Unravelling the identity of Pandora species (Bivalvia: Pandoridae) from Southern South America

Four species of Pandora have been reported from southern South America: P. cistula Gould, 1850, P. braziliensis G. B. Sowerby II, 1874, P. diffissa Mabille & Rochebrune, 1889 and P. patagonica (Dall, 1915). The group has received little taxonomic attention in this area, resulting in arbitrary and wrong usage of these names, for which several contradictory synonymies have been proposed. This study provides the first revision of Pandora species living in southern South America, including photographs of the type material and descriptions of shells, gross anatomy and living animals. Out of the four species previously mentioned, P. braziliensis is here regarded as valid, including P. patagonica and P. diffissa as synonyms. The fourth species, P. cistula, remains known only from its type specimen. In addition, a new species, P. brevirostris, is described from the shallow waters of Argentina.Fil: Güller, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: Zelaya, Diego Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentin

The smallest marine bivalves from the end of the world (Tierra del Fuego, Isla de Los Estados and Burdwood Bank)

Small molluscs are known to be particularly abundant towards the poles. Although recent studies on sub-Antarctic waters of the southernmost tip of South America have begun to show a highly diversified small-sized fauna, micromolluscs have not yet received sufficient attention. Recently, samplings targeting the smallest molluscan benthic fauna have been conducted in the sub-Antarctic waters of South America, providing material of three new minute species occurring in The End of the World (Tierra del Fuego, Isla de los Estados and Burdwood Bank). The present study describes Pachykellya fuegiensis n.sp. (Neoleptonidae), Benthocardiella ituartei n.sp. and Benthocardiella finisterra n.sp. (Condylocardiidae). These are not only the smallest bivalves currently known from the area, but are also smaller than any other species thus far known from the adjacent Antarctic waters, and are included among the smallest species of their respective genera. To confirm generic placement, the type species of Pachykellya (P. edwardsi F.B. Bernard 1897) and Benthocardiella (B. pusilla Powell 1930) are studied for the first time with scanning electron microscopy. This study allows to amend the previous descriptions of hinge teeth number, morphology and arrangement for these genera. Based on these new findings, Pachykellya and Benthocardiella are here reported for the first time in South America.Fil: Güller, Marina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Zelaya, Diego Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

The families carditidae and condylocardiidae in the magellan and Perú-Chile provinces (bivalvia: Carditoidea)

Based on the study of available types and extant collections, this paper provides a systematic revision of the living species of Carditoidea occurring in the Magellan and Perú-Chile Provinces. Out of the 19 nominal species reported for the area, eight species are recognized as valid: Cyclocardia compressa, C. spurca, C. thouarsii, C. velutina, Carditella naviformis,C. semen, C. tegulata and Carditopsis flabellum. Other eight nominal species are regarded as synonyms: Cardita magellanica of Cyclocardia velutina; Carditella pallida of C. tegulata; Cardita australis and Actinobolus philippi of Carditella naviformis; Cardium pygmaeum of Carditella semen; Cardita paeteliana of Cyclocardia spurca; Carditella pallida duodecimcostata of Carditopsis flabellum; and Cardita congelascens of Cyclocardia thouarsii. Furthermore, Cardita malvinae and Cardium parvulum are nomina dubia, and the occurrence of Carditella exulata in Magellanic waters is doubtful.Fil: Güller, Marina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Zelaya, Diego Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Filling a blank in bivalve taxonomy: an integrative analysis of Cyamioidea (Mollusca: Bivalvia)

This contribution provides the first integrative study of Cyamioidea, a group of bivalves largely neglected in the past.By combining information obtained from shell morphology, gross anatomy, histology, reproductive biology and DNAsequencing, the distinctive characters of Cyamioidea are determined, and the taxa belonging to this superfamily are revised. Gaimardioidea, previously considered as a distinct superfamily, is reduced to family level (Gaimardiidae),which, along with Cyamiidae, are assigned to Cyamioidea. All studied cyamioideans share a common reproductive character: the presence of a true follicular epithelium surrounding each developing oocyte, which persists afterspawning, surrounding the developing embryos and participating in their anchorage to the gill filaments. Several morphological and anatomical characters support the distinction of Gaimardiidae and Cyamiidae. Based on thatinformation, the placement of Gaimardia and Kidderia in Gaimardiidae, and that of Cyamiocardium, Cyamiomactra, Cyamium, Heteromactra, Pseudokelly, Ptychocardia and Reloncavia in Cyamiidae, is confirmed. Jukesena, historicallyplaced in Veneroidea, is here allocated to Cyamiidae. Neoleptonidae, previously also attributed to Cyamioidea, are reallocated to Veneroidea.Fil: Zelaya, Diego Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Güller, Marina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ituarte, Cristian Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

A hot-spot of biodiversity in Northern Patagonia, Argentina

Located along the Argentine coastline of northern Patagonia, are San Matías (SMG) and San José (SJG) gulfs; although they are regarded as an area with a high-priority conservational status, knowledge on their diversity is currently fragmentary. Studies on molluscs from this area have been historically centred in economic resources and few works have referred to non-commercial species. The present study aims to document the biological diversity of molluscs at the SMG/SJG area, in order to determine the significance of these two gulfs in the context of the Argentine marine fauna; to evaluate how well represented is this fauna in three protected areas; and to compare the fauna present in the protected areas with that of a non-protected area. For that purpose, molluscs coming from 132 sampling stations, ranging from the intertidal to 170 m depth, were studied, and a thorough bibliographic compilation was performed. A total of 196 species of molluscs are reported for the area. Surprisingly, almost one third of these species lacked previous records for SMG/SJG, including several new/possibly new species. The three studied protected areas contain 88.3% of the species recognised for the entire SMG/SJG area. Although several species appear as exclusive from one of these three areas, many of them are also present in an intermediately located, non-protected area. Molluscan diversity at the SMG/SJG area is greater than previously thought, comprising about 41.4% of the bivalves and 37.8% of the gastropods present in the Argentine shelf; thus suggesting that the area may be considered as a hot-spot of diversity in the Argentine Sea.Fil: Güller, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Zelaya, Diego Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Bivalvia

El presente capítulo provee una síntesis sobre aspectos morfológicos, anatómicos, biológicos y biogeográficos de los moluscos bivalvos, incluyendo una síntesis sobre su clasificación actual y la diversidad del grupo en el Mar Argentino.Fil: Zelaya, Diego Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Güller, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Species of Iothia (Gastropoda: Lepetidae) from Shallow Waters of the Magellan Region

The Lepetidae are currently assumed to be represented by only one valid species in the Magellan region: Iothia emarginuloides (Philippi, 1868), of which Tectura (Pilidium) coppingeri Smith, 1881, and Iothia coppingeri magellanica Linse, 2002, were regarded as synonyms. The extant records of this species are scarce, although they suggest a wide distributional range in the Pacific Ocean, from off Concepción (36°S) to the Beagle Channel (55°S), and a restricted distribution in the Atlantic Ocean, where the species is only known from the Malvinas / FalklandIslands and Isla de los Estados (about 54.5°S). This study provides new information on the occurrence of the genus Iothia in the Magellan region, including morphological, anatomical and molecular evidence. The synonymy of Tectura (Pilidium) coppingeri, Iothia coppingeri magellanica and Iothia emarginuloides is ratified. The species is properly redescribed and figured, and its intraspecific variability discussed, particularly regarding its relation with depths. Furthermore, the distribution of this species in the southwestern Atlantic is extended north to San Matías Gulf (about 41°S). Iothia megalodon Warén, Nakano & Sellanes, 2011, previously known from deep waters off Concepción (36°S), is here reported for the first time for the Magellan region. Its finding in shallow waters from the Beagle Channel greatly extends its distribution both latitudinally and bathymetrically.Fil: Güller, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; ArgentinaFil: Zelaya, Diego Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

New insigths into the diversity of rissoids from sub-antarctic and antarctic waters (Gastropoda: Rissooidea)

Molluscs have been regarded as one of the most extensively studied and better known marine invertebrates groups in sub-Antarctic and Antarctic benthic communities. In order to test this statement we address here the study of some species of the caenogastropod family Rissoidae, collected during several expeditions to Tierra del Fuego and the Scotia Arc. Currently, the local diversity of this family accounts for a total of 30 species, which were thoroughly revised mostly as part of two monographs. The present study provides new information on shell morphology, radulae and distribution for four of these species: Onoba fuegoensis (Strebel, 1908), O. delecta Ponder, 1983, O. klausgrohi Engl, 2011 and Haurakia averni Ponder and Worsfold, 1994; also contributes to a better understanding of the intraspecific variability of two other species: Onoba schythei (Philippi, 1868) and O. algida Ponder and Worsfold, 1994; and seven new species are described: Onoba clara, O. sandwichensis, O. verrucosa, O. antleri, O. caribu, O. oligochordata, and O. ernestoi. These new findings not only contribute to increase the number of species currently known from the studied area, and provide the first record of a species with multispiral protoconch, and the first record of a bathyal species from southern South America. Furthermore, as part of this study the presence of ?antler-like? marginal teeth is reported for two species, a condition thus far not reported for any other Rissoidae. This study highlights that, even being one of the most intensively studied marine invertebrate groups, molluscs from the Sub-Antarctic and Antarctic waters still remain scarcely known.Fil: Güller, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Zelaya, Diego Gabriel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Revision of Pyramidellidae (Gastropoda: Heterobranchia) from Argentina triples their diversity in northern Patagonia

During an intensive sampling of the molluscan fauna from San Matías Gulf, northern Patagonia, Pyramidellidae were the most diverse family and one of the most abundant. This is in contrast with previous literature, in which only seven species have been mentioned from the area. Here we revise the species collected in this area and, in the light of this information, provide a reassessment of the diversity of this group in Argentina. We recognize 24 pyramidellid species, belonging to the genera Boonea, Fargoa, Peristichia, Careliopsis, Turbonilla, Eulimastoma, Ondina and Odostomia s. l. New distributional ranges for Peristichia lepta, Careliopsis bahiensis, Turbonilla farinatiae, T. zulmae, T. rushii, Eulimastoma franklini and Odostomia puelchana are given. A neotype is designated for Turbonilla sanmatiensis. The status of the type material of T. uruguayensis and Boonea multituberculata is clarified, and the latter species is redescribed and figured. In addition, nine new species are described, five of them comprising specimens that had previously been misidentified. The presence of eight other species, previously regarded as distributed from the Caribbean or Floridean Provinces to Argentina is here questioned. As a result of this study, a total of 28 valid species of pyramidellids are currently recognized from Argentina.Fil: Güller, Marina. 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 Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Zelaya, Diego Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentin

On the generic allocation of "Aligena" Pisum dall, 1908

Aligena pisum Dall, 1908 is currently only known from the original description. The species was reported either under the lasaeid genus Aligena or the thyasirid genus Axinulus, and also regarded as a nomen dubium. Based on the re-examination of the holotype and the study of additional specimens from the Magellan Strait, Beagle Channel, and Southern Chile, the species is redescribed, properly illustrated, and its generic placement revised. The morphological and anatomical characters studied here reveal that the species is actually a thyasirid, and the presence of granules at the hinge plate is the main character supporting the reallocation of this species into the genus Adontorhina. The present finding provides the first record of Adontorhina in the Southern hemisphere.Fil: Güller, Marina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; ArgentinaFil: Zelaya, Diego Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División de Zoología Invertebrados; Argentin