Potential invasion of the Atlantic coast of South America by Semimytilus algosus (Gould, 1850)

The mytilid Semimytilus algosus (Gould, 1850) was collected from a fishing vessel after an in-water hull cleaning operation at Nuevo Gulf, north Patagonia, Argentina. This species is native to the Pacific coast of South America and had not been detected on the Atlantic coast of this continent. Histological slides from male and female portions of gonads of a subsample of specimens showed spawning activity. The gonad stages observed were: developing stage, ready to spawn, spawning, or had already spawned, suggesting the possibility of establishment of a breeding population in the area. The water temperatures, its seasonal range, and the habitats occupied by S. algosus in its native area are very similar to those present in Nuevo Gulf. The plasticity of this species, and its rapid invasion in other regions of the world, suggest that it could become a new invasive species in the Southwestern Atlantic in the near future. Targeted monitoring of the rocky shores of Nuevo Gulf is recommended to determine whether this non-native species is at an early stage of becoming established.Fil: Bigatti, Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Schwindt, Evangelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentin

Naticid boreholes on a tertiary cylichnid gastropod from southern Patagonia

The fossil communities are in clear disadvantage when it comes to study the interactions among the species included in them. However, predation on shells gives us the possibility to examine at least some of these interactions. The diameter of the borehole, its placement, and the volume of the prey are parameters that can be easily recorded. Diverse combinations of these may allow inference about the size of the predator and the time spent on the perforation (Kitchell et al., 1981).Fil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Pastorino, Roberto Santiago Guido. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Griffin, Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales; Argentin

Presencia de Pteria colymbus (Bivalvia: Pteriidae) en aguas argentinas

The family Pteriidae is well represented in tropical and subtropical continental shelf regions. Two na- mes belonging to the genus Pteria are usually recorded in the literature from the southwestern Atlantic: P. colym- bus (Röding) and P. hirundo (Linnaeus). The study of living specimens sampled off Buenos Aires coast aboard of the R/V Puerto Deseado allows updating the geographic range of the Atlantic wing oyster Pteria colymbus in the region. Type materials of related species are illustrated. Ecological requirements and shell morphology descrip- tion of P. colymbus are provided. This study constitutes the first revision of this species from Argentine waters.La familia Pteriidae se encuentra bien representada en áreas tropicales y subtropicales. A lo largo del océano Atlántico sudoccidental, dos nombres pertenecientes al género Pteria han sido citados en la bibliografía. Estos son: P. colymbus (Röding) y P. hirundo (Linnaeus). El estudio de nuevos ejemplares vivos recolectados frente a las costas de Buenos Aires a bordo del BO Puerto Deseado permitió actualizar el rango de distribución geográfica de la especie Pteria colym- bus. Adicionalmente se ilustró el material tipo de las especies nominales relacionadas. Se relevaron los requisitos ecológicos y se describió la morfología de la concha de P. colymbus. Este estudio constituye la primera revisión de esta especie en aguas argentinas.Fil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; ArgentinaFil: Pastorino, Roberto Santiago Guido. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; Argentin

Marine invertebrate and seaweed biodiversity of continental coastal Ecuador

This study summarises the diversity of living macroinvertebrates and seaweeds from the intertidal and subtidal rocky shores along Ecuadorian continental coast. Benthic macroinvertebrate communities and seaweeds were quantified over quadrants (50 × 50 cm) randomly placed on transects of 50 m length. A checklist of 612 species was generated: 479 species of macroinvertebrates and 133 species of seaweeds. Groups recorded were Mollusca (184 species), Cnidaria (70), Arthropoda (68), Annelida (60), Echinodermata (42), Chordata (18), Bryozoa (13), Porifera (22), Sipuncula (2), Brachiopoda and Platyhelminthes (only identified as morphotypes). The seaweeds were represented by Rhodophyta (78), Chlorophyta (37), Ochrophyta (13), Cyanobacteria (5) and 19 biotic complexes. Furthermore, 22 new taxa and six alien species were recorded from the intertidal zone. This study provides the first large scale report of benthic communities in different marine coastal ecosystems in mainland Ecuador, covering 1,478 km2 of protected areas and 382 km2 of non-protected areas. The highest benthic diversity was registered in the protected areas and rocky shores from the intertidal zone. The biological data, herein reported, are useful for a long-term monitoring programme to evaluate the status of conservation and to detect rapid changes in the benthic biodiversity from coastal areas.Fil: Cárdenas Calle, Maritza. División Ambiental. Bioelite, Guayaquil; Ecuador. Universidad de Guayaquil. Ciudadela Universitaria; EcuadorFil: Mora, Elba. División Ambiental. Bioelite, Guayaquil; EcuadorFil: Torres, Genoveva. Universidad de Guayaquil. Ciudadela Universitaria; EcuadorFil: Pérez Correa, Julián. Universidad Espíritu Santo; EcuadorFil: Bigatti, Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Coronel, Jorge. Universidad Agraria del Ecuador; Ecuado

The Family Mactridae Lamarck, 1809 (Bivalvia: Cardiida) in South African Waters

The species belonging to the family Mactridae living in South African waters are revised. After a bibliographical research, almost forty nominal species were found related to this area. The type material of all taxa was requested, examined and illustrated whenever possible. Additional comparative specimens from Natal Museum were studied. Details of type localities, repositories, and updated distribution were provided. This work revealed the presence of nine species belonging to the family Mactridae living in South African waters: Mactra aequisulcata G. B. Sowerby III, 1894, Mactra lilacea Lamarck, 1818, Simomactra capensis (G. B. Sowerby III, 1892), Scissodesma spengleri (Linnaeus, 1767), Standella ovalina (Lamarck, 1818), Lutraria (Lutraria) capensis Reeve, 1854, Lutraria (Lutraria) steynlussii Huber, 2010a, Lutraria (Psammophila) inhacaensis Boshoff, 1965, and Eastonia solanderi (Gray, 1837). However, their generic placement, in some cases, must be confirmed. Genetic data will clarify if two new generic names for Mactra aequisulcata and Simomactra capensis, respectively, are required.Fil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentin

The molluscan genera Mactrella and Mactrinula: Taxonomic revision and redescription of type species

The genera Mactrella and Mactrinula, both described by Gray in 1853, have generally been considered synonyms. Additionally, five species had been included in Mactrella were later placed in the genus Mactrellona Marks, 1951. The diagnosis of type species of these genera, as well as the study of their type material, have clarified the taxonomic status of the three related genera. The genus Micromactra Dall, 1894, is added to the synonymy of Mactrella. The complete shell morphology of type species Mactrella striatula and Mactrinula plicataria, both introduced by Linnaeus, 1767, is described. An updated synonymy list of each species is provided. In addition, an expanded geographical distribution of the genus Mactrella is given. Illustrations of Mactrellona alata (Spengler, 1802), Mactrellona exoleta (Gray, 1837), Mactrellona clisia (Dall, 1915), Mactrella californica (Conrad, 1837), Harvella elegans (G. B. Sowerby I, 1825), and Mactrella janeiroensis (E. A. Smith, 1915) are included.Fil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

Moluscos bivalvos en los inexplorados abismos suratlánticos

Los fondos marinos, en particular los más profundos, se cuentan entre las áreas menos exploradas de nuestro planeta. Las especies de seres vivos que habitan esos ambientes exhiben características únicas y plantean a los científicos el desafío de comprender su biología. ¿Cómo puede alimentarse un organismo sin luz, sin oxígeno y sometido a una presión decenas o centenas de veces mayor de la que impera en la superficie?Fil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentin

The Superfamily Mactroidea (Mollusca:Bivalvia) in American Waters

In this catalogue, the valid species belonging to the superfamily Mactroidea living in American waters are recognized. In the study area the family Mactridae, includes 12 genera and 48 species distributed in three subfamilies (Mactrinae, Lutrariinae and Darininae). There are Ten genera belonging to the subfamily Mactrinae living in American waters. They are Harvella, Mactrellona, Mactromeris, Mulinia, Rangia, Simomactra, Spisula, Standella, Trinitasia and Tumbeziconcha. Lutrariinae is only represented by the genus Tresus and includes three valid species living in the north western cost of North America. On the other hand, the subfamily Darininae is represented by the genus Darina with two valid species living in the southern tip of South America. The family Anatinellidae is represented by two genera with two valid species each one, all included into the subfamily Kymatoxinae. Finally, the family Mesodesmatidae is represented in American waters by the genus Mesodesma with 3 valid species and the recently described Amarilladesma with only one species.Fil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentin

Mactra guidoi n. sp. and Mactra patagonica (Bivalvia: Mactridae), two long misunderstood species from Southwestern Atlantic Ocean

A common mactrid from the southwestern Atlantic Ocean has been largely misunderstood in the literature. Since the early 20th century, this species has been referred to as Mactra patagonica d'Orbigny, 1846. However, the latter is recorded in Quaternary deposits of Northern Patagonia. Mactra guidoi n. sp. is described herein, including its shell ultrastructure, hinge features, and soft parts, and compared with the holotype of M. patagonica. To compare and to correctly identify both species, a morphometric analysis was carried out using conventional and geometric morphometric methods. Mactra guidoi n. sp. has an elongate shell that is more fragile than that of M. patagonica. In addition, its ventral posterior edge is usually sinuous. The ultrastructure of the shell reveals two layers with cross lamellar structure. The anatomical features agree with those of the congeneric M. isabelleana, although they differ in the morphology of the labial palps and foot. Morphometric analysis revealed significant differences between M. patagonica and the new species. The relative warp analysis allows us to understand the variation recognized by using CVA. Only M. patagonica revealed significant allometry between Relative Warp and Centroid size. Finally, the comparison of the types clearly points towards the existence of two different species.Fil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Scarabino, Fabrizio. Museo Nacional de Historia Natural y Antropologia; Urugua

Taxonomic revision of living boring bivalves belonging to the family Pholadidae Lamarck, 1809, (Bivalvia: Myida) from South western Atlantic

Boring bivalves of the family Pholadidae Lamarck, 1809 living in Argentinean and Uruguayan waters are herein revised. The literature research revealed twelve nominal species of Pholadidae mentioned as living in the study area. Type material of all nominal taxa were examined when it was possible. Additional specimens from field works and malacological collections were studied, illustrated and re-described. Details of type localities, repositories, and distribution range are provided for each valid taxa. This work revealed the presence of five native and one introduced species belonging to Pholadidae in Argentinean and Uruguayan waters. Barnea (Anchomasa) lamellosa, Cyrtopleura (Scobinopholas) lanceolata, Pholas (Thovana) campechiensis and Martesia fragilis belonging to the Argentine biogeographical province; Netastoma darwinii from Magellan province; and Barnea (Anchomasa) truncata introduced in the Bahía Blanca estuary. Finally, morphological comparison with congeneric species distributed in American seas are provided.Fil: Delfino, Marina Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentin