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The analysis of the ostracods from three boreholes (1AS-7D-AM, 1AS-8-AM, and 1AS-31-AM) drilled in Atalaia do Norte town, Amazonas State, Brazil, allowed to recognize 30 species and nine genera. Cyprideis is the most abundant and diverse genus and is represented by 19 species already identified for the Solimões Formation, besides two new species described herein: Cyprideis atalaiensis sp. nov. and Cyprideis dictyon sp. nov. Intraspecific morphological variability, as well as the presence of nodes and tubercles, are observed in some species of Cyprideis and interpreted as a response to the paleoenvironmental changes during the Neogene in western Amazon region. Keywords: Cyprideis, morphological variability, paleoenvironmental changes, western Amazonia.

This work deals the systematic and paleobiologic studies on malacostraca siluro-devonian in two outcrops of the Manacapuru Formation, located at Belo Monte site, Para state, Amazonas Basin. Were identified the taxa Paranebalidae indet. A and Paranebalidae indet. B, phyllocarids, as well as Stenasellidae indet. isopod. During the siluro-devonian times these malacostraceans were very rich and diverse, cosmopolitan, lived in all marine regions and common elements of the benthic life. The specimens had robust and articulated carapaces with fragmentation and abrasion low grades that suggest low energy during the burial and less time of permanence in the taphonomic active zone. The pleopods and uropod articulated in Stenasellidae indet. and the exopodit and pleonite articulated with the pleopod in Paraneballidae indet. B suggest stronger articulations or fast burial and catastrophic death of these elements of biocoenosis. The isolated exopodite of Paraneballidae indet. A reveals weaker articulations among the others epipodites and exopodites, as well as short distance transport before the final burial, due the preservation of delicate spines of posterior margin and therefore considered as an element of thanatocoenosis. The pattern of the fossiliferous record may be related to siliciclastic sediments in the rocks of Manacapuru Formation, which does not lead to accumulation of animals with poorly mineralized body.

Biostratigraphic analysis integrating spores-pollen and ostracods from boreholes 1AS-8-AM and 1AS-7D-AM, at Atalaia do Norte, Amazonas state, Brazil, allowed to infer Early to Late Miocene for studied sequences. Five palynological zones previously proposed for the Solimoes Formation were identified: Verrutricolporites (Early Miocene), Psiladiporites–Crototricolpites (late Early to early Middle Miocene), Crassoretitriletes (Middle Miocene), Grimsdalea (late Middle to Late Miocene), and Asteraceae (Late Miocene). At the same time, four ostracods (Cyprideis) zones were identified but with limits modified: C. sulcosigmoidalis (late Early to early Middle Miocene); C. caraionae (late Middle to early Late Miocene); C. minipunctata (late Middle to Late Miocene); and C. cyrtoma (early Late Miocene). Furthermore, a new ostracod zone, Cyprideis paralela interval zone (Late Miocene), is formally proposed. Two main bioevents of Cyprideis radiation, related to marine incursions, have been identified: one at late Middle Miocene/early Late Miocene (Grimsdalea zone) and another at Late Miocene (Asteraceae zone). This study attests the viability and importance of using multiple microfossil for more accurate dating and correlation between basins.

The genus Copytus Skogsberg, 1939 was erected based on C. caligula, recovered from bottom sediments of the South Georgia Island, Antarctica. However, we propose herein that Skogsberg’s species is a junior synonym of Cytherideis laevata Brady, 1880 also collected from Antarctica and, therefore, Copytus laevata (Brady, 1880) becomes the type species. The position of the genus Copytus in the family Neocytherideidae is discussed, and a new family is proposed. In addition, we consider the genus Neocopytus Külköylüoðlu, Colin & Kiliç, 2007 invalid, and some of its species are transferred to Copytus. Finally, two new species of Copytus are herein described, C. cuspidata sp. nov. and C. wuerdigae sp. nov., and their geographic, bathymetric and stratigraphic distributions are discussed.

How environmental change affects a species' phenotype is crucial not only for taxonomy and biodiversity assessments but also for its application as a palaeo-ecological and ecological indicator. Previous investigations addressing the impact of the climate and hydrochemical regime on ostracod valve morphology have yielded contrasting results. Frequently identified ecological factors influencing carapace shape are salinity, cation, sulfate concentrations, and alkalinity. Here, we present a thorough approach integrating data with the carapace outline and surface details of the ubiquitous Neotropical cytheroidean ostracod species Cytheridella ilosvayi, as well as several climatic and hydrochemical variables, in order to investigate a potential link between morphology and environmental conditions. A recent study previously demonstrated considerable biogeographical variation in valve morphology among Floridian, Mexican and Brazilian populations of this species. We hypothesize that the climatic differences between the regions it inhabits and associated differences in hydrochemical regimes have influenced valve morphology and eventually led to biogeographically distinctive groups. Generalized least-squares Procrustes analyses based on outline and structural features were applied to the left and right valves of adult females and males. The analyses identified relative carapace length and shape symmetry as most important morphological characteristics representing shape differences across all datasets. Two-block partial least-squares analyses and multiple regressions indicate strong relationships between morphological and environmental variables, specifically with temperature seasonality, annual precipitation and chloride and sulfate concentrations. We suggest that increased temperature seasonality slowed down growth rates during colder months, potentially triggering the development of shortened valves with well-developed brood pouches. Differences in chloride and sulfate concentrations, related to fluctuations in precipitation, are considered to affect valve development via controlling osmoregulation and carapace calcification. The factors identified by our analyses represent hitherto unknown drivers for ostracod ecophenotypy in other species and therefore suggest that environmental predictors for morphological variability are not consistent across non-marine ostracods.

Geometric morphometric analyses were performed on the Neotropical ostracod Cytheridella including recent populations from Florida, Yucatan, Colombia, and Brazil. Generalized least-squares P...

Several studies have reported Miocene shallow-marine incursions in the Pebas Megawetland system (Western Amazonia) based on paleontological and sedimentological evidence. Only a few publications restricted to Middle and Late Miocene fossils outcropping in the Iquitos (Peru), Benjamin Constant and Eirunepe (Brazil) areas have provided isotopic evidence to test these incursions. In this study, we present new carbon, oxygen, and strontium (87Sr/86Sr ratios) isotopic data of macrofossils (pacu and ray teeth, crab claws and oysters), and microfossils (ostracods and foraminifera) from reported lower to lower upper Miocene sedimentary rocks of Western and Eastern Amazonian (Peru and Brazil), mainly from shallow-marine deposits. It was also analyzed present-day organisms from distinct environments (beach, sea, riverine, and estuary) and compared these results with Miocene fossils. While C and O isotopic compositions indicate that Western Amazonia fossils display an isotopic composition similar to the present-day continental, limnic and riverine, environments (−17‰ to −5.61‰ for δ13C and − 10.14‰ to −1.92‰ for δ18O), Eastern Amazonia fossils display C and O isotopic compositions comparable to those from seawater environments (−2.53‰ to −0.72‰ for δ13C and − 4.85‰ to −1.76‰ for δ18O). We further used the 87Sr/86Sr isotopic composition of the fossils to estimate paleosalinity conditions. The 87Sr/86Sr isotopic compositions indicates that Eastern Amazonian water bodies of the Pirabas Formation (Marajo Basin) varied from mesohaline to marine conditions. In contrast, Early Miocene Western Amazonian water bodies of the Pebas Megawetland System (PMWS) are characterized by freshwater conditions. Nonetheless, in Middle and Early Late Miocene, oligohaline conditions are found in the Peruvian part of the PMWS. Paleosalinity estimates of the Brazilian part of the PMWS are less constrained and might indicate a salinity range between freshwater or oligohaline conditions. Our isotopic data suggest the PMWS was occasionally submitted to oligohaline conditions during Middle and Early Late Miocene shallow-marine incursions. We suggest that Miocene shallow-marine incursions in Western Amazonia at this time were characterized by transitional paleoenvironments, reconciling isotopic, sedimentological and paleontological evidences.

Micropalaeontological studies of borehole cores 1AS-7D-AM and 1AS-8-AM, from Atalaia do Norte, Amazonas state, Brazil, support previous evidence for Miocene marine ingressions in Western Amazonia. Three marine incursion events are recorded: the first in the Early/early Middle Miocene (in both cores), the second in the late Middle/early Late Miocene (1AS-8-AM), and the third in the Late Miocene (1AS-7D-AM). The first event is characterized by exclusively mangrove taxa, and the last two present a mixture of marine, fresh, and brackish water taxa. However, at the end of the third event an increase of fluvial influence is demonstrated by the predominance of freshwater taxa. These marine incursions reached the study area through narrow and geographically limited connections, controlled by the tectonic setting, at a time between the Early/early Middle Miocene and late Middle/Late Miocene. Thereafter, fluvial conditions were reestablished before Pliocene times.

Background The Neotropics are considered to represent one of the most biologically diverse areas on Earth. Nonetheless, many species are assumed to have widespread distributions and occur in the entire Neotropical range. However, many freshwater invertebrates such as ostracods challenge this contradiction since they live in discrete habitats and possess no active dispersal abilities. The freshwater ostracod Cytheridella is a prime example for this paradigm. From three extant species, only one is described to occur ubiquitously within the Neotropics. Examination of morphological variability is the prerequisite for identification of environmentally induced variations, estimation of inter- and intraspecific variability, and, ultimately, the distinction of species. This study focuses on the quantitative investigations of the appendages of Cytheridella from several living populations sampled in Florida, Mexico, Colombia, and Brazil. Results The morphological traits including podomere ratios and limb-limb ratios, showed that the largest variability occurs at the antennae, and proved a geographical structure. Soft parts reflect the morphological divergence of regional Cytheridella priorly demonstrated by valves shape variability. Additionally, allometric coefficients, limb dimensions and body proportions revealed sexual and female biased size dimorphism. Large variability ranges of A-1 juveniles with reproductive anlagen could be the result of temporary deformations due to imminent moulting. Conclusion The geographical structure in the morphological variability allows the conjecture how widespread (freshwater invertebrate) species in the Neotropics may have arisen. Passive dispersal via e.g., birds can constitute the maximum ranges of species. If a population has adapted to local ecological conditions and may have occupied all available niches it may impede colonisation through (occasionally) other species. Relatively recent speciation(s) could explain why morphological divergence is not recognizable in qualitative investigations.

Ostracods from the Upper Oligocene to Lower Miocene Pirabas Formation, Northeastern Amazonia, Pará State, Brazil were examined from one subsurface and four outcrop sections. A total of 119 species were recognized and are illustrated; another 53 species were left in open nomenclature. Twenty-seven of the species are common to the Neogene of Caribbean, another two species are known from areas other than the Caribbean, and one species was already described from the studied unit. This study provides a robust taxonomic database for paleoenvironmental, biostratigraphic and paleogeographic studies and contributes to the knowledge of the paleodiversity of Neogene Ostracods from the Southwestern Atlantic.

The taxonomic study of brachiopods (Family Discinidae) from the upper part of the Manacapuru Formation (Lochkovian), south border of the Amazonas Basin, Brazil, allowed to recognize’ five species of Orbiculoidea: O. baini, O. bodenbenderi, O. excentrica, and two new species described herein: O. xinguensis sp. nov. and O. katzeri sp. nov. Besides, O. baini, O. bodenbenderi, and O. excentrica are recorded for the first time in the Manacapuru Formation, and in Northern Brazil, being the oldest records (Lochkovian) of these species in South America too. Their presence in the region can be explained by two reasons: the proximity of the Amazonas Basin, located in northwest Gondwana, during the Early Devonian to the continent of Laurasia (where are recorded most occurrences of Orbiculoidea during the Silurian), favoring the specific interchange between these two geographic regions; and the global sea level rise during this time, which flooded a large part of northwestern Gondwana, resulting in the presence of shallow seas in the Amazonas Basin, represented by marine sediments in the upper part of the Manacapuru Formation. These conditions promoted the colonization of inarticulate brachiopods during the Early Devonian in the north of Brazil. The discinoids identified in the strata of the Manacapuru Formation are typical of shallow marine environments, supporting previous interpretations for the upper part of this unit.

Perissocytheridea Stephenson is characteristic of brackish water facies. In 57 samples from the Upper Oligocene to Lower Miocene, from five localities, Pirabas Formation, Para State, Brazil eleven species have been identified. Among these species, four are new reports: Perissocytheridea punctoreticulata n. sp., Perissocytheridea largulateralis n. sp., Perissocytheridea colini n. sp. and Perissocytheridea pirabensis n. sp.; five species in open nomenclature: Perissocytheridea sp. 1, P. sp. 2, P. sp. 3, P . sp. 4, and P. sp. 5 and two species left in “aff.” abbreviation: Perissocytheridea aff. Perissocytheridea pumila and Perissocytheridea aff. Perissocytheridea brachyforma subsp. excavata . The distributional pattern of the Perissocytheridea combined with the occurrence of foraminifera Elphidium and Ammonia in the studied sections supports the presence of the brackish water facies to the respective layers. Their quantitative variation through the studied sections indicate more than one phase of salinity reduction (about >5 and

Material for all seven South American species of late Oligocene and Miocene scutelliform, non-lunulate sand dollars (Echinoidea: Clypeasteroida) was examined, resulting in revision of several taxa, and description of a new family, Placatenellidae n. fam., to house Placatenella n. gen. and Camachoaster n. gen. Known only from the state of Pará, Brazil, and previously described as a member of Abertella Durham, 1953, A. complanata Brito, 1981 is redescribed on the basis of analysis of the holotype and subsequently described material from the same region. A. complanata is removed from synonymy with A. pirabensis (Marchesini Santos, 1958), and transferred as the type species of Placatenella n. gen. A new taxon, Camachoaster n. gen., is described to hold C. maquedensis n. sp. The Abertellidae Durham, 1955 is revised and the concept of the genus Abertella restricted to include only those forms with a posterior notch and all interambulacra discontinuous, including A. pirabensis, which is redescribed from the only known specimen, confirming that this species lacks any trace of an anal lunule but possesses features fully congruent with its placement in Abertella. Iheringiellidae n. fam. is established to house the common but taxonomically challenging taxon, Iheringiella Berg, 1898. New data on the occurrence and location of the types of Iheringiella are discussed, and comments on the status of Eoscutella mirandae Parma, 1985 provided. A tabular key to all seven South American non-lunulates is given, along with discussion of the relationship between the posterior notch and the anal lunule. Fil: Mooi, Rich. California Academy Of Sciences; Estados Unidos Fil: Martinez, Sergio. Universidad de la República; Uruguay 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: Feijo Ramos, María Inés. Museo Paraense Emilio Goeldi; Brasil

Duas novas espécies de ostracodes, Eucypris lobatoi sp. nov. e Potamocypris taubatensis sp. nov., são propostas neste trabalho. Este é o primeiro registro fóssil destes gêneros no Brasil, cujas espécies identificadas ocorrem em duas fases distintas do Paleolago Tremembé. Eucypris lobatoi sp. nov. ocorre durante a fase mais antiga e estável do paleolago, enquanto Potamocypris taubatensis sp. nov., na fase mais recente e instável. Estes dados corroboram uma interpretação paleolimnológica prévia baseada em ostracodes que sustenta uma tendência de raseamento do paleolago durante o final da deposição da Formação Tremembé. Two new Oligocene ostracod species, Eucypris lobatoi sp. nov. and Potamocypris taubatensis sp. nov., are herein proposed. This is the first fossil record of these genera in Brazil, and the species identified occur in two distinct phases of the Tremembé Paleolake. It is assumed that Eucypris lobatoi sp. nov. has lived in the oldest and more stable phase of the lake, Potamocypris taubatensis sp. nov., in the youngest and more unstable phase. These data support a previous ostracod-based paleolimnological interpretation which sustains a shallowing trend in the paleolake during the final deposition of the Tremembé Formation.

The faunas of the highly fossiliferous Pirabas Formation belong to the southern part of the biogeographical unit known as "Neogene Tropical America". This unit developed prior to the closure of the Central American Seaway by the Isthmus of Panama. Until now, the age of the Pirabas Formation was inferred only from biostratigraphy. The Sr-isotope (87Sr/86Sr) values of pectinid shells from the Pirabas Formation show that most parts of this unit were deposited during the Late Burdigalian (about 16-17 Ma ). This result does not contradict biostratigraphic data and it constrains the age of the Pirabas Formation more tightly than do previous estimates of age, it for future, more precise biogeographical comparisons. Fil: Martinez, Sergio. Universidad de la República; Uruguay Fil: Feijó Ramos, María Inês. Museo Paraense Emilio Goeldi; Brasil Fil: McArthur, John M.. University College London; Estados Unidos 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: Thirlwall, Matthew F.. Royal Holloway University Of London; Reino Unido

The study of the subfamily Cytheropterinae from the southern Brazilian continental shelf reveals the presence of four genera and nine species, including two newly described (Cytheropteron sudatlanticum sp. nov., Loxoreticulatum pulchrum sp. nov.) and two left in open nomenclature (Cytheropteron sp. and Kangarina sp.). All of these species are restricted to the southern part of the Southwest Atlantic Ocean and do not extend beyond the coast of Rio de Janeiro, Brazil. Three of these species (Oculocytheropteron micropunctatum, O. reticulatum, O. macropunctatum) extend beyond the southern limit of the Brazilian Province (36°S), while the others occur inside the limits of the Brazilian Province (36°S–22/21°S). The genus Loxoreticulatum, a well-known ostracod taxon from the Antarctic Peninsula, southern Argentina and Falkland (= Malvinas) Islands, is herein reported for the first time from offshore Brazil.

Sixty-five ostracode species belonging to 41 genera and 17 families were recorded in the outer shelf and upper slope off Rio Grande do Sul and Santa Catarina states, southernmost Brazil, between 100 and 586 m water depth interval. The ostracode occurrences are hypothesized to be influenced by both, the coastal waters and the Antarctic Intermediate Water (AAIW). The taxonomy of some species of Bradleya Hornibrook, 1952, Legitimocythere ColesWhatley, 1989 and Henryhowella Puri, 1957 previously described in the same study area is revised. Bradleya gaucha sp. nov., Legitimocythere megapotamica sp. nov., Apatihowella acelos sp. nov., Apatihowella capitulum sp. nov., Apatihowella besnardi sp. nov., Apatihowella convexa sp. nov., and Aversovalva tomcronini sp. nov. are herein proposed. Trachyleberis aorata BergueCoimbra, 2008 is reassigned to the genus Legitimocythere and Bradleya pseudonormani Ramos et al., 2009 has its diagnosis emended. Bythocypris praerenis Brandão, 2008 is considered a junior synonym of Bythocypris kyamos Whatley et al., 1998a. Apatihowella JellinekSwanson, 2003 and Legitimocythere species have well-defined bathymetric distributions and are potential paleoceanographic markers for the Quaternary in the Southern Brazilian Margin.

The present study is a further contribution to the systematic knowledge of the ostracods from the southern Brazilian continental shelf. Twelve species of Trachyleberididae are recorded, including the following six new taxa

Introdução

The genera Haplocytheridea and Cytheridea have Tethyan origins and a wide paleobiogeographic and stratigraphic distribution, ranging from the Cretaceous to Recent. Both of them have been recorded in northern South America, but only Cytheridea has been found in the northern Cretaceous basins of Brazil. The genus Haplocytheridea is recorded, for the first time, in the Early Miocene deposits of the Pirabas Formation of northern Brazil, from a 20 m-thick succession of carbonate and argillaceous rocks deposited in lagoonal and restricted platform environments. Among the ten Haplocytheridea species identified, four are new: H. variopunctata n. sp., H. sandbergi n. sp., H. pirabasensis n. sp. and H. sinuosa n. sp. In addition, three new species of Cytheridea are also described: C. coimbrai n. sp., C. pirabasensis n. sp. and C. purperae n. sp. The highest frequencies and abundances of both genera, in the studied section, are thought to be associated with nearshore to brackish water settings.

In Miocene times a vast wetland existed in Western Amazonia. Whereas the general development of this amazing ecosystem is well established, many questions remain open on sedimentary environments, stratigraphical correlations as well as its palaeogeographical configuration. Several outcrops located in a barely studied region around Eirunepé (SW Amazonas state, Brazil) were investigated to obtain basic sedimentological data. The observed deposits belong to the upper part of the Solimões Formation and are biostratigraphically dated to the Late Miocene. Vertically as well as laterally highly variable fine-grained clastic successions were recorded. Based on the lithofacies assemblages, these sediments represent fluvial deposits, possibly of an anastomosing river system. Sand bodies formed within active channels and dominant overbank fines are described (levees, crevasse splays/channels/deltas, abandoned channels, backswamps, floodplain paleosols). Lacustrine environments are restricted to local floodplain ponds/lakes. The mollusc and ostracod content as well as very light δ18O and δ13C values, measured on ostracod valves, refer to exclusively freshwater conditions. Based on palaeontological and geological results the existence of a long-lived lake (“Lake Pebas”) or any influx of marine waters can be excluded for that region during the Late Miocene., Highlights ► Around Eirunepé (Amazonia, Brazil) six outcrops were sedimentologically investigated. ► The sediments are of Late Miocene age and belong to the Solimões Formation. ► Lithofacies assemblages document a fluvial sedimentary environment. ► Molluscs, ostracods and stable isotopes refer to exclusively freshwater conditions. ► The existence of a long-lived lake or any influx of marine waters can be excluded.

Species composition in the present-day Amazonian heartland has an imprint of past marine influence. The exact nature, timing and extent of this marine influence, however, are largely unresolved. Here we use calcareous tests of foraminifera and marine palynomorphs from Miocene sediments in northwestern Amazonia to extend on current estimates for salinity ranges, paleoenvironments and paleogeography. Our samples mostly contain tests and/or organic linings of euryhaline (tolerant to a wide range of salinity) foraminifera of the genera Ammonia , Trochammina and Elphidium , with Ammonia being by far the dominant genus at all locations. Organic-walled dinoflagellate cysts (dinocysts), such as Spiniferites , Brigantedinium and Tuberculodinium vancampoae , are also common at a number of sites. This association of foraminifera and dinocyst taxa points at varying salinities, with aberrant forms of Ammonia indicating lower limits of 0–10 psu (practical salinity units) whereas dinocyst associations suggest more marine conditions. Such regional heterogeneity is common at the interface of shallow marine to freshwater environments, like estuaries. We conclude that during the early and middle Miocene marginal marine conditions reached at least 2000 km inland from the Caribbean portal. Global high sea level and fast subsidence in the sub-Andean zone are thought to be the controlling mechanisms of the marine incursions. Lowering of global sea level and a change in tectonic regime terminated the incursions in the course of the Plio-Pleistocene.

IDENTIFICATION AND PALEOENVIRONMENTAL SIGNIFICANCE OF THE OSTRACOD FAUNA FROM CODO FORMATION (NEOAPTIAN), EAST OF THE GRAJAU BASIN, MA, BRAZIL. The study of ostracods from sedimentary successions exposed in the east portion of the Grajau Basin, Maranhao State, related to Codo Formation, revealed a Neoaptian lacustrine fauna characterized exclusively by Harbinia and Candona represented by the species Candona sp., Harbinia micropapillosa (Bate), Harbinia angulata (Krommelbein & Weber), Harbinia sinuata (Krommelbein & Weber), Harbinia sp. aff. H. symmetrica (Krommelbein & Weber), Harbinia salitrensis (Krommelbein & Weber) and Harbinia sp. The stratigraphical distribution patterns of the ostracod palaeocommunities in the studied sections confirmed the occurrence of a cyclic depositional lacustrine environment, as assumed by previous faciological studies. These cycles are associated with events of expansion and contraction of the lake, characterized mainly as hipersaline, with shallow-water and very low oxygen levels. The sudden environmental changes caused by these events produced a monospecific occurrence of some resilient species, followed by a mass death.

Ostracods from an outcrop of the Solimoes Formation (southwestern Amazonas state, Brazil) are studied. One new species ( Cytheridella purperae sp. nov. ) is described, and six species endemic to the Neogene of western Amazonia ( Darwinula fragilis , Cyprideis pebasae , C. graciosa , C. longispina , C. lacrimata , and Cypria aqualica ) are reported, together with one unidentified species ( Cytheridella sp.). The fauna suggest a low-energy fluviolacustrine depositional setting, possibly with very low salinity. Using facies and ostracod data, the studied outcrop is compared with other Miocene deposits of western Amazonia.

A study of the family Cytheruridae in Recent sediments from the coast of northern Rio de Janeiro State revealed the presence of four new species: (Hemicytherura auriculata, Oculocytheropteron delicatum, Oculocytheropteron circumcostatum and Semicytherura caudata,) and four previously described species (Semicytherura rugosoreticulata Whatley, Chadwick, Coxill & Toy, 1988, Oculocytheropteron macropunctatum Whatley, Chadwick, Coxill & Toy, 1988, Oculocytheropteron reticulopunctatum Whatley, Chadwick, Coxill & Toy, 1988 and Paracytheridea bulbosa Purper & Ornellas, 1989). A further two species Cytheropteron sp. and Kangarina sp. are left in open nomenclature due to paucity of the material. The ecology and distribution of the fauna suggest that the presence of many of these species, which also occur in colder waters off the coast of Uruguay and Argentina, is probably due to the upwelling of the South Atlantic Central Water in this area.

This first analysis of the marine fish fossil record in the Caribbean region during the Neogene is based on comprehensive new faunal compilation lists at the generic level from basins of nine Central and South American countries during Miocene and Pliocene times. Joint ordination and classification techniques were used to analyze data comprising 236 genera and 346 species. Principal Component Analyses were used to calculate covariance and variance between localities. We identified four subprovinces, representing four different patterns. The subprovince of Venezuela shows distinct and unique features since the Neogene in the diversity of ecosystems represented. The Antillean subprovince has a western orientation and is composed of Jamaica, the Dominican Republic, and the Trinidad islands. The third subprovince combines Panama and Ecuador. It reflects the Pacific faunal influence into the proto-Caribbean and a characteristic benthopelagic fauna. The fourth subprovince is Costarican. Its nektonic fish fauna reflects the overprinting impact over the proto-Caribbean fish fauna mostly due to local paleoenvironmental changes (neritic, estuarine and deep water assemblages), whereby the overall composition of genera is largely not affected (except few lamnids, such as the giant-toothed white sharks and the wide-toothed mako shark). The results of the analyses are concordant with previous ones based on invertebrates and identified regions in need of study (e.g., Colombia, Nicaragua, Honduras, and Brazil).

O presente trabalho é parte de um projeto maior que pretende descrever os Ostracoda presentes na plataforma continental sul-brasileira, entre os estados do Rio de Janeiro e Rio Grande do Sul (aproximadamente 2.050 km de extensão), bem como interpretar o significado zoogeográfico de um total de 102 espécies. As famílias Pontocyprididae e Bairdiidae são representadas por quatro e duas espécies, respectivamente, sendo cinco novas: Argilloecia inflata, A. subacuta, Pontocypris? punctatus, Bairdoppilata sudbrasiliensis e Neonesidea? rotunda. Argilloecia parameridionalis Whatley et al., tem sua distribuição extendida para o norte. This work is part of a long-term project that attempts to describe the Ostracoda present in the southern Brazilian shelf between Rio de Janeiro and Rio Grande do Sul states (almost 2,050 km in length), and to assess the zoogeographical significance of a total 102 benthic species. In this paper the families Pontocyprididae and Bairdiidae have been identified with the description of five new taxa: Argilloecia inflata, A. subacuta, Pontocypris? punctatus, Bairdoppilata sudbrasiliensis, and Neonesidea? rotunda. Argiloecia parameridionalis Whatley et al., is here recorded farther north than previous records.

The Miocene mega-wetland of western Amazonia holds a diverse, largely endemic ostracod fauna. Among them, especially the genus Cyprideis experienced a remarkable radiation. Micropalaeontologic investigations of a 400 m long sediment core (~62 km SW Benjamin Constant, Amazonia, Brazil) permitted a taxonomic revision of about two-thirds of hitherto described Cyprideis species. We evaluate the diagnostic value of shell characters and provide an extensive illustration of the intraspecific variability of species. Based on comparative morphology, the 20 recorded Cyprideis species are arranged in groups and subgroups. The “smooth” group comprises C . amazonica , C . kotzianae , C . kroemmelbeini , C . machadoi , C . multiradiata , C . olivencai , C . paralela and C . simplex ; the “ornate” group C . curucae nom. nov., C . cyrtoma , C . aff. graciosa , C . inversa , C . ituiae n. sp., C . matorae n. sp., C . minipunctata , C . munoztorresi nom. nov., C . pebasae , C . reticulopunctata , C . schedogymnos and C . sulcosigmoidalis . Five species have been revalidated, two renamed, two synonymised and two are new descriptions. Along with 10 further formally established species, for which a review is pending, Cyprideis keeps at least 30 endemic species in that region during Miocene times. Up to 12 Cyprideis species have been found to occur sympatrically, representing >90 % of the entire ostracod fauna. Ostracod index species enable a biostratigraphic allocation of the well succession to the Cyprideis minipunctata to Cyprideis cyrtoma biozones, corresponding to a late Middle to early Late Miocene age (late Serravallian–early Tortonian).

Este trabalho trata sobre a revisao sistematica dos gastropodes representantes da familia Architectonicidae na Formacao Pirabas. Foi confirmada a sinonimia de Architectonica granulatum (Lamarck) e A . intraornatum (White) com A . nobilis Roding, assim como invalidar A . eudaidelum (Maury), por tambem ser sinonima de A . nobilis , especie tipicamente marinha neritica, de salinidade normal, anfi-americana, mais abundante em latitudes baixas e que teve expansao biogeografica continua a partir do Mioceno. A espessura de suas conchas, ambiente e modo de vida, bem como suas feicoes preservacionais e ocorrencia associada a litofacies biocalcirrudito sugerem que os exemplares frequentes nas camadas tipicas do ambiente lagunar da sequencia Pirabas/Barreiras sejam aloctones, tendo sido transportados a partir do ambiente marinho franco pelos canais de mare por meio de ondas de tempestade.