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Discinids are a group of inarticulate brachiopods with organophosphatic shells and a very poor fossil record. we report for the first time the presence of this family in the Cenozoic of Patagonia, represented by two new species: Discinisca porvenir sp. nov. and Discinisca messii sp. nov., both found in marine deposits of the Gaiman Formation (Lower Miocene) in Chubut province, Argentina. Specimens come from four localities: Bryn Gwyn, Cañadón del Puma, Isla Escondida, and Punta Loma. The first species, D. porvenir sp. nov., presents a shell with subcircular to subtrapezoidal outline in dorsal view and maximum width located slightly anterior, apex near to the last quarter of the total valve length, and external sculpture formed by narrow concentric bands with irregular edges. In contrast, the second species, D. messii sp. nov., shows a valve with subcircular to circular outline in dorsal view with apex placed near to posterior margin, and external sculpture formed by concentric bands with a rounded triangular profile in transverse section. The new species seem to be related to the living D. lamellosa and D. laevis, respectively, both with a western South American distribution. The Gaiman Formation includes phosphatic nodules and abundant cases of well-preserved phosphatic vertebrate remains. Due to this, and the biostratinomic conditions deduced for vertebrates, the preservation of the brachiopods could be favoured. [ABSTRACT FROM AUTHOR]

Aplodinotus grunniens represents one of the most common, widespread, and unique freshwater fishes in North America. Understanding the evolutionary history of this sciaenid is challenging though as published palaeontological records are lacking. Existing literature documenting skeletal remains and otoliths is summarised herein to better understand divergence and biogeography of the extant A. grunniens and extinct Aplodinotus species. Fossil evidence indicates that in addition to A. grunniens, three putative, extinct, marine species in North America and two in South America existed. The North American fossil Aplodinotus range from Oligocene to early Miocene, while the genus extends to the middle Miocene in South America. All described extinct fossil Aplodinotus have been recovered from shallow marine sediments with the oldest from the U.S.A. Gulf Coastal Plain. All sites with extant A. grunniens are from freshwater deposits ranging from middle to late Miocene to Holocene in age which very closely approximate the modern geographic distribution and include a variety of preserved skeletal elements and otoliths. The disappearance of the fossil marine Aplodinotus in the early Miocene in the Gulf is interpreted to represent the genus' transition to brackish and eventually freshwater habitats and development of the extant species by the late Miocene. [ABSTRACT FROM AUTHOR]

The subfamily Dasypodinae (including Astegotheriini, Stegotheriini and Dasypodini) constitutes the sister group of the remaining diversity of 'armadillos', with an ancient divergence estimated in ca. 40 Ma. (Eocene). Dasypodini represent the only living Dasypodinae, with their oldest records, previous to this contribution, ranging from the middle Miocene (ca. 12 Ma). Here, we describe a new genus and species of armadillo from the middle Miocene deposits of La Victoria Formation (ca. 13 Ma, La Venta, Colombia), which represents the oldest known Dasypodini. Remains include an articulated fragment of the dorsal carapace, and the first described cranium of a Miocene Dasypodini. Despite that most of the characters support its inclusion within Dasypodini, its dorsal carapace shows an unique combination of characters from the clades Dasypodini and Euphractinae, allowing to carry out inferences about the transitional morphological processes that took place between both groups. The cladistics analysis corroborates the basal position of this new taxon within Dasypodini, in concordance with its stratigraphic provenance, and reinforces the idea of a tropical origin of the Dasypodini. Finally, the evolutionary history and palaeobiogeography of Dasypodini and Glyptodontinae (large cingulates) show noticeable parallelism, despite the fact that both represent different lineages with evident different ecological characteristics. [ABSTRACT FROM AUTHOR]

The modern pitheciids (titis, sakis, and uakaris) of northern South America represent one of the earliest radiations of platyrrhines and demonstrate morphological adaptations and ecological strategies for seed eating. While seeds can provide reliable resources for relatively long periods of time, they are often well protected by thick husks and hard seed coverings. Seeds also tend to be rich in lipids, but they may also be high in indigestible fiber. Even though seed eaters are found in each major primate radiation, only the pitheciids demonstrate primary adaptations for eating seeds. In this partly historical, partly contemporary review, I examine the ecological and anatomical correlates of seed eating. It is dedicated to two well‐known field primatologists: ecologist and conservationist J. Márcio Ayres; and anatomist and ecologist Warren G. Kinzey. Using observations in Kinzey (1992, Am J Phys Anthropol, 88, pp. 499–514) as a framework, I provide context and analysis for the intervening three decades of pitheciid research to identify what we know about this understudied group of primates and propose directions for future work. Highlights: Márcio Ayres and Warren Kinzey were pioneers in the study of pitheciid ecology in the late 20th century.The Pitheciidae is one of the oldest radiations of platyrrhines, identifiable by specialized dentition (used to open well‐protected fruit) by the middle Miocene.The subfamily, Pitheciinae (sakis, bearded sakis, and uakaris), are seed‐eating specialists using enlarged canines to open mechanically resistant foods and flat, crenulated molars to crush young and mature seeds.The benefits of seed eating lay in the long‐term availability of resources and relatively high lipid content of seeds. Dietary fiber (neutral detergent fiber [NDF]) appears to be the most significant constraint on eating seeds by pitheciines. [ABSTRACT FROM AUTHOR]

Iron (Fe) is a productivity-limiting nutrient in the ocean. However, the sources of dissolved Fe (dFe) in the deep ocean and how they respond to tectonic and climate changes are still poorly understood. In the northern hemisphere, dust flux to the low-latitude western Pacific has increased dramatically since the late Miocene associated with intense aridification of the Asian inland. Meanwhile, the terrigenous material supply to the open ocean might have also changed as a result of the reorganization of the Pacific circulation due to the gradual closure of seaways in the low latitudes. Therefore, the western Pacific is a characteristic region for understanding the sources of dFe in the deep ocean and their responses to long term climate changes. Here, we present data on isotopic evolution of dFe and dissolved Pb since ∼8 Ma based on ferromanganese crust METG-03 (16.0°N, 152.0°E, 3850 m water depth) in the western Pacific deep water. Our results show that δ56Fe of the crust remains fairly stable since the late Miocene, i.e., about −0.32±0.08‰ (2SD). We infer that δ56Fe of dFe in the deep western Pacific is relatively invariant at ∼0.45 ±0.1‰ based on the Fe isotopic fractionation between hydrogenetic crust and the seawater dissolved component. The reconstructed isotope signature is similar to the measured δ56Fe value (0.37±0.15‰) of the intermediate to deep waters in the modern low-latitude western Pacific region close to the island arcs, but is significantly higher than that of the eastern Pacific deep waters near South America which is controlled by the reductive dissolution of continental shelf sediments and the hydrothermal inputs (δ56Fe<−0.1‰). The deep-water 206Pb/204Pb ratio recorded by METG-03 displays systematic increase at about 8–4 Ma, reflecting increased input from sediment dissolution of low-latitude island arcs associated with reorganization of the western Pacific deep circulation. Notably, Fe isotopes of terrigenous materials from different sources are similar, while their dissolved Fe isotopic signatures released to the ocean are mainly controlled by the mechanism of particle dissolution. The stability of δ56Fe and systematic changes in Pb isotopes over the last ∼8 Ma thus suggest that Asian dust dissolution and hydrothermal inputs are likely only minor sources of dFe in the low-latitude deep western Pacific, while the acquisition and transport of dFe from shelf sediments by organic ligand binding in the oxic environment is the major dFe source which keeps stable on tectonic time scales since the late Miocene. [ABSTRACT FROM AUTHOR]

The Miocene crocodyliform fauna of South America is one of the most diverse of the world, and the late Miocene Urumaco Formation of Venezuela has one of its most important assemblages. Mourasuchus (Caimaninae) is one of the most peculiar crocodyliforms of the South American Miocene due to its unusual morphology, which prompted peculiar feeding habits to be proposed for this taxon. In this paper we present a redescription of the holotype of the species Mourasuchus arendsi (CIAAP-1297) from the Urumaco Formation of Venezuela. The redescription offered a thorough reassessment of the skull, mandibles and postcranium that comprise the holotype of M. arendsi, providing a comprehensive morphological description of this specimen for the first time. The data provided by this description prompted a review of the taxonomic status of M. arendsi, which has enabled the possibility of M. arendsi being a junior synonym of M. atopus to be considered and thoroughly discussed in this paper. An eventual confirmation of the synonymy does not change the phylogeny of the Caimaninae clade. This contribution also offers assessments on the ontogenetic status of the holotype of M. arendsi and on the differences on the closure of the scapulocoracoid synchondroses between Mourasuchus specimens. [ABSTRACT FROM AUTHOR]

Caimaninae is a South American lineage of crocodylians widely distributed in Brazil and composed of six species within three genera. Currently, there is insufficient information regarding growth strategies, growth rates, and ecology extracted from the bone microstructure. Here we present the first osteohistological study of both Caiman yacare and an unidentified fossil Caiman. Long bones of one specimen of C. yacare and of one fossil Caiman found at Solimões Formation (Acre Basin), were used to prepare the histological slides. The microstructure of C. yacare shows fibrolamellar complex present in the femur and tibia, while the humerus and radius of both C. yacare and the fossil Caiman revealed a slow-growing bone matrix with gradual decrease and effective stops. According to the results found here, Caimaninae seem to have the capability to adjust their growth rates in response to seasonal changes. The extant Caiman is classified as juvenile, but for the fossilized specimen no ontogenetic stage can be determined. Caiman yacare shows the presence of intraskeletal variability regarding the record of bone growth. We conclude that Caimaninae likely have been experiencing cyclical changes in growth rates in direct correlation to changes in seasons and environmental conditions since the Miocene. [ABSTRACT FROM AUTHOR]

The analysis of stable isotopes in fossil mammals is useful for reconstructing paleoenvironmental and paleoecological conditions, but has been rarely applied to the Neogene of South America. In this study, we perform an integrative analysis (including U–Pb zircon dates and mammalian stable isotopes data) for the Late Miocene–Early Pliocene of central Argentina. We provide radioisotopic ages for some classic fossiliferous localities in this region, including an age of 9.7 ± 0.3 Ma for Arroyo Chasicó and 4.5 ± 0.2 Ma for Farola Monte Hermoso, and address the interval covering the Chasicoan (Late Miocene), Huayquerian (Late Miocene–Early Pliocene), and Montehermosan (Early Pliocene) stages/ages. In the Chasicoan Stage/Age, taxa with mixed C 3 –C 4 diets are recorded, suggesting the existence of favorable conditions for the C 4 photosynthetic pathway before its full expansion. However, taxa represented across most of the Huayquerian Stage/Age show a preference for C 3 –based diets, which changes in the latest Huayquerian–Montehermosan stages/ages when an increase in the percentage of C 4 plants in the diet of notoungulates, rodents, and xenarthrans is recorded, coinciding with the global expansion of C 4 plants. For the first time, the dietary behavior of two South American endemic sparassodont metatherians (Lycopsis and Thylacosmilus) has been evaluated from using stable isotope; analysis of these hypercarnivores show differences in δ 13C values, suggesting prey partitioning, partly due to the difference in body size. The fossiliferous sites studied, and the new isotopic and chronological information obtained, provide more detailed paleoecological and paleoenvironmental contexts for the Argentine Pampas during the last stages of the isolation of South America and the first pulses of the Great Biotic American Interchange. In addition, the new ages allow to better adjust the arrival of the first Holarctic immigrants in the region. • First zircon dates from Neogene classic sites in central Argentina are provided. • An increase of C 4 plants values is recorded in mammal diets from Early Pliocene. • The δ 13C values of Lycopsis and Thylacosmilus suggest prey partitioning. [ABSTRACT FROM AUTHOR]

The middle to late Miocene Friasian sensu stricto, Colloncuran and Mayoan South American Land Mammal Ages (SALMAs) were established based on the mammals recovered from the Río Frías, Collón Curá and Río Mayo formations, respectively (southern Argentina and Chile). Records of Interatheriinae (Notoungulata) from these sediments have been known since the first contributions of Ameghino and Roth, but most of this material has only been superficially revised or is almost unstudied. Based on these old collections and new interatheriine records from Cerro Zeballos (Chubut Province), we improve the diagnosis of Caenophilus tripartitus, describe new and peculiar characters for this taxon, consider Epipatriarchus bifidens as Protypotherium cf. colloncurensis, and propose Epipatriarchus as a junior synonym of Protypotherium. In turn, the holotype of Epipatriarchus innexus is here identified as the mesotheriid Trachytypotherium sp. Therefore, only two genera of Interatheriinae, Protypotherium and Caenophilus, are recognized in the Friasian sensu stricto and Mayoan. We identify Protypotherium cf. endiadys and a probable new species of Protypotherium for the Friasian sensu stricto, P. cf. colloncurensis and Caenophilus tripartitus for the Mayoan, and C. tripartitus, P. colloncurensis and P. cf. endiadys for Cerro Zeballos. An extended phylogenetic analysis is performed, including species from low latitudes and new data for P. colloncurensis and Caenophilus tripartitus, with the latter recovered as a sister taxon to Miocochilius federicoi. Both Protypotherium and Miocochilius are recovered as paraphyletic. The updated information we present provides a better knowledge of Interatheriinae for the middle to late Miocene of southern South America. [ABSTRACT FROM AUTHOR]

True limpets of the genus Nacella (Patellogastropoda: Nacellidae) include at least 11 nominal species distributed in different provinces of the Southern Ocean. Here, we present new molecular analyses and a comprehensive morphological revision of Nacella confirming the validity of all the currently recognized species, but with important amendments to the published distributions of several. We also show that specimens collected along two fjords in the Beagle Channel, southern South America, constitute a new taxon: Nacella yaghana sp. nov. The phylogenetic position of this new taxon in our molecular tree reveals that it represents an ancestral South American lineage of Nacella, markedly separated from the previously recognized and evolutionary recent Magellanic radiation. In addition, this new Nacella species was clearly distinguished from the rest of the species by morphological comparisons, including shell characteristics, radular-tooth shape and configuration, as well as by the coloration pattern of the mantle tentacles. This study provides new evidence about the evolutionary history of this important Southern Ocean, marine, near-shore benthic group and the role of the Antarctic Circumpolar Current in the biogeography of the genus. [ABSTRACT FROM AUTHOR]

The evolution of the tropical lowland forests in northern South America is poorly understood, yet new insights into past composition and changes through time can be obtained from the rich and diverse fossil pollen record. Here we present a revision of two diagnostic Malvaceae taxa from the Cenozoic record of northern South America and we relate their evolutionary history to recently updated geological models. In our study we review the pollen morphology and botanical affinity of Rhoipites guianensis and Malvacipolloides maristellae, and integrate these data into a phylogenetic framework. We also produce distribution maps for both fossil and extant taxa, infer the phylogeny and historical biogeography of the lineages to which they belong, and identify their ecological associates and environmental settings. The closest extant relatives of Rhoipites guianensis (Grewioideae) are Vasivaea and Trichospermum , which are taxa of South American origin. During the late Eocene to early Miocene Rhoipites guianensis was widely distributed in the lowland floodplain environments of northern South America. The closest living relatives of Malvacipolloides maristellae (Malvoideae) are members of Abutilinae (e.g., Abutilon , Bakeridesia, Callianthe and Herissantia), which have their origin in the northern hemisphere. This taxon makes its first appearance in the fossil record of northern South America during the early Miocene, and is typically found in fresh water floodplain and lacustrine environments. Our study suggests that both taxa migrated across the Central American Seaway in the early Miocene (around 18 Ma), and virtually disappeared from the fossil record in northern South America during the middle Miocene, coinciding with Andean uplift. However, their descendants expanded and -in the case of the Abutilinae—diversified in the Andes. We conclude that the biogeographic history of these Malvaceae is influenced by Andean uplift and the incipient bridging of the Americas. Thereafter, climate change and diversification of the Andean landscape enabled their descendants to move upslope and into the Andes. • Two important Neogene Malvaceae shed new light on the biogeographic history of South America. • In the early Miocene our taxa migrated between the Americas in both directions. • In the middle Miocene these Malvaceae strongly declined in the fossil record. • Descendant taxa moved upslope into the Andes where Abutilinae radiated. • Uplift, bridging of the Americas, and climate change all influenced plant evolution. [ABSTRACT FROM AUTHOR]

Hegetotheriidae is one of the most advanced clades within the endemic South American placental Order Notoungulata. The speciesHegetotheriopsis sulcatusKramarz & Paz, 2013 differs from all other known hegetotheriids in having a peculiar combination of cranial and dental features, some of them shared with Archaeohyracidae (sister group of Hegetotheriidae). A previous cladistic analysis supportedH. sulcatusas the earliest diverging hegetotheriid. Nevertheless, a more recent analysis, based on a different data matrix, concluded that this species is an advanced form within the family, with the little-knownProhegetotherium sculptumAmeghino, 1897 (late Oligocene) being the most basal taxon. Here we present a revision of the concept and the content ofP. sculptumbased on a re-examination of the type specimens. We find that this material exhibits several dental and cranial characters not recognized in all previous studies; we conclude that no specimen other than the types can be assigned toP. sculptum, and that all the synonymies previously proposed (i.e.P. shumwayiandP. crassus) are unfounded. A new cladistic analysis, combining characters from the two aforementioned analyses, confirms the position ofH. sulcatusas the earliest diverging hegetotheriid. The taxon was originally described based on remains from early Miocene deposits in central and northern Patagonia (Sarmiento, Chichinales and Cerro Bandera formations). Here we report new material from the late Oligocene of Cabeza Blanca (central Patagonia), and reassign other material previously attributed toProhegetotheriumfrom presumably equivalent levels at Quebrada Fiera (central West Argentina). These remains extend the occurrence ofH. sulcatusback to the late Oligocene, and fill an important gap of the early record of Hegetotheriidae. [ABSTRACT FROM PUBLISHER]

Gaimanophis is an extinct boid genus represented so far by a single species ( Gaimanophis tenuis ) known by isolated vertebrae from the early Miocene of Patagonia. In this paper, a new species of Gaimanophis is described from the India Muerta Formation (late Miocene) of Tucumán province (Argentina). Gaimanophis powelli sp. nov. distinguishes itself from G. tenuis mainly in its larger size, prezygapophyses less slanting, neural spine shorter dorsally than ventrally, and zygosphene straight bearing an anteriorly protruding tongue. This record indicates a wider temporal and geographical distribution of the genus from the early Miocene of Patagonia to the late Miocene of northwestern Argentina. The recognition of a new species of boid in South America increases the known diversity of this group. Although boids have inhabited in this territory since the Paleocene, fossils belonging to the group only show a glimpse of the real past diversity in the continent. [ABSTRACT FROM AUTHOR]

Aim We analysed in detail a past marine incursion event in north-western Amazonia and measured its effect on the forest composition. We also determined the sediment provenance in the fluvio-estuarine system and reconstructed the overall floral composition of the Amazon lowland forest during the Miocene climatic optimum. Location A 60-m-thick sedimentary succession situated along the Caquetá River in Colombian Amazonia (0.77° S; 71.97° W). Methods Palynological, geochemical and statistical analyses were performed on samples from organic-rich sediments. Results The lower section was formed by fluvial floodplain deposits of Andean provenance rich in pollen of Malvacipolloides maristellae (aff. Abutilon) and Rhoipites guianensis (aff. Vasivaea). The middle section was formed by fluvial channel and estuarine swamp deposits of central Venezuelan provenance dominated by pollen of Mauritiidites franciscoi (Mauritia). Towards the top, the swamp deposits represent an estuarine floodplain with aquatic biomarkers, marine palynomorphs and mangrove pollen. The succession ended with fluvial floodplain deposits of central to southern Venezuelan origin with R. guianensis as dominant pollen type. Palynological diversity was high throughout the section with Andean- and Venezuelan-derived sediments each with their characteristic taxa. Tropical rain forest taxa, such as Arecaceae, Fabaceae, Sapotaceae, Malpighiaceae and Bombacoideae, were common in these sediments, although taxa adapted to drier conditions also occurred. We provide a 'figshare' link to an image library of selected taxa, as well as the raw counts and processed data. Main conclusions The fluvio-estuarine system was of mixed origin with sediments and palynomorphs from the emerging Andes, but also from an area situated in the modern Orinoco Basin. Marine influence was linked to the Venezuelan source area and thus of indisputable Caribbean origin. Overall, a mixed forest with drought-resistant components existed in the drainage system during the Miocene climatic optimum. Our data provide a novel insight into the composition of the tropical lowland forest and the environments in north-western Amazonia prior to the main uplift of the central and northern Andes. [ABSTRACT FROM AUTHOR]

The present contribution aims is to analyze the fossil record of the genus Echinorhinus in South America, and particularly Argentina. We made a first-hand examination of the species Echinorhinus pozzi from the early Miocene of Patagonia, and recognize it as a valid taxon. The species was originally described in the XIX century, and since then no author described or illustrated the original material based on observations of the actual specimens. The genus Echinorhinus is reported for the first time in late Miocene Paraná beds, based on the occurrence of fossil dermal spines. The species Echinorhinus maremagnum occurring in the latest Cretaceous outcrops from Patagonia in Chile and Argentina is considered valid and clearly distinguishable from E. lapaoi , contradicting recent claims that argue their synonymy. • Here we review the fossil record of Echinorhinus sharks from South America. • These sharks have a long and complex taxonomic history. • Here we discuss in detail the traits that are traditionally used to distinguish fossil species from this region. • Seeking to clarify the taxonomic status of the fossil species of Echinorhinus present in the southern cone. [ABSTRACT FROM AUTHOR]

Here we describe an isolated distal end of tarsometatarsus coming from the late Miocene levels of the Loma de Las Tapias Formation (San Juan Province, Argentina). The specimen was identified as a Thinocoridae, and constitutes the oldest record for the clade. It also represents the only Tertiary finding for the family from South America and one of the scarce avian remains reported from central Argentina. This record provides new information on the palaeobiogeography of the clade. [ABSTRACT FROM AUTHOR]

Here we describe isolated avian remains coming from the Chichinales Formation, at the Paso Córdoba locality, Río Negro province, Patagonia, Argentina. Present report constitutes the first analysis of an Early Miocene bird association in South America outside the Santa Cruz and Chubut provinces, and one of the scarce reports of avian remains for the Colhuehuapian SALMA. The remains represent a new genus and species of phorusrhacid ( Patagorhacos terrificus gen. et sp. nov.), a new species of rheid ( Opisthodactylus horacioperezi sp. nov.), and an indeterminate charadriiform. Although different in composition, the presence and relative abundance of rheids and phorusrhacids is a pattern that is also present in other Early Miocene Patagonian assemblages, especially those from the Santacrucian SALMA. In spite of such similarities, the description of new taxa indicates that the Chichinales faunas were different to some degree from other Early Miocene bird assemblages. [ABSTRACT FROM AUTHOR]

The vast mammal diversity of the Neotropics is the result of a long evolutionary history. During most of the Cenozoic, South America was an island continent with an endemic mammalian fauna. This isolation ceased during the late Neogene after the formation of the Isthmus of Panama, resulting in an event known as the Great American Biotic Interchange (GABI). In this study, we investigate biogeographic patterns in South America, just before or when the first immigrants are recorded and we review the temporal and geographical distribution of fossil mammals during the GABI. We performed a dissimilarity analysis which grouped the faunal assemblages according to their age and their geographic distribution. Our data support the differentiation between tropical and temperate assemblages in South America during the middle and late Miocene. The GABI begins during the late Miocene (~10-7 Ma) and the putative oldest migrations are recorded in the temperate region, where the number of GABI participants rapidly increases after ~5Ma and this trend continues during the Pleistocene. A sampling bias toward higher latitudes and younger records challenges the study of the temporal and geographic patterns of the GABI. [ABSTRACT FROM AUTHOR]

A new species of dasypodid armadillo (Xenarthra, Cingulata),Anadasypus aequatorianus, from the late Miocene of Ecuador is described. The remains were collected in sediments of the Letrero Formation, Nabón Basin, which is part of several intermontane basins related to Andean uplift. The genus represents the oldest record of Dasypodini, which also encompassesPropraopus(Pleistocene–early Holocene) andDasypus(?Miocene–Recent). The new species is based on several osteoderms, which show more derived features thanAnadasypus hondanus, from the middle Miocene of Colombia. In order to test the affinities ofA. aequatorianuswithin Dasypodini, we conducted a cladistic analysis of 24 morphological characters for 10 taxa. The most parsimonious tree supports the generic attribution of the new species and placesAnadasypusbasal toPropraopusandDasypus, agreeing with the stratigraphic evidence. The faunas from tropical Andean areas differ noticeably from the better-known assemblages of the classic South American sequences. In the case of dasypodines, their geochronological distribution shows that they were historically restricted to tropical and subtropical environments and the main cladogenetic events of the group probably occurred at lower latitudes. In this context, the taxon described herein fills important temporal and geographic gaps of early Neogene armadillos from intertropical areas.http://www.zoobank.org/urn:lsid:zoobank.org:pub:9DC76603-D831-4E68-BE55-90113228E0F4 [ABSTRACT FROM AUTHOR]

Hydrochoerinae is a clade of caviomorph rodents broadly distributed in South America, which includes the maximum body size recorded among extant rodent taxa. The most basal forms of this group are an assemblage of small to medium body size extinct taxa with a plesiomorphic dentition, traditionally clustered in the group cardiomyines. One of the oldest known cardiomyine isProcardiomys martinoi(Chasicoan South American Land Mammal Age SALMA; early late Miocene), which was known only from the holotype, a fragmentary palate with the left and right molar series. New mandibular remains from the Arroyo Chasicó Formation (Chasicoan SALMA) are described and identified here as belonging toP. martinoibecause they share a unique combination of characters (as well matching in size) with the upper dentition of the holotype. These materials help in critically reviewing the taxonomic identification of the mandibular remains previously assigned toProcardiomysand allow testing the phylogenetic affinities of this taxon within Caviidae.P. martinoiis depicted as one of the most basal forms of Hydrochoerinae, placed basally on the lineage leading to extant capybaras after the split between the common ancestor ofKerodonandHydrochoerus. http://zoobank.org/F60356E0-CB8E-48C2-BF86-429E347A9579 [ABSTRACT FROM PUBLISHER]

This work describes the first record of a fossil anuran from the Neogene of Chile, found in miocene outcrops of the Río Pedregoso Member of the Cura-Mallín Formation, near the town of Lonquimay, Araucanía Region. The material consists of a distal half of left humerus and the proximal half of a radioulnae preserved in natural articulation. These elements present several similarities with extant members of Rhinella , which allow to confer the specimen to this genus. These similarities are the greater development of the ulnar epicondyle with respect to the radial, which may also have a great development of the medial crest, and the presence of a lateral crest and a humeral head slightly laterally displaced from the shaft of the diaphysis. Rhinella is a well-represented genus in the current batrachofauna of South America, but with a poor fossil record. The finding represents the southernmost fossil record of Bufonidae in South America for the Miocene. This discovery increases the knowledge about the distribution of the members of Rhinella during this epoch. • This works presents the southernmost fossil record of Bufonidae for the Miocene in South America. • This finding corresponds to the first record of an Anuran fossil in the Neogene of Chile. • This discovery increases the knowledge about the distribution of Bufonidae during the Miocene. [ABSTRACT FROM AUTHOR]

Abstract: Field, geochemical, geochronological, biostratigraphical and sedimentary provenance results of basaltic and associated sediments northern Colombia reveal the existence of Middle Miocene (13–14 Ma) mafic volcanism within a continental margin setting usually considered as amagmatic. This basaltic volcanism is characterized by relatively high Al2O3 and Na2O values (>15%), a High-K calc-alkaline affinity, large ion lithophile enrichment and associated Nb, Ta and Ti negative anomalies which resemble High Al basalts formed by low degree of asthenospheric melting at shallow depths mixed with some additional slab input. The presence of pre-Cretaceous detrital zircons, tourmaline and rutile as well as biostratigraphic results suggest that the host sedimentary rocks were deposited in a platform setting within the South American margin. New results of P-wave residuals from northern Colombia reinforce the view of a Caribbean slab subducting under the South American margin. The absence of a mantle wedge, the upper plate setting, and proximity of this magmatism to the trench, together with geodynamic constraints suggest that the subducted Caribbean oceanic plate was fractured and a slab tear was formed within the oceanic plate. Oceanic plate fracturing is related to the splitting of the subducting Caribbean Plate due to simultaneous subduction under the Panama-Choco block and northwestern South America, and the fast overthrusting of the later onto the Caribbean oceanic plate. [Copyright &y& Elsevier]

The extent to which animal lineages achieve large body size, a trait with broad advantages in competition and defence, varies in space and time according to the supply of (and demand for) resources, as well as the magnitude and effects of extinction. Using the maximum sizes of shallow-water marine shell-bearing molluscs belonging to nineteen guilds (groups of species with similar habits and food sources) in seven temperate regions from the Early Miocene to the Recent, the present study examined the controls on productivity and predation that enable and compel large size to evolve. The North Pacific (especially its eastern sector) has been most favourable to large-bodied species from the Pliocene onward. Large productive kelps (Laminariales) evolved there in conjunction with herbivorous mammals, setting the stage through positive feedbacks between production and consumption for the evolution of large molluscan herbivores and suspension-feeders. The evolution of bottom-feeding predatory mammals together with other large predators created intense selection for large molluscan sizes. Very large molluscs in the Early Miocene were concentrated in the southern hemisphere, especially among metabolically passive species. Extinctions, which preferentially targeted the largest members of guilds in most regions, were more numerous in the southern hemisphere and the North Atlantic than in the North Pacific. Minimal disruption, together with the early evolution of metabolically-active consumers and the positive feedbacks they engendered, accounts for the evolution of molluscan gigantism in the North Pacific. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ••, ••-••. [ABSTRACT FROM AUTHOR]

Abstract: Hallucinogenic or toxic species of Brunfelsia (Solanaceae: Petunieae) are important in native cultures throughout South America, and the genus also contains several horticulturally important species. An earlier morphological revision of the c. 50 species recognized three main groups, one consisting of the 23 Antillean species, another of southern South American and Andean species, and a third of species from the Amazon Basin and Guiana Shield. Based on plastid and nuclear DNA sequences from up to 65 accessions representing 80% of the species, we generated a phylogeny and a calibrated chronogram for Brunfelsia to infer clade expansion and shifts in pollinators and fruit types. Brunfelsia flowers offer nectar, and attract lepidoptera, hummingbirds, or bees; the fruits are dry or fleshy. Our results imply that Brunfelsia is 16–21Myr old and entered the Antilles from South America early during its history, with subsequent expansion along the island arc. The ancestor of the Antillean clade was hawk-moth-pollinated and had fleshy capsules, perhaps facilitating dispersal by birds. The only shift to hummingbird pollination occurred on Cuba, which also harbors the largest single radiation, with 11 species (10 included in our study) that apparently arose over the past 4Myr. Jamaica, Hispaniola, and Puerto Rico each sustained smaller radiations. The data also reveal at least one new species. [Copyright &y& Elsevier]

South American native ungulates include extinct taxa that evolved within the geographical context given by the isolation of South America during most of the Cenozoic. The ungulates (orders Notoungulata, Litopterna and Astrapotheria) of the Santa Cruz Formation (late Early Miocene) are particularly interesting for paleobiological studies due to their diversity, richness and quality of preservation of the specimens. The body mass estimation of extinct species is one of the basic biological attributes for paleobiological reconstructions. The most common way to estimate body mass from fossils is using linear regression. Here, we used geometric morphometric techniques in order to estimate their body mass. We used regressions based on centroid size of 3D craniomandibular landmark configurations, including extant ungulates (their size and ecological relatives). Cases were weighted to maximize the taxonomic evenness. A broad body size range was recorded. The highest predictive power is obtained with those functions derived from the highest taxonomic and ecological diversity. The highest taxonomic richness corresponds to masses below 100 kg. Among Notoungulata, typotheres ( Hegetotheriidae + Interatheriidae) vary from 1 to less than 10 kg, while the smaller toxodontid reached 100 kg and the larger 500 kg. Litoptern proterotheriid body masses vary from 10 to 50 kg, and macraucheniids surpass 100 kg. The astrapotheres ( Astrapotheria) reached (or even surpassed) 1000 kg, being the only megamammal in the Santacrucian ungulate assemblage. [ABSTRACT FROM AUTHOR]

Abstract: Octodontoidea is the most diverse group of caviomorph rodents. The systematics of most of the fossil representatives has been essentially based upon dental characters. Described here is an almost complete skull with dentition assigned to Prospaniomys Ameghino based upon its dental morphology. The specimen comes from the Sarmiento Formation at Pampa de Gan Gan (central Patagonia, Argentina), assigned to the Colhuehuapian SALMA (early Miocene). The most remarkable features are in the posterior portion of the skull, some of them shared with the modern octodontids and interpreted as specialized by previous authors, which contrast with the generalized dental morphology. These combined features were not previously known in other octodontoids. The comparisons with other fossil and extant members of the superfamily suggest that the characters traditionally used to associate Prospaniomys with the echimyids are very probably plesiomorphies. Prospaniomys would represent an early diverging lineage more closely related to modern octodontids than to echimyids, in which cranial structures evolved more rapidly than dental and mandibular ones. [Copyright &y& Elsevier]

Abstract: We construct a topographic datum across the central Andes between 18°S and 22°S using extensive, well-preserved paleosurfaces that span the entire range. This datum, combined with estimates of topographic change from paleoaltimetry in the Altiplano and geomorphic relief generation estimates from the plateau flanks allow us to reconstruct the paleo-topography of the range at ~10 Ma. Using the 10 Ma topography we explore which geophysical processes can create the observed topographic change over the <4 Ma period between 10 and 6 Ma. Our results indicate that loss of a dense lithospheric root, and possibly contemporaneous crustal flow, are the most likely processes that produced the observed plateau-wide topographic change. Raising the plateau purely by late Miocene crustal thickening would require shortening rates four times greater than those reported for the Cenozoic. [Copyright &y& Elsevier]

The fossil record of Pediastrum Meyen (Chlorophyceae) in southern South America is revised and 10 species/varieties are recognised within the genus. Previously published material is identified and new data are included. The oldest and most widespread variety for the region is P. boryanum var. boryanum, which appears in the Late Cretaceous age. P. tetras is recorded in the Early Eocene in Patagonia. P. boryanum var. brevicorne, P. boryanum var. longicorne, P. duplex, P. integrum, P. kawraiskyi, P. leonensis, P. mustersii and P. simplex are present in numerous Miocene assemblages. Assemblages of different species and mass production episodes are also detected in the fossil record. New examples of the value of Pediastrum species as paleoenvironmental markers are presented. [ABSTRACT FROM AUTHOR]

We report the oldest fossil condor (Vulturidae) from South America and the first from the Pisco Formation (14.0-2.0 Ma) of Peru, described herein as Perugyps diazi new genus and species. The Pisco Formation, exposed on the southern coast of Peru, has produced well-preserved and abundant marine and terrestrial vertebrate fossils from the late Miocene/early Pliocene (6.0-4.5 Ma) Montemar and Sacaco Sur localities, from where P. diazi was recovered. The new condor adds to our knowledge on the evolution and biogeographic distribution of New World vultures. The age of this new species supports the hypothesis that condors probably evolved in North America and entered South America by the late Miocene/early Pliocene. We believe it is likely that the first condors to reach South America probably did so via a coastal corridor along the western side of the Andes where they became part of the diverse coastal fauna in southern Peru. [ABSTRACT FROM AUTHOR]

The past ∼25 m.y. of geologic history in the northern ∼300 km (∼33°-36°S) of the Andean Southern Volcanic Zone has seen waxing and waning magmatic production rates and episodic eastward relocation of arc segments accompanied by abrupt chemical changes in the magmas. These changes can be linked to episodes of crustal thickening at times of backarc thrusting and to peaks of subduction erosion of forearc crust and mantle lithosphere at times of frontal-arc migration to the east. The magmatic-tectonic coupling is well seen in the history—enhanced by 28 new K-Ar ages, >160 major and trace element analyses, and Sr, Nd, and Pb isotope analyses—of a west to east transect through the El Teniente copper district near 34°S. The temporal trends in magmatic chemistry in this transect are like the well-documented south to north trends in Pleistocene to Holocene volcanic centers of the Southern Volcanic Zone, and both can be linked to the same events. The magmatic changes require differences in magma source regions as shown by isotopic data and in depths of crustal magma generation/fractionation as shown by pressure-sensitive trace element distributions. "Adakitic" magmas in the region are attributed to a combination of melting the base of thickened lower crust and crust entering the mantle through subduction erosion. Subduction erosion is argued to peak in episodes of frontal-arc migration at ca. 19-16 Ma and ca 7-4 Ma. The combined effects of crustal shortening and forearc truncation in the past 20 m.y. near 34°S have led to the loss of ∼170 km of crustal width. The liming and arc length over which these events occurred show that subduction of the Juan Fernández Ridge on the Nazca plate cannot have been the major driving force. The history of the region shows the importance of non-steady-state processes in arc-magma production and the necessity of studying arc systems over millions, not tens of thousands, of years. [ABSTRACT FROM AUTHOR]

The late Miocene Urumaco Formation of Venezuela has one of the richest and ecologically diverse crocodylian fossil faunas of the Cenozoic of South America. This diversity includes several different genera and species of crocodylians that held many distinct ecological niches, such as those of generalist predators, durophagous predators, giant predators and longirrostrine piscivorous, among others. This paper offers a significant addition to this already remarkable fauna by describing the first occurrence of Acresuchus pachytemporalis Souza-Filho et al.,2018 for the Urumaco Formation. This record consists of the specimen MCNUSB-PB-02FU-RS43, which is a posterior portion of the skull, consisted mostly by the skull table and the braincase, with incomplete mandibular rami associated. The specimen also represents the first occurrence of A. pachytemporalis outside the late Miocene Solimões Formation of Brazil, from which it has been originally described. As such, the occurrence of A. pachytemporalis in the Urumaco Formation recorded by this contribution is another evidence of the large taxonomical and paleoecological similarity between the crocodylian faunas of this unit and the Solimões Formation, which share many similar taxa at generic and specific levels and exhibit similar ecological niches being hold by fossil crocodylians. • The first occurrence of Acresuchus pachytemporalis in Venezuela is presented. • Acresuchus pachytemporalis is an unusual crocodylian with "horn-like" eminences. • It is the first occurrence of the taxon outside of Brazil, where it was discovered. • Our knowledge on the anatomy and geographic distribution of the taxon is increased. • A review of the fossil crocodylian fauna of northern South America is provided. [ABSTRACT FROM AUTHOR]

The Pirabas Formation (early to middle Miocene) from the equatorial margin of North Brazil is characterized by a shallow-marine carbonate platform with high fossil diversity and abundant micro- and macrofossil remains. The Pirabas Formation represents a unique carbonate system along the Atlantic margin of South America that developed before the onset of the Amazon delta. We studied the palaeontology and lithofacies of outcrops of the uppermost Pirabas Formation and found that was deposited in a coastal marine environment with marginal lagoons under the influence of a tidal regime and tropical storms. The remains of calcareous algae, molluscs, crustaceans, echinoiderms, bryozoans, solitary corals, fish and marine mammals, together with foraminifera, ostracods and other marine microfossils, shaped a biogenic framework, that together with the post-depositional processes of dissolution of skeletal grains, is responsible for the mean packstone-floatstone porosity of 14.9%. The palaeontological framework and the petrophysical characterization of the carbonate rocks from the uppermost Pirabas Formation outcrop represent a baseline to interpret the entire Pirabas Formation in the subsurface stratigraphic sections (cores) of this important Neogene unit. Considering that carbonate rocks account for ~50% of oil and gas reservoirs around the world, this research provides a model for Neogene tropical carbonate deposits useful for carbonate petroliferous reservoirs in the Brazilian equatorial basins. • Microfossil assemblages suggest a middle Miocene age for the uppermost Pirabas Formation at the Atalaia outcrop. • The palaeoenvironment are characterized by coastal lagoons with mangrove forests and shallow inner platform. • Microfossil frameworks are responsible for the heterogeneity in the porosity values • The ultimate driver of the collapse of Pirabas carbonate production is still uncertaing • The Pirabas Formation could become a facies model for Neogene tropical carbonate deposits of the tropical Atlantic [ABSTRACT FROM AUTHOR]

Thirteen million years ago in South America, the Pebas Mega-Wetland System sheltered multi-taxon crocodylian assemblages, with the giant caiman Purussaurus as the top predator. In these Miocene swamps where reptiles and mammals coexisted, evidence of their agonistic interactions is extremely rare. Here, we report a tibia of the mylodontid sloth Pseudoprepotherium bearing 46 predation tooth marks. The combination of round and bisected, shallow pits and large punctures that collapsed extensive portions of cortical bone points to a young or sub-adult Purussaurus (approx. 4 m in total length) as the perpetrator. Other known crocodylians of the Pebas System were either too small at adulthood or had discordant feeding anatomy to be considered. The pattern of tooth marks suggests that the perpetrator attacked and captured the ground sloth from the lower hind limb, yet an attempt of dismembering cannot be ruled out. This discovery from the Peruvian Amazonia provides an unusual snapshot of the dietary preferences of Purussaurus and reveals that prior to reaching its giant size, young individuals might have fed upon terrestrial mammals of about the size of a capybara.

The first record of the knifejaw family Oplegnathidae in the Atlantic Ocean and in South America is reported. It comes from the early Miocene Gaiman Formation lowermost beds at the lower Ri´o Chubut valley, central-eastern Patagonia. Family Oplegnathidae does not occur in the Atlantic today, but it was widespread in comparison to other knifejaw fishes such as scarids and odacids. Several aquatic vertebrates were extirpated from the southern Atlantic Ocean in the late Neogene. This record establishes a minimal age (early Miocene) for the extirpation of the family Oplegnathidae in the Atlantic Ocean. [Copyright &y& Elsevier]

Premise of the Study: Climatic and geological changes have been considered as major drivers of biological diversification. However, it has been generally assumed that lineages retain common environmental affinities, suggesting a limited capacity to switch their climatic niche. We tested this assumption with a study of the evolution of climatic niches in the Neotropical tree genus Cedrela (Meliaceae). •, Methods: We combined distribution models of extant Cedrela with a dated molecular phylogeny based on one nuclear (ITS) and three plastid markers (psbA-trnH, trnS-G and psbB-T-N) to reconstruct the evolutionary dynamics of climatic niches. We calculated relative disparity of climatic tolerances over time to test for niche evolution within subclades or divergence between subclades and conservatism among closely related groups. Published fossil records and studies on paleosols were evaluated for the distribution and climatic conditions of extinct Cedrela. •, Key Results: The fossil record of Cedrela suggested a major biome shift from paratropical conditions into warm-temperate seasonal climates in the Early Oligocene of western North America. In the Miocene, Cedrela extended from North America (John Day Formation, Oregon, USA) to southern Central America (Gatún, Panama). Diversification in the early evolutionary history was mainly driven by changes in precipitation. Temperature had an increasing impact on ecological diversification of the genus from the Miocene onwards. Sister-species comparisons revealed that recent speciation events may be related to divergence of climatic tolerances. •, Conclusions: Our study highlights the complexity of climatic niche dynamics, and shows how conservatism and evolution have acted on different temporal scales and climatic parameters in Cedrela.