Mioceno

Through the morphological changes observed in the cranial and facial remains of the Miocene hominoids, the evolutive lineage, from the primitive catarrhines from the Oligocene of the Fayum (Egypt) to the living hominoids, can be established. A lot of the distinctive traits of the actual orang-utan (Pongo) are already present in the African Lower and Middle Miocene kenyapithecines, from which appeared, on the one hand the
Sivapithecus-Pongo clade (primitive) and, on the other the Dryopithecus-Graecopithecus-African hominids (derived). The separation between these two clades began in Eurasia during the Middle Miocene (12.5 my) due to geographical and climatic changes

Resumo A ocorrência de braquiópodes no Neógeno da Bacia de Pelotas é conhecida desde 1862. A despeito disso, porém, estudos detalhados de sistemática e tafonomia ainda não existem. Investigações conduzidas meio século atrás indicaram que os braquiópodes poderiam ser atribuídos à espécie Bouchardia cf. zitteli, comum à Formação San Julian, Oligoceno Superior, Argentina. A revisão realizada indica, contudo, que a espécie presente é Bouchardia transplatina. Na porção uruguaia da Bacia de Pelotas, B. transplatina é conhecida na Formação Camacho, Mioceno. Em adição, pequenas conchas de braquiópodes foram recuperadas também de material de calha, de poços Petrobras (2PJ-1-RS, 2PN-1-RS e 2GA-1-RS), na porção continental da Bacia de Pelotas. Esses braquiópodes provêm de intervalo estratigráfico (130 a 150 metros) correspondente à Zona Henryhowella evax (Mioceno). A despeito do alto grau de dissolução das conchas, essas podem ser atribuídas, sem dúvida, a Bouchardia sp. Os dados acima são relevantes, pois: 1-Bouchardia possui afinidades com águas quentes (tropicais/subtropicais). Presentemente, formas viventes desse gênero habitam águas em latitudes de até 34°S, mas a maior abundância está em torno de 23°S; 2-embora ocorram em profundidades superiores a 200 metros, Bouchardia rosea (espécie vivente) é mais abundante em águas plataformais rasas, ricas em nutrientes; 3-a presença de Bouchardia, no Mioceno da Bacia de Pelotas indica que, pelo menos no intervalo da Zona Henryhowella evax, condições de águas quentes relacionadas à Corrente do Brasil, prevaleceram. Essa interpretação está de acordo com dados paleoeoceanográficos e paleoclimáticos, fornecidos por ostracodes e foraminíferos que co-ocorrem com os braquiópodes estudados.

La construcción de un centro comercial en el área metropolitana de Madrid, junto al río Manzanares, ha permitido documentar un yacimiento de micromamíferos miocenos.
Se ha estudiado en detalle la asociación de roedores, con el fin de determinar el contexto bioestratigráfico y paleoecológico del yacimiento, mediante su comparación con los yacimientos equivalentes de la Cuenca de Calatayud-Montalbán y de la propia Cuenca de Madrid. Se han recuperado 146 elementos dentales pertenecientes a los roedores: Megacricetodon primitivus, Megacricetodon vandermeuleni, Democricetodon moralesi, Armantomys aragonensis, Microdyromys koenigswaldi, Pseudodryomys ibericus y Heteroxerus rubricati. Representa un conjunto faunístico poco diverso caracterizado por la predominancia del género Megacricetodon, y la escasa representación de glíridos y esciúridos. El conjunto faunístico es correlacionable
con la parte superior de la biozona Db, siendo la primera ocasión que se reconoce en el municipio de Madrid. La asociación de roedores sugiere condiciones de mayor humedad y/o ambientes más cerrados, que en biozonas posteriores, biozonas Dc y Dd. Respecto a la Cuenca de Calatayud-Montalbán la asociación de Madrid podría representar condiciones de mayor aridez o ambientes más abiertos.

The Cerro de los Batallones (Los Batallones Butte) is located in the central-northern area of the Madrid Basin, central Spain. Nine vertebrates localities containing a large variety of mammals of Upper Vallesian Age (Late Miocene) have been found associated with the sediments forming the butte. From bottom to top, these sediments consist of magnesian lutite beds (Unit I), paleosols formed of sepiolite and opal (Unit II), and siliclastic, marlstone and carbonate beds (Unit III). The set of ERT profiles developed in ...

El estudio taxonómico de los foraminíferos planctónicos desde el Cretácico Superior (Maastrichtiense) al Mioceno Medio (Langhiense) ha permitido establecer una biozonación aplicable a las zonas subtropicales y templadas, ya que los cortes y sondeos estudiados se distribuyen por estas latitudes. Así mismo el estudio taxonómico de los microforaminfferos bentónicos del tránsito Paleoceno-Eoceno ha posibilitado la biozonación con este grupo y el estudio exhaustivo del evento paleoceanográfico del limite Paleoceno/Eoceno. Otros eventos tales como los asociados a los límites Oligoceno/Mioceno, Eoceno/Oligoceno y Cretácicofl'erciario también han sido estudiados en detalle, tratando de determinar la cronología de las extinciones y apariciones, y evaluando su potencial interés como estratotipos de límite.

A través de los cambios morfo16gicos observables en los restos craneofaciales y dentales de los hominoideos del Mioceno podemos establecer la línea evolutiva que conduce desde los primitivos catarrinos del Oligoceno de El Fayum (Egipto) hasta los hominoideos actuales. Muchas de las características distintivas del actual orangután (Pongo) ya se empiezan a perfilar en los kenyapitecinos del Mioceno inferior y medio africano, a partir de los cuales se originarán los clados Sivapithecus-Pongo (primitivo), por un lado, y Dryopithecus-Craecopithecus­homínidos africanos (derivado), por otro. La separación entre los dos clados se produjo en Eurasia durante el Mioceno medio (12,5 ma) debido a cuestiones geográficas y climáticas.

Two Miocene woods collected in “Arroyo Maderas” locality, Marques de Comillas municipality, Chiapas, collected by members of Paleobotany Laboratory of the Instituto de Geología, UNAM and the Eliseo Palacios Aguilera Paleontological Museum of Tuxtla Gutierrez, Chiapas, are described. Their wood structure have anatomical features that make them different from each other; however, they show affinity to the Humiriaceae and Lauraceae. In the first morphotype, the presence of simple perforated plate, spiral thickenings on vessel element walls element, presence or absence of chambered fibers, oil cells between in fibers, vessel-ray pitting of different sizes, body rays with procumbent cells in their body and upright or square cells in their tails, and idioblasts with cubic crystals, scanty and diffuse axial parenchyma strongly suggest in Lauraceae. In contrast, the presence of scalariform perforation plate, vasicentric tracheids, intervessel and vessel-ray pits similar in shape and size to...

The Cerro de los Batallones (Los Batallones Butte) is located in the central-northern area of the Madrid Basin, central Spain. Nine vertebrates localities containing a large variety of mammals of Upper Vallesian Age (Late Miocene) have been found associated with the sediments forming the butte. From bottom to top, these sediments consist of magnesian lutite beds (Unit I), paleosols formed of sepiolite and opal (Unit II), and siliclastic, marlstone and carbonate beds (Unit III). The set of ERT profiles developed in ...

ABSTRACT The Monte Hermoso Formation, cropping out at its type locality of Farola Monte Hermoso (Buenos Aires Province), is a classical fossiliferous unit of the South American Neogene, highlighted by the abundance and diversity of its vertebrate remains. However, its biostratigraphy and age have been largely debated, and numerous discrepancies and controversies have been stated. In this regard, the result of the analysis of new materials recovered from the different levels of this formation, following a strict control of stratigraphic provenance, is here reported. As well, the provenance of specimens of previous collections has been evaluated. The studied assemblage consists of Osteichthyes, Amphibia, Reptilia, Aves and Mammalia. These latter are the most numerous and belong to the Didelphimorphia, Polydolopimorphia, Rodentia, Notoungulata, Litopterna and Xenarthra. The recorded taxa suggest no important faunistic variations among the different levels of the Monte Hermoso Formation that would imply significant chronological differences, and hence, justify the recognition of two biostratigraphic units. The analysis of the first and last records as well as the taxa considered as exclusive, does not support the validity of the biozones of Trigodon gaudryi and Neocavia depressidens previously proposed. On this basis, a new scheme for the Monte Hermoso Formation at its type locality is proposed, including a new single biostratigraphic unit. This unit is the Eumysops laeviplicatus Range Zone, which represents the biostratigraphic base for the Montehermosan Stage/Age of the early Pliocene.

Two Miocene woods collected in “Arroyo Maderas” locality, Marques de Comillas municipality, Chiapas, collected by members of Paleobotany Laboratory of the Instituto de Geología, UNAM and the Eliseo Palacios Aguilera Paleontological Museum of Tuxtla Gutierrez, Chiapas, are described. Their wood structure have anatomical features that make them different from each other; however, they show affinity to the Humiriaceae and Lauraceae. In the first morphotype, the presence of simple perforated plate, spiral thickenings on vessel element walls element, presence or absence of chambered fibers, oil cells between in fibers, vessel-ray pitting of different sizes, body rays with procumbent cells in their body and upright or square cells in their tails, and idioblasts with cubic crystals, scanty and diffuse axial parenchyma strongly suggest in Lauraceae. In contrast, the presence of scalariform perforation plate, vasicentric tracheids, intervessel and vessel-ray pits similar in shape and size to...

Two Miocene woods collected in “Arroyo Maderas” locality, Marques de Comillas municipality, Chiapas, collected by members of Paleobotany Laboratory of the Instituto de Geología, UNAM and the Eliseo Palacios Aguilera Paleontological Museum of Tuxtla Gutierrez, Chiapas, are described. Their wood structure have anatomical features that make them different from each other; however, they show affinity to the Humiriaceae and Lauraceae. In the first morphotype, the presence of simple perforated plate, spiral thickenings on vessel element walls element, presence or absence of chambered fibers, oil cells between in fibers, vessel-ray pitting of different sizes, body rays with procumbent cells in their body and upright or square cells in their tails, and idioblasts with cubic crystals, scanty and diffuse axial parenchyma strongly suggest in Lauraceae. In contrast, the presence of scalariform perforation plate, vasicentric tracheids, intervessel and vessel-ray pits similar in shape and size to...

In this contribution we show the first termite nests fossil record presence from the Mesopotamian region of Argentina and its spatial distribution. At the same time taxonomic affinities and paleoenvironmental implications are discussed. The discovery takes place in the contact area between the base of the Toropí / Yupoí formations (late Pleistocene) and the top of the Ituzaingó Fm.

ABSTRACT The Monte Hermoso Formation, cropping out at its type locality of Farola Monte Hermoso (Buenos Aires Province), is a classical fossiliferous unit of the South American Neogene, highlighted by the abundance and diversity of its vertebrate remains. However, its biostratigraphy and age have been largely debated, and numerous discrepancies and controversies have been stated. In this regard, the result of the analysis of new materials recovered from the different levels of this formation, following a strict control of stratigraphic provenance, is here reported. As well, the provenance of specimens of previous collections has been evaluated. The studied assemblage consists of Osteichthyes, Amphibia, Reptilia, Aves and Mammalia. These latter are the most numerous and belong to the Didelphimorphia, Polydolopimorphia, Rodentia, Notoungulata, Litopterna and Xenarthra. The recorded taxa suggest no important faunistic variations among the different levels of the Monte Hermoso Formation that would imply significant chronological differences, and hence, justify the recognition of two biostratigraphic units. The analysis of the first and last records as well as the taxa considered as exclusive, does not support the validity of the biozones of Trigodon gaudryi and Neocavia depressidens previously proposed. On this basis, a new scheme for the Monte Hermoso Formation at its type locality is proposed, including a new single biostratigraphic unit. This unit is the Eumysops laeviplicatus Range Zone, which represents the biostratigraphic base for the Montehermosan Stage/Age of the early Pliocene.

The Cerro de los Batallones (Los Batallones Butte) is located in the central-northern area of the Madrid Basin, central Spain. Nine vertebrates localities containing a large variety of mammals of Upper Vallesian Age (Late Miocene) have been found associated with the sediments forming the butte. From bottom to top, these sediments consist of magnesian lutite beds (Unit I), paleosols formed of sepiolite and opal (Unit II), and siliclastic, marlstone and carbonate beds (Unit III). The set of ERT profiles developed in ...