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Mar del Plata, Argentina

Lazo D.G.,Institute Estudios Andinos Don Pablo Groeber | Damborenea S.E.,Museo de Ciencias Naturales de La Plata
Journal of Paleontology | Year: 2011

The Cretaceous Huitrín Formation in west-central Argentina records the final connection of the Neuquén Basin to the Pacific Ocean. This formation is comprised of a variety of continental to marginal-marine sediments deposited behind an Andean volcanic arc under warm, arid paleoclimatic conditions. Here we focus on a bivalve fauna from carbonate ramp deposits within the Barremian La Tosca Member of the Huitrín Formation. This fauna is very abundant and widely distributed within the basin but, surprisingly, it has not yet been studied in detail. In addition, paleoenvironmental affinities remain unresolved, with the fauna variously interpreted as having freshwater, brackish, and marine affinities. We studied the fauna's taxonomy and paleoecology based on more than 500 specimens collected at ten fossil localities in combination with new field observations. The bivalve assemblage was recorded from middle to outer carbonate ramp deposits and is composed of five taxa of marine affinity: Phelopteria huitriniana n. sp., Isognomon cf. I. nanus (Behrendsen), Placunopsis? pichi n. sp., Anthonya jarai n. sp., and Argenticyprina mulensis n. gen. n. sp.; the first three may be regarded as eurytopic and/or opportunistic. Reduced diversity, low evenness, overall small size (length <4 cm), thin shells, eurytopic or opportunistic life strategies, and high endemism point to a restricted marine setting for the La Tosca Member. The most important limiting factors likely were low primary productivity and fluctuating salinity and temperature, as conditions inferred for the unit include high evaporation rates combined with low continental runoff and reduced rainfall. Thick evaporite deposits below and above La Tosca Member and thin intercalated gypsum beds support a restricted, hypersaline setting. © 2011 The Paleontological Society. Source

Pinilla K.,Museo de Ciencias Naturales de La Plata
Revue de Paleobiologie | Year: 2012

In Argentina, the genus Ananias Knight (Gastropoda, Eotomariidae) is known from the Calingasta-Uspallata Basin in San Juan and Mendoza Provinces, and, also, from the Tepuel Genoa Basin (Chubut Province). Material from the last region was described in open nomenclature during the 1970's and since then it has not been taxonomically revised. The new species Ananias riccardii from the Cisuralian (Callitomaria tepuelensis - Streblochondria sp. Zone) of the Tepuel Genoa Basin is described herein. The new taxon is characterized by having a phaneromphalous, moderately-large, gradate and high-spired shell, a concave selenizone, an ornamentation consisting of nodose spiral lirae and growth lines, and fine spiral threads at the base. Source

Anenterotrema liliputianum (Travassos, 1928) (Anenterotrematidae) is redescribed based on the type specimens from Molossus molossus (Pallas) and Phyllostomus elongatus (Geoffroy) from Brazil, and also on new specimens collected from the Dwarf Dog-faced Bat, Molossops temminckii (Burmeister) (Molossidae) in Argentina. In addition, we report the finding of Gymnoacetabulum talaveraensis (Lunaschi, 2002), Ochoterenatrema labda Caballero, 1943 (Lecithodendriidae), and Urotrema scabridum Braum, 1900 (Urotrematidae) parasitizing Vespertilionidae and Molossidae bats from Buenos Aires and Misiones provinces, and measurements, prevalence, and mean intensity for these trematodes are provided. In addition, the host spectrum and distribution for A. liliputianum and O. labda is increased, and U. scabridum is recorded for the first time parasitizing bats in Argentina. Source

Carpintero D.L.,Museo Argentino de Ciencias Naturales Bernardino Rivadavia | Carpintero D.L.,CONICET | Dellape P.M.,Museo de Ciencias Naturales de La Plata | Dellape P.M.,CONICET
Acta Entomologica Musei Nationalis Pragae | Year: 2012

The tribe Scolopini is characterized by having males with uradenia consisting of paired glands with either a single or paired openings on abdominal sternum III or IV (exceptionally on V), and females with copulatory tubes (not in Calliodina), and by a midventral abdominal copulatory site. The tribe is composed of two subtribes, Scolopina with four genera and Calliodina with seven genera. Two new genera of Scolopini are proposed: Guayascoris foreroi, a new genus and species of Calliodina from Ecuador, and Ameroscolopa, a new genus of Scolopina including the two American species of Scoloposcelis Fieber, 1864: Ameroscolopa flavicornis (Reuter, 1871) comb. nov. and A. basilicus (Drake & Harris, 1926) comb. nov. Diagnostic characters, geographic distribution, species included, and a key to all Neotropical genera of the tribe are also given. Source

Piovesan E.K.,University of the Rio dos Sinos Valley | Ballent S.,Museo de Ciencias Naturales de La Plata | Fauth G.,University of the Rio dos Sinos Valley
Cretaceous Research | Year: 2012

Majungaella is a survivor genus of a long lineage of the family Progonocytheridae, ranging from the Jurassic to the Pliocene. In this paper new species from Argentina and Brazil are described and appropriately illustrated, comprising a systematic review of 16 species, including two new ones. The Jurassic and Early Cretaceous species seem to have inhabited mainly shallow, warm waters, whereas from the mid-Late Cretaceous and especially in the Cenozoic, a retrothermal propensity is observed in the genus. The records of . Majungaella are revised and its distribution is used to demonstrate the prior juxtaposition of subsequently separated Gondwana continental blocks and the opening of new seaways. The data have allowed a deeper understanding of the depositional sequences and supplied information on the early geological history and subsequent palaeoceanographic evolution of the South Atlantic Ocean. The affinities of the ostracod faunas from South America and other gondwanan localities are used to analyze the evolution of seaways and oceanic barriers. © 2012 Elsevier Ltd. Source

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