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We describe isolated teleostean teeth found in no association with the jaw bone. The specimens have been recovered in Late Cretaceous marine deposits of the Vivian Formation in the Peruvian Sub-Andean Region. The deposition sequence from where the teeth come is interpreted as a shallowing-upward sequence of low salinity. The fish material is identified as Enchodus aff. E. gladiolus based on the presence of a small but well-developed post-apical barb, an anterior cutting edge, the crown is symmetrical in cross-section, have a sigmoidal profile, and bears strong ridges (=striations). The Peruvian material differs from the typical E. gladiolus teeth in having a faintly serrated anterior cutting edge which is absent in most specimens referred to E. gladiolus. We also highlight that taxonomic assignments made based on isolated teeth must be taken with care. Despite scarce, the material recovered denotes that the marine units of Peru can give valuable information about the Pacific fish fauna during the Late Cretaceous.

La familia Chaperiidae alcanza su máxima biodiversidad en el hemisferio sur. El principal rasgo morfológico que caracteriza a la familia es un par de láminas calcáreas asociadas con la inserción de los músculos oclusores del opérculo. El propósito de este trabajo es describir a Aluis spinettai gen. et sp. nov., a partir de material obtenido en las Formaciones Monte León, Chenque y Puesto del Museo (Mioceno temprano, Patagonia, Argentina). A. spinettai posee colonias erectas bilaminares, suturas crenuladas entre los zooides, un extenso criptocisto y ovicelas esféricas, y carece de gimnocisto, espinas orales y avicularias. La nueva especie exhibe una notable convergencia morfológica con una especie del género Aspidostoma del Mioceno temprano (Fm. Chenque) en Patagonia. En algunas zonas de la colonia los zooides presentaban perforaciones circulares en el criptocisto realizadas por un depredador desconocido. A. spinettai presenta una distribución estratigráfica que va desde ~19 a 17 Ma (Burdigaliano). Su presencia sugiere una correlación entre los niveles superiores de la Formación Monte León y los inferiores de la Formación Chenque. La distribución paleogeográfica de esta nueva especie abarca al menos 500 km a lo largo de la costa atlántica austral de Sudamérica. Los representantes actuales de la familia Chaperiidae en el Atlántico Sudoccidental no parecen relacionados con A. spinetta. The family Chaperiidae reaches its highest biodiversity in the southern hemisphere. The main morphological feature characterizing the family is a pair of calcareous laminar structures associated with the insertion of the operculum occlusor muscles. The aim of this study is to describe Aluis spinettai gen. et sp. nov., from material collected in the Monte León, the Chenque, and the Puesto del Museo formations (early Miocene, Patagonia, Argentina). A. spinettai has erect bilaminar colonies, crenulated sutures between zooids, an extensive cryptocyst and spherical ovicells; gymnocyst, oral spines, and avicularia are absent. The new species exhibits a remarkable morphological convergence with a species of Aspidostoma from the early Miocene (Chenque Formation) of Patagonia. In some areas of the colony, the cryptocysts were pierced by circular drill holes made by an unknown predator. The stratigraphic distribution of A. spinettai ranges from â19 to 17 Ma (Burdigalian). Its presence suggests a correlation between the upper levels of the Monte León Formation and the lower levels of the Chenque Formation. The paleogeographic distribution of this new species spans at least 500 km along the southern Atlantic coast of South America. The living representatives of the Chaperiidae in the Southwest Atlantic do not seem related to A. spinettai. Fil: López Gappa, Juan José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina Fil: Pérez, Leandro Martín. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina

A Sr-isotope chronostratigraphy is presented for Miocene sediments deposited by the “Paranense” Sea along 1200 km of the southwestern Atlantic coast of Argentina and Uruguay. Numerical ages were obtained for shells of Aequipecten paranensis from the Argentinean Puerto Madryn Formation, Facies Balneario La Lobería, “Entrerriense Beds” of the Salado Basin, and Paraná Formation, and from the Camacho Formation (Uruguay). The 87Sr/86Sr ages fall into five age-groups that encompass the “Paranense” flooding in the latest Serravalian-Messinian interval. For the Puerto Madryn Formation, the ages span the latest Serravalian to the Tortonian and are stratigraphically coherent with the transgressive phase (11.9–10.4 Ma) and the regressive phase (10.2–9.82 Ma and 9.40–9.05 Ma) of that unit. Ages of 8.85–7.95 Ma for the “Entrerriense Beds” show them to be Tortonian while the Facies Balneario La Lobería, and the Paraná and Camacho formations span the age-range 7.50–6.00 Ma, comprising the Tortonian-Messinian interval. The regressive phase of the Puerto Madryn Formation, and the Facies Balneario La Lobería are respectively correlated with the basal and middle beds of the cliffs at Barranca Final, where the uppermost horizons of the Barranca Final Formation are exposed. The “Entrerriense Beds” are correlated with the “Cape Fairwheater Beds”. Dating the “Paranense” marine incursion permits a reappraisal of its paleogeography and differentiation of its deposits from those of the “Patagoniense” Sea. The flooding area was smaller than previously thought, with its northwestern-most boundary in the surroundings of the Santa Fe Province and its southernmost boundary in southern Santa Cruz Province. Moreover, the Paranaian Molluscan Bioprovince was coeval with the Valdesian Molluscan Bioprovince for 2.35 Ma and species included in the Aequipecten paranensis Zone lived for at least 5.90 Ma. Fil: del Río, Claudia Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina Fil: Martinez, Sergio. Universidad de la República; Uruguay Fil: Mc Arthur, John. University College London; Estados Unidos Fil: Thirwall M,. University College London; Estados Unidos Fil: Pérez, Leandro Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina

The Santa Cruz Formation (Early–Middle Miocene) is one of the most widespread sedimentary units of the Argentine Patagonia. This unit contains an abundant and taxonomically diverse fossil vertebrate fauna, especially in mammals. Thus, the paleoecological and paleoenvironmental information derives mainly from the analysis of the vertebrate assemblages, as well as from the ichnological and paleobotanical evidence. The record of freshwater bivalves assigned to the species Diplodon cf. colhuapiensis Ihering, 1903 from the Santa Cruz Formation, collected in the locality of Barrancas Blancas (Estancia Santa Lucía), at Río Santa Cruz, allows us to infer the particular paleoenvironmental conditions setting during the deposition of the bearing levels. Considering this record, we propose that Diplodon, which was originally assigned to the “Sehuenense stage” (piso sehuenense of F. Ameghino), could have come from the Early–Middle Miocene of the Santa Cruz Formation. In this sense, the specimens referred to Diplodon cf. colhuapiensis suggest the existence of an established community of Hyriidae mollusks at the upper-middle levels of the Santa Cruz Formation. The presence of freshwater bivalves suggests that the depositional environment of this unit included the existence of water courses. The identification of the genus in the Santa Cruz Formation validates its presence in the Early Miocene and extends its southern distribution to the latitude of Río Santa Cruz (~ 50º S)., La Formación Santa Cruz (Mioceno Temprano–Medio), es una de las unidades sedimentarias más extendidas de la Patagonia argentina. Esta unidad contiene una gran abundancia y diversidad taxonómica de vertebrados fósiles, especialmente de mamíferos. De esta manera, la información paleoecológica y paleoambiental proviene principalmente del análisis de la asociación de vertebrados, como también la evidencia icnológica y paleobotánica. El registro de bivalvos de agua dulce asignados a la especie Diplodon cf. colhuapiensis Ihering, 1903 de la Formación Santa Cruz, recolectado en la localidad Barrancas Blancas (Estancia Santa Lucía), cerca del Río Santa Cruz, permite inferir las condiciones paleoambientales de la depositación de sedimentos de los niveles portadores de los especímenes. Teniendo en cuenta estos restos, proponemos que el material de Diplodon originalmente asignado al “piso Sehuenense” (piso sehuenense de F. Ameghino), podrían provenir del Mioceno Temprano–Medio de la Formación Santa Cruz. En este sentido, el registro de Diplodon cf. colhuapiensis confirma la existencia de una población establecida de moluscos de la familia Hyriidae en los niveles medio-altos de la Formación Santa Cruz. La presencia de bivalvos de agua dulce, probablemente habitando canales fluviales, sugiere la existencia de cursos de agua bien desarrollados en el ambiente depositacional de la unidad. La identificación del género en la Formación Santa Cruz valida su presencia en el Mioceno Temprano y extiende su distribución sur a la latitud actual del Río Santa Cruz (~ 50º S)., Facultad de Ciencias Naturales y Museo

Fil: Perez, Leandro Martin. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Division Paleozoologia Invertebrados; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - La Plata; Argentina

Selenariidae Busk 1854 (Bryozoa) is considered endemic to Australia and New Zealand. Here we describe a new species of Selenaria Busk 1854 from the lower Miocene Monte León Formation (Patagonia, Argentina). Selenaria lyrulata sp. nov. is characterized by autozooids with a lyrula-like, anvil-shaped cryptocystal denticle, opesiular indentations and lateral condyles, as well as avicularia with a shield of fused costae. This is the first record of a selenariid bryozoan in South America., Facultad de Ciencias Naturales y Museo

The top of the Querales Formation is well exposed at the Quebrada Corralito section, 17 m thick, in northern Venezuela. The section, dominated by siliciclastic accumulations of fine-grained sediments, preserves one cycle of transgressive–regressive phases of the deltaic environments facing the marine platform. An X-ray analysis revealed kaolinite as the main clay mineral. The age ranges from late Early Miocene to early Middle Miocene—zones N8 to N9, Late Burdigalian to Langhian. The section shows low biodiversity, including eleven macroinvertebrate taxa and two ichnotaxa; at its base, it contains mostly plant debris and amber from the continent, thus revealing a continental source near the littoral zone. Its middle portion preserves macroinvertebrates from the littoral zone, but also including the cephalopod Aturia sp., transported by a hydraulic flow to an area of greater depth; these macroinvertebrates are absent from overlying sections, at a time in which the basin was flooded most. The X-ray diffraction on six rock samples revealed mainly the presence of quartz with calcite, subordinated plagioclase and traces of potassium feldspar. Other minerals that compose this stratigraphic section are pyrite, dolomite and siderite, but they are disseminated in a siltstone. The section is dominated by mudstone sediments. The succession is kaolinite in the most pure fraction, and in lesser proportion smectite and illite; the stratified illite–smectite, chlorite and chlorite–smectite are present in low quantity. The mineralogical components of a molluscan valve were also examined, showing abundant pyrite, and moderate amounts of siderite and dolomite. In a part of the section, we recorded a rich assemblage of calcareous microfossils with foraminifers, nannofossils and marine ostracods. In the foraminiferal assemblage, 99 % correspond to planktonic forms. Most macroinvertebrates from benthonic assemblages suggest that they may have inhabited a near-shore marine environment, and sporadically experienced storm transport to deeper, shelf waters. Fil: Pérez, Leandro Martín. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Perez Panera, Juan Pablo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina. YPF - Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Aguilera, Orangel A.. Universidade Federal Fluminense; Brasil Fil: Ronchi, Diana I.. YPF - Tecnología; Argentina Fil: Sánchez, Rodolfo. Municipio de Urumaco. Museo de Paleontología; Venezuela Fil: Manceñido, Miguel Oscar. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Sánchez Villagra, Marcelo R.. Universitat Zurich; Suiza

A fractured femur of a giant fossil penguin from the Anthropornis nordenskjoeldi Biozone (Late Eocene), Isla Marambio (Seymour Island), Antarctica (La Meseta Formation) is described. Palaeoecological, palaeopathological and taphonomical implications derived from the analysis of the kinds of fractures identified are also discussed. The main fracture has irregular margins, indicating there was collagen in the bone at the time of the impact. In this fracture, a mineral deposit was also identified as a fracture hematoma. According to the antemortem classification of fractures, it was produced by an indirect mechanism, provocating a “butterfly wing” or “third fragment” fracture. The remaining fractures are assigned to times of biostratinomic and fossil diagenesis.

The fossil record of rebbachisaurid sauropods has greatly increased recently (Calvo and Salgado, 1995; Bonaparte, 1996; Dalla Vecchia, 1998; Sereno et al., 1999, 2007; Medeiros and Schultz, 2001; Pereda-Suberbiola et al., 2001, 2003; Salgado et al., 2004, 2006; Gallina and Apestegu´ıa, 2005; Apestegu´ıa, 2007; Mannion, 2009). The first fossil remains belonging to this group were described by Nopcsa (1902) but only recently recognized as a rebbachisaurid (Calvo and Salgado, 1995; Apestegu´ıa, 2007). Lavocat (1954) erected Rebbachisaurus garasbae, which has a scapula with broad, ‘racquet’-shaped blade, and a mid-dorsal vertebra with a very tall neural spine. This family is mostly known from rather fragmentary remains, and many specimens are unpublished or only partially described (Gallina and Apestegu´ıa, 2005)... Fil: Haluza, Alejandro. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; Argentina Fil: Canale, Juan Ignacio. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Otero, Alejandro. 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; Argentina Fil: Pérez, Leandro Martín. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina Fil: Scanferla, Carlos Agustín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentina

La Formación Paraná (Mioceno tardío) aflora de forma discontinua en la Provincia de Entre Ríos, Argentina, a lo largo del río Paraná entre las ciudades de La Paz y Victoria. Estos sedimentos fueron depositados en el marco del ascenso global del nivel del mar que inundó la cuenca chacoparanense. El arreglo regresivo de los estratos en el perfil litoestratigráfico indica el movimiento del agua retirándose de la cuenca, acumulando los sedimentos de los depósitos marinos propios de esta unidad litoestratigráfica. Producto de este avance del mar y apoyados por la afinidad entre la fauna del mar Caribe con las del Atlántico sur, algunos autores propusieron la existencia de una conexión a través de un brazo marino entre las grandes cuencas amazónica y chacoparanense. Con el objetivo de determinar la plausibilidad de esta hipótesis, así como la exacta composición de la fauna, sus relaciones paleobiogeográficas y el contexto geológico y paleoambiental en que se depositaron los sedimentos de la Formación Paraná, se estudiaron 13 localidades ubicadas en la provincia de Entre Ríos, se levantaron perfiles litológicos en 12 de ellas, se analizaron las secciones sedimentológicamente (mediante descripciones megascópicas y petrográficas), se dató un estrato de forma indirecta una de las localidades resultando una edad isotópica por 87Sr/86Sr de 9,47 Ma y se realizó un muestreo paleontológico controlado. Se analizaron los aspectos tafonómicos (tanto atributos bioestratinómicos como diagenéticos) y paleoecológicos (reconociendo y analizando estadísticamente categorías ecológicas). Se recolectaron un total de 1890 especímenes y se estudiaron 10 colecciones en repositorios del país y del exterior. El análisis sistemático de las asociaciones permitió reconocer una biodiversidad corregida de 67 taxones de invertebrados e icnofósiles, incluyendo nuevas formas. Se ajustó el modelo para la interpretación del ambiente depositacional de la unidad, propuesto aquí como un gran mar interior de condiciones someras, de baja profundidad y dominado por mareas, discutiéndose la inclusión del llamado “Conglomerado Osífero” dentro la Formación Paraná. Se elaboró un esquema paleoecológico que integra la evidencia obtenida del análisis del registro fósil, permitiendo proponer la fauna como una asociación mixta que incluyó formas marinas de ambientes litorales y otras de áreas de menor salinidad que habitaron en subambientes de la misma formación. Se corroboraron las relaciones paleobiogeográficas de la fauna de la Formación Paraná, en relación con otras unidades de edades equivalentes de América del Sur, siendo la Formación Camacho la que tiene mayor afinidad taxonómica. Finalmente, de los resultados obtenidos, se apoya la hipótesis de una conexión intermitente entre las cuencas Chacoparanense y Amazónica que permitió el pasaje de taxones de ambientes acuáticos de agua dulce o de baja salinidad entre ambas cuencas, y se descarta la idea de una conexión netamente marina epicontinental entre ambas cuencas., The Paraná Formation (late Miocene) outcrops continuously along the left bank of the Paraná River, in the province of Entre Ríos, Argentina, between the cities of La Paz and Victoria. These sediments were deposited during a global sea level rise that flooded the Chaco plains. The regressive beds in the lithostratigraphic section indicate a retreating sea that accumulated the marine sediments constituting the Paraná Formation. Some authors suggested –on the basis of its faunal affinities with the Caribbean faunas– the existence of some kind of connection by means of a marine seaway linking northern and southern South America. In order to determine the plausibility of this hypothesis, together with the exact composition of the fauna, its paleobiogeographic relations and the geological and paleoenvironmental contexts in which the unit was deposited, 13 localities in the province of Entre Ríos were studied, and sections were measured at 12 of them. Sections were sedimentologically analyzed (by megascopic and petrographic descriptions). One bed at one of the localities was indirectly dated, yielding an 87Sr/86Sr age of 9.47 Ma. A controlled paleontological sampling was performed. Taphonomic aspects were analyzed (biostratinomically and diagenetically). Paleoecological aspects were also dealt with (recognizing and statistically analyzing ecological categories). A total of 1890 specimens were collected, and 10 previous collections were consulted. Systematic analysis of the associations allowed recognizing a corrected biodiversity of 67 invertebrate taxa and ichnotaxa, including new species. Environmental interpretation was adjusted and is herein considered as a great interior tide-dominated shallow sea. Inclusion of the “Conglomerado Osífero” in the Paraná Formation is discussed. A paleoecological framework integrating information from the fossil record is set forth, suggesting a mixed fauna including littoral and others from low salinity subenvironments. The paleobiogeographic relation of the Paraná Formation with other equivalent units was corroborated, resulting in a higher affinity with the Camacho Formation from Uruguay. Results obtained support the hypothesis of an intermittent connection between the Chaco-Paranense and Amazonian basins, allowing the dispersion of freshwater or low-salinity taxa from one area to the other. A marine epicontinental connection between these two basins is discarded., Facultad de Ciencias Naturales y Museo

«La Bonita» is a fossiliferous locality close to the town of Cerro Policía, Río Negro Province, Argentina. At the quarry are exposed siliceous rocks belonging to the Bajo de la Carpa and Anacleto formations (Santonian-Campanian), separated by an unconformity from the Rentería Formation (Upper Pliocene-Pleistocene). The Bajo de la Carpa Formation is composed of sandstones, fine beds of conglomerates, alternate with pelites and wackes beds. The Anacleto Formation is composed of sandy to pelitic beds. The Rentería Formation is dominated by conglomerates with clasts that reach 15 cm in length, included in a sabullitic matrix. The facies analysis suggests a fluvial regime, with a subacuatic control with changes from mid to low energy. The lenticular-shaped sandy channels with crossed stratification point to an unidirectional flow in the transporting agent and bioclasts. The taphonomical analysis suggested that the dinosaur dies close to the river margins, being rapidly incorporated to the fluvial sediments that sepulted the specimen in successive events. The spatial distribution and bone relations suggest a very short transport from the source area, with a slight northward movement. The presence of two caudal vertebrae series with an opisthotonous articulation pattern, suggests that the animal was exposed long enough to permitt the rigor mortis and dissecation. The disarticulation degree also point to some amount of weathering of the skeleton before being sepulted. However, the exceptional periostium preservation in many cases suggests a very short subaerial exposure. La localidad fosilífera «La Bonita» se ubica en las cercanías del pueblo de Cerro Policía, provincia de Río negro, Argentina. Allí afloran sedimentos continentales silicoclásticos pertenecientes a las Formaciones Bajo de la Carpa y Anacleto (Santoniano-Campaniano) separadas en discordancia de la Formación Rentería (Plioceno Superior-Pleistoceno). La Formación Bajo de la Carpa se compone de areniscas, finos bancos conglomerádicos alternados con pelitas y capas de vaques. La Formación Anacleto está compuesta de capas arenopelíticas. La Formación Rentería está mayormente compuesta por conglomerados con clastos que alcanzan 15 cm de longitud, incluidos en una matriz sabulítica. El análisis de facies sugiere un regimen fluvial, con un control subacuático que oscila entre energía media y alta. Los canales arenosos, lenticulares, poseen estratificación entrecruzada indicando un agente de transporte unidireccional. El análisis tafonómico indicaría que el dinosaurio murió en las cercanías de los márgenes del río, siendo rápidamente incorporado a los sedimentos fluviales y sepultado en sucesivos eventos. La distribución especial de los huesos revela un corto transporte desde la fuente de aporte, con una leve orientación hacia el norte. La presencia de dos series de vertebras caudales con arqueamiento opistótono indican que el animal fue expuesto un período suficiente de tiempo para que actúe el rigor mortisy la disecasión. El grado de desarticulación sugiere, también, cierta exposición subaérea, aunque no en gran medida, debido a la exquisita preservación del hueso periostial. Facultad de Ciencias Naturales y Museo

International audience; Traditionally, the use of good techniques to improve software modularity, such as advanced separation of concerns, has no impact in the user experience, for example while navigating Web software. While the intent of these techniques is to simplify evolution and maintenance, navigation design quality is often seen as an unrelated concern. In this paper we present a novel approach for improving navigation in Web applications by using some of the core application's concerns (called navigational concerns) to derive their navigational structure. Using some realistic examples we show that, by carefully using these concerns, we can improve the user experience. Some implementation issues are discussed and a thorough comparison with related ideas in the Web Engineering field is presented.