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

Assemblages of certain benthic molluscs along the southwestern Atlantic: From subtidal to deep sea

Background: We analyse the distribution of Gastropods and Chitons from shallow to deep waters along the southwestern Atlantic Ocean off Argentina and discuss possible factors determining the observed biogeographic patterns. Results: Three major biogeographic groups are defined on the basis of Gastropod and Chiton species associations, i.e., continental shelf ( 350-2000 m) and lower continental slope (2000-3000 m). Bathymetry appears as the main factor modifying large-scale distribution of the fauna at a. In this scenario, species associations are determined by marine currents that clearly occur at a particular and well defined depth. No arrangement of species by geographic location was found in assemblages from the continental shelf and upper continental slope. Conclusions: We hypothesize that depth and marine currents are the main factor affecting the distribution of Gastropods and Chitons along the SW Atlantic between 200 and 3000 m depth.Fil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Urteaga, Diego Gaston. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; 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"; Argentin

¿Pueden los pastoreadores nativos de Patagonia, Argentina, consumir al alga invasora Undaria pinnatifida?

El alga invasora Undaria pinnatifida (Phaeophyceae, Laminariales) fue reportada por primera vez en Golfo Nuevo en 1992, dispersándose ampliamente a lo largo de 170 km de costa en el norte de la Patagonia, Argentina. Observaciones de campo hechas en los erizos de mar Arbacia dufresnii y Pseudechinus magellanicus y en el gasterópodo Tegula patagonica evidenciaron que son posibles consumidores de Undaria pinnatifida en la población local. Se realizaron experimentos de laboratorio con el objetivo de probar si estos pastoreadores eran capaces de consumir el alga. Los erizos de mar estudiados consumen el alga, mientras que el gasterópodo ramonea los epibiontes presentes sobre su superficie. Altas densidades de ramoneadores fueron encontradas sobre el alga durante el verano y podrían ser atribuidas a un aumento del su metabolismo con el aumento de la temperatura y a la degradación de las láminas y esporofilos, lo cual posiblemente aumente la palatabilidad del alga.The invasive kelp Undaria pinnatifida (Phaeophyceae, Laminariales) was first reported in Golfo Nuevo in 1992 and since then it has spread widely over more than 170 km, all along the northern Patagonian coast, Argentina. Field observations in the region have indicated the potential role of invertebrate grazers, like the sea urchins Arbacia dufresnii and Pseudechinus magellanicus and the gastropod Tegula patagonica, in controlling algal density. Laboratory experiments were conducted to ascertain whether, and if so, to what extent these grazers actually feed on the algae. The studied sea urchins fed on the alga, whereas the snail scraped off biofouling adhered to its surface. Higher densities of grazers were observed on the kelp during summer and might be attributed to increasing in metabolism with increasing temperature, and degradation of blades and sporophylls, which possibly increase their palatability.Fil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Bigatti, Gregorio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Casas, Graciela Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Piriz, Maria Luz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentin

Growing up in the deep-sea protected development in deep-sea invertebrates: A case study in the southwestern Atlantic Ocean

Marine invertebrates display a range of reproductive strategies, from external fertilization to several methods to protect the young. Both brooding or protected development of benthic species and direct development species (when juveniles born in a smaller version of its adult form) involves reducing the time that the larvae and/or juveniles spend in the plankton. The different forms of juvenile protection are often associated with the taxonomic group, although certain groups are much diversified in terms of their reproductive modes. However, the area where the species live also seems to play a key role. Several authors have indicated the unusual proportion of brooding species in the Southern Ocean, in particular in the southwestern Atlantic, including its adjacent deep-sea. The knowledge about the reproductive characteristics of most of the fauna in this area remains unknown. Proof of this are the great number of studies carried out in recent years, describing the reproductive features of several species (many also new), with some of them having many peculiarities about their biology.Fil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Martinez, Mariano Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Lauretta, Daniel Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; 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: Urteaga, Diego Gaston. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Averbuj, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Brogger, Martin Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; ArgentinaFil: Arrighetti, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Rivadeneira, Pamela Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Flores, Jonathan Nahuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Pertossi, Renata Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Sánchez, Noelia Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Pacheco, Leonel Ivan. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Di Luca, Javier Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Sanchez Antelo, Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Risaro, Jessica Ayelen. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Ciocco, Rocio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Reproductive cycle in an imposex-affected population of Olivancillaria deshayesiana (Gastropoda: Olividae) from Mar del Plata, Argentina

Olivancillaria deshayesiana (Gastropoda: Olividae) is distributed from Ilha Grande (Rio de Janeiro, Brazil) to Necochea (Buenos Aires, Argentina). Apart from some descriptions of the embryonic development and the egg capsules, little is known about the reproduction and ecology of this species. In this 2 yr study (October 2005 to September 2007), the reproductive cycle of O. deshayesiana was examined in a population highly affected by imposex, from the Mar del Plata coast, Argentina. Males exhibited seasonal reproductive activity, with a major spawning period from September to January (spring to early summer) for the 2 yr, which coincided with an increase in seawater temperature and photoperiod. In contrast, females were mature and capable of spawning year round, with a major spawning period from September to January (spring to summer), simultaneous with the major spawning period of males.Fil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Arrighetti, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biología Experimental. Laboratorio de Biología de Invertebrados Marinos; ArgentinaFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Sperm morphology of two species of Olivancillaria (Gastropoda: Olividae) from the south-western Atlantic

Sperm ultrastructure in two species of the marine snail family Olividae is examined. Euspermatozoa of both species are com- posed of a conical, membrane-bound acrosomal vesicle; an axial rod and a basal plate similar in both species; a solid and highly electron-dense nucleus; an elongate midpiece consisting of the axoneme sheathed by helical mitochondrial elements; an elongate glycogen piece; a double electron-dense ring at the junction of the midpiece and glycogen piece; and a free tail region. The slight narrowing in the acrosomal vesicle invagination is situated in different levels between Olivancillaria deshayesiana and Olivancillaria carcellesi. This morphology could be considered as a specific character. The length of the nucleus in O. carcellesi and in O. deshayesiana is shorter than that of other neogastropods, and could be diagnostic at family level.Fil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; ArgentinaFil: Giménez, Juliana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biologia Experimental y Aplicada; Argentin

Development of the gastropod Trochita pileus (Calyptraeidae) in the sub-Antarctic Southwestern Atlantic

The family Calyptraeidae is widely distributed around the world and shows several types of development all with physical care. Adults and broods of Trochita pileus from sub-Antarctic waters were collected during two cruises off Tierra del Fuego and Burdwood Bank at depths between 39 and 298 m. A total of 43 brooding females and 314 egg capsules of T. pileus were collected. Shell diameter of brooding females ranged from 12.6 to 28.8 mm. The egg capsules were flattened triangular sacs with rounded vertices and lateral margins longer than the distal margin. The number of egg capsules per brood increased significantly with increasing shell diameter of brooding females from 1 to 15 and a mean number of 7.9 ± 2.8. T. pileus has direct development from embryos which start consuming nurse eggs (oophagy) and then continue eating developing embryos (adelphophagy). The 80.7% of the initial eggs of T. pileus did not initiate development. From about 1000 initial uncleaved eggs per egg capsule (diameter around 250 µm), only 8 complete their development hatching as crawling juveniles. The observation of the post-gastrula stage of T. pileus swallowing all nurse eggs and latter also other embryos in the same stage of development is the first case of oophagy and adelphophagy in the genus Trochita. No late intracapsular cannibalism has been observed. To our knowledge, there are no records of Antarctic Calyptraeidae and this would be the development of one of the southernmost species described.Fil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentin

Beach filling and imposex in Olivancillaria deshayesiana (Mollusca: Gastropoda: Olividae) from the coast of Mar del Plata, Argentina

Beach filling activities were conducted along the Mar del Plata coastline, Argentina, with sediments dredged from the harbour mouth between November 1998 and April 1999. We determined the percentage of imposex of Olivancillaria deshayesiana before, during and immediately after beach filling. The current situation (2005 –2007) of imposex incidence was compared between populations from Mar del Plata and Mar Chiquita, a less impacted area. In addition, we evaluated differences in shell shape and body weight between females with and without imposex. The percentage of imposex was significantly higher during (85.3%) and after (73.9%) beach filling than before it (31.0%). No differences in body weight were found in the female population but shell length was significantly lower in females with imposex. As expected, the Mar Chiquita population showed no signs of imposex. This is the first report of imposex in beaches nourished with sand dredged from the port. Our results highlight the importance of analysing more carefully the sediment before beach filling. On the basis of the high level of imposex recorded near the port of Mar del Plata, O. deshayesiana can be used as a biological indicator of marine contamination with butyltin compoundsFil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

A revision of the genus Olivancillaria (Mollusca: Olividae) from the southwestern Atlantic

The genus Olivancillaria is revised and restricted to eight living species: O.deshayesiana, O. carcellesi, O. urceus, O. contortuplicata, O. orbignyi, O. teaguei, O.auricularia and O. vesica. The last two species were previously considered assubspecies. The name O. uretai is a junior synonym of O. orbignyi. The genusOlivancillaria is endemic to the Southwestern Atlantic with range from Bahia state,Brazil (~12°S) to Chubut province (42°37’S), Argentina, intertidal up to 70 m depth. Itis a clear representative of the Argentine Malacological province. Redescriptions and reillustration of types were done for each species. Shell ultrastructure, radulae, penes,siphon papillae and egg capsules are described and illustrated by SEM images. Ageometric morphometric analysis was carried out to confirm shell variation on size andshape among species. The geographic distribution of each species is provided based onfield observations as well as on museum records.Fil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; 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”; Argentin

The panpulmonate limpet Siphonaria lessonii Blainville, 1827 as a sentinel of contamination in coastal areas of Argentina

Although some studies have evaluated the use of Siphonaria lessonii as a bioindicator of pollution, no study has identified the effects of human activities on the digestive gland, which is the main centre of detoxification of xenobiotics and a target organ in contamination studies. Thus, the present work aims to evaluate the use of this species as a suitable sentinel of contamination by analysing the digestive gland and shell alterations. The study was carried out in three populations exposed to different degrees of anthropogenic impact in the coast of Buenos Aires: a reference site (VG), a mid-impacted site (MPL) and a highly-impacted site (MPP). A histological analysis of the digestive gland was performed, as well as an assessment of the geometric morphometry, thickness, density and microstructure of the shell. Our results indicated that the individuals from the impacted sites present several histological alterations in the tubules of the digestive gland. These included hypertrophy and hyperplasia of different cell types (MPP), alterations of the digestive tube morphology (MPL and MPP), the presence of lipofuscin-like substances (MPL) and a high inflammatory response (MPP). In the shells, neither microstructural malformations nor changes in the elemental composition were found. However, shell morphometric variations and a decrease in shell hardness (thickness and density) were observed in the impacted sites. In conclusion, our results indicate that S. lessonii is a well-suited sentinel of contamination since the effects of anthropogenic impact may be reflected in both soft and hard structures. Although further investigations are necessary to identify the relationship between these effects and their potential causing agents, these simple and low-cost methodological approaches could be used to diagnose disturbance in the ecosystem health status where this species inhabits.Fil: Landro, Sonia Maribel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Teso, Silvia Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Arrighetti, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin