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Bryozoans with calcified frontal shields formed by the fusion of costae, collectively constituting a spinocyst, are traditionally assigned to the family Cribrilinidae. Today, this family is regarded as nonmonophyletic. In the Argentine Cenozoic, cribrilinids were until recently represented by only two fossil species from the Paleocene of Patagonia. This study describes the first fossil representatives ofJolietinaandParafigularia:J. victorian. sp. andP. pigafettain. sp., respectively. A fossil species ofFigularia,F. elcanoin. sp., is also described. The material comes from the early Miocene of the Monte León and Chenque formations (Patagonia, Argentina). For comparison, we also provide redescriptions of the remaining extant species ofJolietina:J. latimarginata(Busk, 1884) andJ. pulchraCanu and Bassler, 1928a. The systematic position of some species previously assigned toFigulariais here discussed.Costafigularian. gen. is erected, withFigularia pulcherrimaTilbrook, Hayward, and Gordon, 2001 as type species. Two species previously assigned toFigulariaare here transferred toCostafigularia, resulting inC. jucundan. comb. andC. tahitiensisn. comb. One species ofFigulariais reassigned toVitrimurella, resulting inV. amplan. comb. The family Vitrimurellidae is here reassigned to the superfamily Cribrilinoidea. The subgenusJuxtacribrilinais elevated to genus rank.Inferusiais regarded as a subjective synonym ofParafigularia.Parafigularia darwiniMoyano, 2011 is synonymized withI. tayloriKuklinski and Barnes, 2009, resulting inParafigularia taylorin. comb. Morphological data suggest that these genera comprise different lineages, and a discussion on the disparities among cribrilinid (sensu lato) spinocysts is provided.UUID:http://zoobank.org/215957d3-064b-47e2-9090-d0309f6c9cd8

The cheilostome bryozoan genus Taylorius Gordon, 2014 comprises six named living and fossil species from New Zealand and one Recent species from South Africa. Taylorus nom. nov. is proposed as a re...

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.

Dermal ossifications (osteoderms, dermal ossicles, osteoscutes) appear independently in various tetrapod lineages. In mammals, however, dermal ossifications are only present in some members of Xenarthra. This clade includes Cingulata (armadillos and their relatives), and Pilosa, including Vermilingua (anteaters) and Folivora (sloths). In extant xenarthrans, osteoderms are invariably present in cingulates whereas they are absent in pilosans. Among extinct sloths, however, a limited number of taxa possessed dermal ossifications. Records of mummified skins of ground sloths bearing osteoderms found in Cueva del Milodon (Southern Chile), with a late Pleistocene age, allowed us to analyze their micro- and macroscopic morphology. The main goal of this study is to closely examine a portion of a mylodontid skin portion using radiography. The arrangement, morphology and internal structure of the ossicles are analyzed and the results are discussed in the context of previous research. The results we obtained indicate that ossicles vary in shape and size, and the integument has four different patterns of arrangement of the ossicles: that is, areas without ossicles, disorganized ossicles, rows, and mosaic areas. The latter has two variants, with clusters of ossicles forming rosettes or stars. Thin sections of the ossicles allowed us to recognize and describe anatomical features of the bone and its mode of growth. Finally, paleobiological and functional considerations of the dermal armor are discussed along with its phylogenetic and chronological implications.

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

This paper describes an integrated field, petrographic and geochemical study of the Puesto del Museo Formation, a poorly known unit that evidences a Cenozoic transgression at the southernmost Golfo San Jorge Basin. The most striking features of the Puesto del Museo Formation is its occurrence as restricted ~20 m-thick-outcrops composed exclusively of friable cross-stratified grainstones. We analyzed the sedimentary facies and facies associations in order to reconstruct the depositional setting. The petrographic characterization allows assessing the composition as a very homogeneous lithological succession dominated by skeletal grainstones. Geochemistry of trace elements (Mn, Sr, Rb, rare earth elements plus yttrium = REY), and stable isotopes (C and O) were used to characterize the grainstones compositionally, and to constrain environmental and climate conditions that controlled its deposition. The diagenetic environmental comprehension helped to the interpretations of the syn- and post-depositional conditions related to the grainstones. Finally, the stratigraphic position of the Puesto del Museo grainstones into the context of the basin is discussed. This succession can be correlated with the Patagonian marine event (i.e., Golfo San Jorge and Austral basins) that took place during the late Oligocene–early Miocene, related to an elevated global sea level controlled by glacio-eustatic conditions. Fil: Gómez Peral, Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina Fil: Raigemborn, María Sol. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina Fil: Richiano, Sebastián Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; Argentina Fil: Arrouy, Maria Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina Fil: Odino Barreto, Andrea Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; 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 Fil: Sial, Alcides N.. Universidade Federal de Pernambuco; Brasil Fil: Ferreyra, Camila. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; 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 bryozoan genus Aspidostoma Hincks, 1881 has been regarded as the only representative of the Aspidostomatidae Jullien, 1888 in Argentina to date. Its type species, Aspidostoma giganteum (Busk, 1854), is presently distributed in the Magellanic Region (Argentina and Chile) and has been recorded in Oligocene and Miocene fossil deposits of Santa Cruz and Chubut, respectively. New material from San Julián (late Oligocene), Monte León (early Miocene), Chenque (early to middle Miocene), and Puerto Madryn (late Miocene) formations suggests, however, that A. giganteum is not represented in the fossil record. Material from Puerto Madryn Formation previously regarded as A. giganteum is here recognized as Aspidostoma roveretoi new species. Aspidostoma ortmanni Canu, 1904 is revalidated for the species from the San Julián Formation. Aspidostoma armatum new species and Aspidostoma tehuelche new species are introduced for material from the Monte León and Chenque formations, respectively. Aspidostoma incrustans Canu, 1908, from the early Miocene, is redescribed. Melychocella Gordon and Taylor, 1999, which differs from Aspidostoma in having vicarious avicularia and lacking a median ridge and a quadrangular process proximal to the opesia-orifice, is so far represented by three Paleogene species from the Chatham Islands (Southwest Pacific). The material from Monte León allowed us to transfer Aspidostoma flammulum Canu, 1908 to Melychocella, resulting in the new combination Melychocella flammula (Canu, 1908). Melychocella biperforata new species is described from the lower Miocene Monte León and Chenque formations. The presence of Melychocella in the Neogene of Patagonia extends its geographic distribution and its temporal range.UUID: http://zoobank.org/d84df2d8-cab2-4e74-82b8-7c67d938a58f

THE Argentinean fossil record of vertebrate footprints is significant and has been extensively studied; however, sites with bird tracks are scarce and less known (Bonaparte, 1965; Aramayo, 1991, 2007; Galli et al., 1992; Aramayo and Manera de Bianco, 1987, 1990, 1996; de Valais and Melchor, 2008; Genise et al., 2009; Melchor, 2009; Alonso, 2012; Aramayo et al., 2015). Although there are some studies of fossil footprints referred to Aves, there are no detailed descriptions or taxonomical assignations of such traces. A bird trackway with three footprints was found in the lower levels of the Guandacay Formation (upper MiocenePliocene) (Ayaviri, 1967), Grupo Chaco (Stebinger, 1920; White, 1925), at the “Río Iruya” section, 62 Km NW of the city of San Ramón de la Nueva Orán (Salta Province, Argentina; Fig. 1.1). This unit is part of the fill of the Neogene foreland basin of Sierras Subandinas Australes. This Subandean terrain is a thin-skinned fold-thrust belt system which represents the easternmost expression of the deformation of the central Andes. Compressive tectonics created a foreland basin with clastic sequences of continental rocks of approximately 7500 m of thickness (Hernández et al., 1996; Ramos, 1999). The aim of this contribution is to report a new record of Aramayoichnus rheae Aramayo et al., 2015, from the Neogene of Northwestern Argentina, based on tridactyl footprints attributed to bird activity. This fossil evidence expands the paleogeographical and temporal distribution of this ichnospecies, showing the presence of rheids in the Late Miocene of the Subandean region. The footprints were preserved as natural casts (convex hyporeliefs) in brownish-grey, fine to medium grain conglomerates; the base of the level is in contact with reddishreddish brown mudstones and very fine sandstones (Fig. 1.2). The hypothesis that a rheiform bird could have registered this trackway is herein considered in association with the fossil record of the group in a stratigraphic and biogeographic context. Fil: Tineo, David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina Fil: Pérez, Leandro Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina Fil: Bona, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina Fil: Comerio, Marcos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina Fil: Noriega, Jorge Ignacio. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina Fil: Poire, Daniel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; 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

Platychelyna secunda sp. nov. is described based on material collected in the Monte León Formation, Patagonia, Argentina (early Miocene). This is the second species of Platychelyna Hayward and Thorpe to be described and the first fossil representative, expanding the stratigraphic range of the genus by ~20 Ma. P. secunda and P. planulata Hayward show similar geographic distributions in the southern tip of South America. Zooid size is ~50% larger in the recent species compared to the fossil one, which could be related to the cooling of the water masses in the Southwest Atlantic since the opening of the Drake Passage towards the end of the Oligocene. 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. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: Griffin, Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina

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

El objetivo de este trabajo es el análisis tafonómico del holotipo de Crossvallia unienwillia Tambussi, Reguero, Marenssi and Santillana, 2005, con el fin de incrementar el conocimiento acerca del registro fósil de vertebrados de la Formación Cross Valley, aflorante en el área central de la Isla Marambio (Seymour), Península Antártica. El análisis del estado preservacional de los restos de Crossvallia unienwillia ofrece importantes datos para las reconstrucciones paleoambientales y áreas depositacionales, claves para la comprensión de la historia evolutiva temprana de los pingüinos. Diferentes técnicas, incluyendo el estudio de secciones petrográficas, observaciones en MEB, detector de electrones secundarios, detector de electrones dispersos, difracción de rayos X y rayos X de energía dispersiva, fueron aplicados para distinguir las alteraciones bioestratinómicas de aquellas fósil-diagenéticas. Los restos de Crossvallia forman parte de una asociación típicamente marina, incluyendo además tiburones y macroinvertebrados. Los sedimentos portadores indican un ambiente de baja energía, ya sea por debajo del tren de olas, o bien protegido de la acción de las olas. En cualquiera de estos casos, las condiciones marinas iniciales cambiaron hacia otras con un flujo regular de material continental sedimentario. Crossvallia unienwillia fue una hembra buceadora, que atravesó varios periodos de muda antes de su muerte. Procesos bioestratinómicos consistentes con un bajo transporte y un rápido sepultamiento que habría prevenido la acción de procesos destructivos tales como la meteorización son inferidos para este caso. El enterramiento rápido favoreció la preservación de los elementos bajo condiciones anóxicas. La corrosión superficial, las fracturas y el relleno de cavidades internas, sugiere que los procesos destructivos fueron solo importantes luego del sepultamiento durante estadios telodiagenéticos. La ausencia de otros vertebrados fósiles en el Alomiembro Cross Valley C es el resultado de esos procesos, mientras que de manera contraria, el ambiente depositacional pareció haber sido óptimo. The purpose of this paper is to provide a taphonomic analysis of the holotype of Crossvallia unienwillia Tambussi, Reguero, Marenssi and Santillana, 2005, in order to improve the knowledge of the vertebrate record of the Cross Valley Formation, a unit exposed in the central area of Marambio (Seymour) Island, Antarctic Peninsula. Analyses of the preservational state of the skeleton assigned to Crossvallia unienwillia offer important data for palaeoenvironmental and depositional reconstructions, key for the understanding of the early evolutionary history of penguins. Different techniques, including petrographic sections, SEM observation, Secondary Electrons Detectors, backscattered electrons detectors, microanalysis for probe of electrons, and X-ray diffraction were applied in order to distinguish biostratinomic from fossil diagenetic damage. Fossil bones of Crossvallia are associated with a typical marine assemblage including shark remains and macroinvertebrates. The hosting mudstones suggest a low-energy environment either below the wave-base or protected from wave action. In any case initial marine conditions changed to other with regular influx of land-derived sedimentary material. Crossvallia unienwillia was a female diver that passed through several molting periods before death. Biostratinomic processes consistent with little transport and rapid burial which would have prevented the action of destructive processes such as weathering and carnivores or scavenging, are inferred. The rapid burial favored the initial preservation of the elements under anoxic conditions. The surficial corrosion, fractures, and the internal filling of the cavities, suggest that destructive processes were only important after final burial during the telodiagenetic stage. The absence of more vertebrate fossil remains in the Cross Valley C Allomember is the result of those destructive processes, whereas on the contrary the original depositional environment appears to have been optimal. Fil: Acosta Hospitaleche, Carolina Ileana Alicia. 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 Paleontología Vertebrados; Argentina Fil: Pérez, Leandro Martín. 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 Paleozoología Invertebrados; Argentina Fil: Marenssi, Sergio Alfredo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; Argentina Fil: Reguero, Marcelo Alfredo. 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 Paleontología Vertebrados; Argentina

The bryozoan fauna from the South American Cenozoic is poorly known. The study of new material collected in the Monte León Formation (early Miocene), gave us the opportunity to describe four new species: Valdemunitella canui n. sp., Foveolaria praecursor n. sp., Neothoa reptans n. sp., and Calyptotheca santacruzana n. sp. Two of them (V. canui and C. santacruzana) were first recorded by F. Canu and interpreted as recent species from the Australian bryozoan fauna, but are herein described as new species. The stratigraphic range of Otionella parvula (Canu, 1904) is extended to the early Miocene. The present study emphasizes the close relationships between the South American Neogene bryozoan faunas and those of other Gondwanan sub-continents such as New Zealand and Australia. Fil: Pérez, Leandro Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina Fil: López Gappa, Juan José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales ; Argentina Fil: Griffin, Miguel. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

We examine three avian remains from the Ultima Esperanza cave complex. This site is a Natural Monument situated along the flanks of Cerro Benitez, Magallanes Region of Chile. A tarsometatarsus (MLP 94-VIII-10-12) is assigned to Rhea pennata, and a humerus (MLP 94-VIII-10-111) to Phalacrocorax brasilianus. Both, R. pennata and P. brasilianus, are currently distributed in the Magallanes Region, and their presence within the cave can be easily explained by the cut marks found on the tarsometatarsus, that evidence human consumption. The absence of traces on the humerus is not decisive in this regard, because the wings are not the most fleshy parts of the body and therefore, not the preferred piece by predators. It can represent the waste. A small bill (MLP 94-VIII-10-140) of a passerine bird belongs to a fresh bone and should be treated as contamination.

Hippoporidra is a cheilostome bryozoan that predominantly encrusts gastropod shells inhabited by hermit crabs. The genus has a Pan-Atlantic distribution and its fossil record ranges from the Eocene to Holocene. Cellepora patagonica Pallaroni is here transferred to Hippoporidra and its autozooids and avicularia are described for the first time based on scanning electron microscopy. Hippoporidra patagonica can be distinguished from the remaining species of the genus by the peculiar shape of its interzooidal avicularia and the morphology of its orifice, which is semicircular, with a straight proximal border. In addition, many specimens have adventitious avicularia located on a suboral umbo. The record of Hippoporidra patagonica (Pallaroni) in the Gran Bajo Member of the San Julian Formation (late Oligocene) in Patagonia confirms the presence of this genus at the southern tip of South America and indicates a Pan-Atlantic distribution during the Cenozoic.

Outcrops of the Yecua Formation (late Miocene) are exposed for approximately 230 m along the La Angostura section of the Piraí River (50 km southwest of Santa Cruz de la Sierra). These reveal massive (argillic palaeosols) and laminated (quiet-water lacustrine and marsh settings) mudstones interbedded with thin sandstones containing microfossils, molluscs and vertebrate remains. Significantly, the succession hosts a giant crocodylian, Mourasuchus (Alligatoridae, Caimaninae), which is represented by both skull and postcranial fragments found in association with freshwater turtles and fishes. Mourasuchus was distributed widely from the middle Miocene of Colombia to upper Miocene of Venezuela, Brazil and Argentina, suggesting connections between major fluvial systems and an active mechanism for dispersal of South American freshwater vertebrates during the Miocene. 沿Pirai 河的La Angostura剖面Yecua组（晚中新世）的露头出露大约230米（Santa Cruz de la Sierra西南50公里）。这些露头显现出大量的（泥质古土壤）和层压的（静水湖泊和沼泽环境）泥岩，与薄砂层互层，后者含微化石、软体动物和脊椎动物的遗迹。重要的是，这些地层含有一个大型鳄鱼Mourasuchus（短吻鳄科，Caimaninae），其代表物是与淡水龟和淡水鱼共存的头骨和颅后碎片。 Mourasuchus广泛分布于哥伦比亚的中新世中期到委内瑞拉、巴西和阿根廷的上新世，说明中新世时主要河流系统的连通，及南美淡水脊椎动物的扩散机制。 Fil: Tineo, David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina Fil: Bona, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina Fil: Pérez, Leandro Martín. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleozoología Invertebrados; Argentina Fil: Vergani, Gustavo Dardo. Pluspetrol S.A. Buenos Aires; Argentina Fil: González Rigas, Gloria. Pluspetrol S.A. Buenos Aires; Argentina Fil: Poire, Daniel Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; Argentina Fil: Brandoni, Zulma Nelida. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina Fil: Legarreta, Pablo. Pluspetrol S.A. Buenos Aires; 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

During an ongoing revision of the Paraná Formation fauna of Argentina, the taxonomic status of Mactra bonariensis Philippi, 1893, was reassessed. The morphological characters of M. bonariensis provided in the original description and illustration do not allow clear delimitation of the species. The absence of type material of this species, coupled with difficulties in resampling the type locality due to urbanization, necessitates designation of a neotype. No records of this taxon were found in palaeontological and malacological collections. However, material collected from the Paraná Formation at 'La Juanita' (Entre Ríos, Argentina) comes from beds equivalent to those exposed at the locality from which Philippi described the original material. As this species may be confused with Quaternary and extant species from the region, a redescription is provided and a neotype designated. 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: Signorelli, Javier Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; Argentina

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

Different traces occur on fossil bones and teeth coming from the Early Miocene Gaiman Formation (Patagonia, Argentina). Most traces were attributed to the action of terrestrial and marine predators and scavengers. However, other traces on bones and teeth from this unit and one tooth from the Eocene La Meseta Formation (Antarctica) are attributed to chemical corrosion by lichens in recent times, that is, in a very late diagenetic time. The living lichens and calcium oxalate deposits occurring on the traces and their particular pattern indicates that they were not produced by vegetal roots. The lichens include reproductive structures which allowed a proper determination. A kind of corrosion pattern (Type 1) on bones and teeth from Patagonia is associated to Sarcogyne orbicularis K̈orber, Verrucaria sp. Schrad, and Buellia aff. punctiformis (Hoff.) Massal. The lichen Aspicilia aff. Aquatica produced rounded holes on an Antarctic tooth (Type 2). On the same tooth, the epilithic lichen Caloplaca sp. Th. Fries did not leave any kind of mark on the enameloid. Fil: Acosta Hospitaleche, Carolina Ileana Alicia. 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. Departamento Científico de Paleontología de Vertebrados; Argentina Fil: Marquez, Gonzalo Javier. 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. Cátedra de Palinología; Argentina Fil: Pérez, Leandro Martín. 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 Paleozoología Invertebrados; Argentina Fil: Rosato, Vilma Gabriela. 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. Instituto de Botánica Spegazzini; Argentina Fil: Cione, Alberto Luis. 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. Departamento Científico de Paleontología de Vertebrados; Argentina

Several traces of biological interaction were found on penguin bones from the basal levels (Aquitanian) of the Miocene Gaiman Formation in the lower Chubut valley of the Provincia del Chubut, Argentina. The fossil-bearing beds were deposited in littoral to sublittoral environments within sediments of mostly pyroclastic origin. We interpret many traces to have been produced by predators and/or scavengers while the penguins were still in a breeding area. Many bones show cracking marks due to aerial exposure. The material is disarticulated as is usual in recent breeding areas. Potential predators were coeval terrestrial mammals, most probably marsupial carnivores. After a marine transgression, these bones were buried or exposed on the sea bottom where they could be colonized by algae, sponges, cnidarians, and other benthic organisms. We identified sponge borings in several bones. Other traces are interpreted to have been produced by echinoderms feeding on sponges or algae. No evidence of other invertebrate p...

In this paper, a new species of fossil wood, Paraperseoxylon septatum sp. nov. (Lauraceae), from the Cretaceous of Puerto Yeruá Formation, is described. The fossil wood herein studied has features of the Lauraceae family, and particularly resembles the extant genus.Persea Mill. The possible climatic conditions of the Puerto Yerúa Formation were inferred using the Vulnerability Index, Mesomorphy ratios and the Taxon Independent Approach of the anatomical features present in the fossil wood described, suggesting a warm and humid to seasonally dry context. This material is the first record known from the Cretaceous of Northeastern Argentina and the earliest occurrence in the Southern Hemisphere of a fossil taxon with feature closest to Persea, and clearly establishes the presence of Lauraceae in Northeastern Argentina during the Cretaceous. Nowadays the genus Persea has a tropical and subtropical disjunct distribution in the Americas, Asia, and the Canary Islands. The present study provides information pertinent to understanding its phylogenetic context and biogeographic history. Fil: Franco, María Jimena. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina Fil: Brea, Mariana. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; Argentina Fil: Passeggi, Esteban. Provincia de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Universidad Autónoma de Entre Ríos. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones Científicas y Transferencia de Tecnología a la Producción; 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

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

The analysis of the hyoid apparatus of fossil xenarthrans provides insight on the form of the tongue and its function in food intake and intraoral processing. The hyoid ap- paratus of xenarthrans is notable for fusion among its ele- ments. The presence of a V-bone, a complex consisting of fused basihyal and thyrohyal bones, is a consistent and probably synapomorphic feature of xenarthrans. Fusion of other ele- ments is variable in fossil xenarthrans. Most fossil sloths retain independent elements, as in living dasypodids and mammals generally. Among nothrotheriids, the elements are slender and their articular surfaces indicate considerable mo- bility, and the relatively long and horizontal orientation of the geniohyoid muscle suggests considerable tongue protru- sion. Among mylodontines, such as Paramylodon and Glossotherium, the elements indicate relatively mobile articu- lations, except between the stylo- and epihyals. The relatively posterior placement of the apparatus and the length and alignment of the geniohyoid muscle indicate considerable capacity for tongue protrusion. Scelidotherium, however, had rigidly articulated stylohyal and epihyal, and the apparatus lies farther anteriorly, which together with the elongated, steeply inclined mandibular symphysis, indicates a relatively shorter geniohyoid muscle and thus more limited capacity for tongue protrusion. A similar situation is indicated for Megatherium, casting doubt on the classical reconstruction of this sloth as having a long prehensile tongue. Among cingu- lates Prozaedyus resembles living dasypodids, indicating con- siderable tongue protrusion important in food acquisition and intake. More extensive fusion of hyoid elements occurs in the cingulates Glyptodon and Proeutatus, in which the stylohyal and epihyal at least, are fused into a single element termed the sigmohyal. The presence of this element supports recent proposals of a sister-group relationship between glyptodonts and eutatines. The rigidity of the apparatus suggests limited tongue protrusion, but the tongue, in glyptodonts at least, was a powerful structure important for intraoral manipulation of food. J. Morphol. 271:1119-1133, 2010. 2010 Wiley-Liss, Inc.

«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.