editorial CSIC', 2016Co-Authors: Guerrero Elena, Marrodán Anna, Sabatés Ana, Orejas Covadonga, Gili, J.m. Maria)Abstract:We investigated the variability in the mesoscale distribution of the siphonophore Muggiaea atlantica and the Hydromedusa Aglaura hemistoma in relation to the rapid spatial oscillations of the shelf-slope front off the Catalan coast (NW Mediterranean). Three extensive surveys were carried out in spring at ten-day intervals. High variability in the position of the front resulted from the advection of low-salinity waters originating in the Gulf of Lions, mainly from the Rhône River runoff. High spatial variability in the distribution of the two species was closely related to the shifting positions of the front. Both species occurred on its inshore side in much higher abundances than on its offshore side, where they were scarce or absent. The front acts as a barrier limiting offshore displacement of these two cnidarians. Statistical analyses showed that bottom depth and salinity, as independent variables, were indicators of the signature and position of the front, explaining most of the variance in the distribution and abundance of the two species.La variabilidad en la distribución de meso-escala del sifonóforo Muggiaea atlantica y la hidromedusa Aglaura hemistoma se investigó en relación a las rápidas oscilaciones espaciales del frente plataforma-talud en la costa Catalana (Mediterráneo noroccidental). Durante la primavera, se realizaron tres campañas oceanográficas intensivas, distanciadas 10 días entre sí. La alta variabilidad en la posición del frente fue resultado de la advección de aguas de baja salinidad procedentes del Golfo de León, al norte del área de estudio, debido principalmente a los aportes del río Ródano. La alta variabilidad espacial observada en la distribución de las dos especies estuvo muy relacionada con la posición cambiante del frente. Ambas fueron mucho más abundantes en el lado costero que en el lado oceánico del frente, donde éstas fueron muy escasas o incluso ausentes. El frente actúa como una barrera limitando el desplazamiento hacia mar abierto de estos dos cnidarios. Los análisis estadísticos realizados mostraron que la profundidad y salinidad, como variables independientes, fueron indicadoras de la señal y la posición del frente, explicando la mayor parte de la varianza de la distribución y abundancia de ambas especies
Kamran Mohseni - One of the best experts on this subject based on the ideXlab platform.
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an arbitrary lagrangian eulerian formulation for the numerical simulation of flow patterns generated by the Hydromedusa textit aequorea victoria
arXiv: Fluid Dynamics, 2010Co-Authors: Mehmet Sahin, Kamran MohseniAbstract:A new geometrically conservative arbitrary Lagrangian-Eulerian (ALE) formulation is presented for the moving boundary problems in the swirl-free cylindrical coordinates. The governing equations are multiplied with the radial distance and integrated over arbitrary moving Lagrangian-Eulerian quadrilateral elements. Therefore, the continuity and the geometric conservation equations take very simple form similar to those of the Cartesian coordinates. The continuity equation is satisfied exactly within each element and a special attention is given to satisfy the geometric conservation law (GCL) at the discrete level. The equation of motion of a deforming body is solved in addition to the Navier-Stokes equations in a fully-coupled form. The mesh deformation is achieved by solving the linear elasticity equation at each time level while avoiding remeshing in order to enhance numerical robustness. The resulting algebraic linear systems are solved using an ILU(k) preconditioned GMRES method provided by the PETSc library. The present ALE method is validated for the steady and oscillatory flow around a sphere in a cylindrical tube and applied to the investigation of the flow patterns around a free-swimming Hydromedusa \textit{Aequorea victoria} (crystal jellyfish). The calculations for the Hydromedusa indicate the shed of the opposite signed vortex rings very close to each other and the formation of large induced velocities along the line of interaction while the ring vortices moving away from the Hydromedusa. In addition, the propulsion efficiency of the free-swimming Hydromedusa is computed and its value is compared with values from the literature for several other species. The fluid dynamics video presented here shows the time variation of the instantaneous three-dimensional vorticity isosurfaces around a free-swimming Hydromedusa \textit{Aequorea victoria}.
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an arbitrary lagrangian eulerian formulation for the numerical simulation of flow patterns generated by the Hydromedusa aequorea victoria
Journal of Computational Physics, 2009Co-Authors: Mehmet Sahin, Kamran MohseniAbstract:A new geometrically conservative arbitrary Lagrangian-Eulerian (ALE) formulation is presented for the moving boundary problems in the swirl-free cylindrical coordinates. The governing equations are multiplied with the radial distance and integrated over arbitrary moving Lagrangian-Eulerian quadrilateral elements. Therefore, the continuity and the geometric conservation equations take very simple form similar to those of the Cartesian coordinates. The continuity equation is satisfied exactly within each element and a special attention is given to satisfy the geometric conservation law (GCL) at the discrete level. The equation of motion of a deforming body is solved in addition to the Navier-Stokes equations in a fully-coupled form. The mesh deformation is achieved by solving the linear elasticity equation at each time level while avoiding remeshing in order to enhance numerical robustness. The resulting algebraic linear systems are solved using an ILU(k) preconditioned GMRES method provided by the PETSc library. The present ALE method is validated for the steady and oscillatory flow around a sphere in a cylindrical tube and applied to the investigation of the flow patterns around a free-swimming Hydromedusa Aequorea victoria (crystal jellyfish). The calculations for the Hydromedusa indicate the shed of the opposite signed vortex rings very close to each other and the formation of large induced velocities along the line of interaction while the ring vortices moving away from the Hydromedusa. In addition, the propulsion efficiency of the free-swimming Hydromedusa is computed and its value is compared with values from the literature for several other species.
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flow structures and fluid transport for the Hydromedusa sarsia tubulosa
19th AIAA Computational Fluid Dynamics, 2009Co-Authors: Doug Lipinski, Kamran MohseniAbstract:The flow structures produced by the Hydromedusa Sarsia tubulosa are examined using direct numerical simulation Lagrangian coherent structures (LCS). Sarsia tubulosa uses a jetting type of propulsion, emitting a single strong, fast moving vortex ring during each swimming cycle while a secondary vortex of opposite rotation remains trapped within the subumbrellar region. This secondary vortex has not been observed prior to this study. The ejected vortex is highly energetic and moves away from the Hydromedusa very rapidly. We find that Sarsia tubulosa swims with a Strouhal number of 0.1. This means that vortices produced by Sarsia tubulosa move away from the Hydromedusa at a rate of about 10 diameters per swimming cycle. This presents very little feeding opportunity during swimming for the Hydromedusa. Finally, we examine the pressure on the interior bell surface and the velocity profile in the wake of Sarsia tubulosa. We find that the swimming closely resembles a slug of fluid being shot from the velar opening and might be closely approximated by a slug model. All results are based on numerical simulations of the swimming Hydromedusa. This paper has been prepared for submission to the 19th AIAA Computational Fluid Dynamics conference in the catagory of Lagrangian and vortex methods
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simulation of flow patterns generated by the Hydromedusa aequorea victoria using an arbitrary lagrangian eulerian formulation
Journal of Computational Physics, 2009Co-Authors: Kamran MohseniAbstract:The animation show the three-dimensional vorticity field around a free-swimming Hydromedusa Aequorea victoria (crystal jellyfish).
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The numerical simulation of o w patterns generated by the Hydromedusa Aequorea victoria using an arbitrary Lagrangian-Eulerian formulation
38th Fluid Dynamics Conference and Exhibit, 2008Co-Authors: Mehmet Sahin, Kamran MohseniAbstract:A new geometrically conservative arbitrary Lagrangian-Eulerian (ALE) formulation in the swirl-free cylindrical coordinates has been developed to solve the o w patterns generated by the Hydromedusa Aequorea victoria. The governing equations are multiplied with the radial distance and integrated over arbitrary moving Lagrangian-Eulerian quadrilateral elements. Therefore, the continuity and the geometric conservation equations take very simple form similar to those of the Cartesian coordinates. The continuity equation is satised exactly within each element and a special attention is given to satisfy the geometric conservation law (GCL) at the discrete level. The equation of motion of a deforming body is solved in addition to the Navier-Stokes equations in fully-coupled form. The mesh deformation is achieved by solving the linear elasticity equation at each time level while avoiding remeshing in order to enhance numerical robustness. The resulting algebraic linear systems are solved using an ILU(k) preconditioned GMRES method provided by the PETSc library. The present ALE method is validated for the steady and oscillatory o w around a sphere in a cylindrical tube and applied to the investigation of the o w patterns around a free-swimming Hydromedusa Aequorea victoria (crystal jellysh). The calculations for the Hydromedusa indicate the shed of the opposite signed vortex rings very close to each other and the formation of large induced velocities along the line of interaction while the ring vortices moving away from the Hydromedusa.
Carlos D Perez - One of the best experts on this subject based on the ideXlab platform.
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the non indigenous medusa blackfordia virginica hydrozoa leptothecata in tropical brazil 50 years of unnoticed presence
Biological Invasions, 2014Co-Authors: Milena Freire, Gabriel N. Genzano, Sigrid Neumannleitao, Carlos D PerezAbstract:Blackfordia virginica, a Hydromedusa native to the Black Sea, has become established in a number of estuarine areas worldwide. In estuaries of northeastern Brazil, only a single published report, from the early 1960s, exists of the species and its establishment here has remained doubtful. On discovering specimens collected in the region at various times between 1987 and 2000, however, we hypothesized that this Hydromedusa has long inhabited estuaries in the area while going unnoticed. The objective of this study was to investigate its occurrence in brackish waters of tropical northeastern Brazil over the past 50 years. In a search for specimens we found 1,759 individuals from estuaries of the Santa Cruz Channel (Itamaraca) and Capibaribe and Jiquia rivers that had been collected between 1987 and 2000. In addition, an analysis of grey literature (Ph.D. theses) suggests that the species has been present in the Santa Cruz Channel for at least five decades. Results thus support the hypothesis that this non-indigenous species has been established in the region for several decades at least, and that it constitutes an exotic component of the community.
