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Copyright of Cuaternario y Geomorfología is the property of Cuaternario y Geomorfologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Comma shrimp, or cumaceans, are diverse benthic crustaceans, yet they are one of the groups with the poorest fossil record, hindering our understanding of the evolution of the group in deep time. Here, we describe a new species of fossil comma shrimp, Makrokylindrus itoi sp. nov., from the Plio‐Pleistocene of Japan. The singular fossil is exceptionally preserved, including details of the carapace, cuticle, and some appendages, and it represents the first known fossil of the family Diastylidae and only the fourth fossil crown group cumacean known to date. We suggest that the scarce and sparsely known fossil record of cumaceans likely reflects a lack of recognition due to their small size and unfamiliar anatomy, making fossil cumaceans easy to misidentify, be confused with crustacean larvae of unknown affinities, or be interpreted as fragments of other crustaceans (taxonomic bias), rather than a lack of fossilization potential (taphonomic bias). [ABSTRACT FROM AUTHOR]

Copyright of Geominas is the property of FUNDA-GEOMINAS. (Fundacion de Egresados d Amigos de la Escuela de Ingenieria Geologica y de Minas) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Los sistemas fluviales del Gran Chaco, América del Sur, constituyen un tipo de registro fluvial significativo para la cuenca de antepaís andina moderna. El mega-abanico fluvial del Salado-Juramento (MAFSJ), uno de los sistemas más grandes de Sudamérica, presenta características morfológicas y sedimentológicas distintivas. El MAFSJ, desarrollado por el desplazamiento del río Salado-Juramento hacia el sureste, presenta numerosos paleocauces en un patrón distributivo hacia el E desde su ápice en las Sierras Subandinas. En este trabajo se estudian atributos paleohidrológicos y la sedimentología de dos secciones ubicadas en paleocauces del área distal del MAFSJ, con el objetivo de generar información estratigráfica y sedimentológica de los rellenos de paleocauces que permita inferir su dinámica. De cada sucesión, se obtuvieron muestras de sedimentos para diferentes análisis: sedimentológicos (mineralogía y granulometría de sedimentos), y cronológicos. El cociente entre los atributos paleohidrológicos como la anchura del cauce-W y el espesor-T (W/T) presenta valores en un rango de 9,4 a 16,1 (media 12,75) para el área distal del MAFSJ. Estos valores indican cauces en cinta (ribbon channels). El relleno de los paleocauces estudiados está conformado por arenas muy finas a finas, con una mineralogía de arcillas y arenas consistente con los depósitos generados por el río Salado. Estos depósitos son cubiertos por niveles limo-arcillosos de carácter eólico. La geomorfología, los atributos paleohidrológicos, la sedimentología y los fechados numéricos, sugieren un paleodrenaje distributivo con cauces activos durante el MIS 3 (62–28 Ka AP). Se interpreta una fase de agradación fluvial durante el MIS 3, representada en gran parte por los rellenos de canales sinuosos que sugieren numerosos ríos divergentes en el área distal del MAFSJ. El sistema fluvial disminuye y domina la actividad eólica hacia el MIS 2, siendo cubierto por depósitos limo-arcillosos.

Here I reviewed the Pleistocene caviomorphs collected by Santiago Roth (collection from Catalog No. 5) and housed at the paleontological collection of the Paläontologisches Institut und Museum, Universität Zürich, Zurich (Switzerland). The fossils were found in Pleistocene strata from Buenos Aires and Santa Fé provinces (Argentina) during the late nineteenth century. The material includes craniomandibular remains assigned to Lagostomus maximus (Chinchilloidea: Chinchillidae), craniomandibular and postcranial (thoracic and sacral vertebra, left scapula, left femur, and right tibia) bones identified as Dolichotis sp. (Cavioidea: Caviidae), and a fragmented hemimandible and isolated tooth of Myocastor sp. (Octodontoidea: Echimyidae). Other rodent specimens from this collection (Ctenomys sp. and Cavia sp.) are possibly sub-recent materials. [ABSTRACT FROM AUTHOR]

One of the most abundant species of bivalves found on modern beaches and Quaternary deposits in the San Matías Gulf (Argentinian Patagonia, SW Atlantic Ocean) is Glycymeris longior. Its high abundance and broad geographical distribution turn G. longior into a target species for taphonomical studies. Here, we described the taphonomic signature registered on its shells from San Antonio Bay (San Matías Gulf, Río Negro). This study will contribute to future taphonomic comparisons in the SW Atlantic Ocean, as well as in other Quaternary deposits, and provide insight into the spatial variation of the taphonomic processes influenced by the environment. Glycymeris longior valves from the Holocene Punta Delgado deposits showed two taphonomic signatures whose shell assemblages were differentiated by fragmentation, rounding and cementation intensities. Shells from PD2018A and PD2018B (two sampling localities representing similar environments) were subject to continuous and low-energy water flow. Those remained in a low-intensity hydrodynamic sediment-water interface that would favor high shell cementation. On the other hand, shells from PD2016 were also subject to continuous but more energetic water flow. Those would remain in the taphonomic active zone for enough time to confer smooth edges and to be colonized by clionid sponges but not favorable enough for carbonate precipitation. The Punta Delgado site was interpreted as a protected area during the Holocene (last 4200 yrs.), similar to the modern one, but with differences in carbonate precipitation as the product of differences in water flow intensities. Finally, the high mechanical resistance of G. longior shells, together with its abundance and broad geographical distribution, turn this species into a suitable target taxon for further taphonomic and ecologic analyses and comparisons. [ABSTRACT FROM AUTHOR]

Copyright of Swiss Journal of Paleontology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

En el estado de Jalisco, localizado en el oeste de México, se encuentran yacimientos fósiles que abarcan desde el Cretácico inferior al Cuaternario. En este trabajo se presenta una lista sistemática del registro fósil de Jalisco, México, y se analiza la composición de su riqueza. Fue revisada la literatura global sobre el tema y consultadas las colecciones que poseen material fósil de la región. Se obtuvieron un total de 293 especies organizadas en tres reinos, seis phyla, 12 clases, 49 órdenes, 87 familias y 184 géneros. Un total de 67 especies (22,9%) son microfósiles y 226 (77,1%) son macrofósiles. Los microfósiles incluyen dos especies de foraminíferos (3%) y 65 de diatomeas (97%). Entre los macrofósiles, el grupo mayormente representado a nivel de clase es Mammalia con 110 especies (48,7%), seguido por Gastropoda con 37 (16,4%), Sauropsida con 35 (15,5%) y Teleostei con 30 (13,3%); las clases con menor representación son Isopoda, Scaphopoda, Amphibia y Magnoliopsida con un registro cada una. El periodo mejor representado es el Cuaternario, con 199 especies (67,9%), seguido por el Neógeno con 49 especies (16,7%) y, finalmente, el Cretácico con 45 (15,4%). Por localidad, la más rica es Chapala y Zacoalco para el Cuaternario, Tecolotlán para el Neógeno y Tamazula para el Cretácico. Las especies incluidas fueron registradas desde 1875 hasta el 2022.

Se proporciona una breve síntesis crítica en relación a estudios seleccionados de vertebrados continentales cuaternarios de Uruguay. su conocimiento se ha visto muy incrementado en diversidad del grupo dominante en el registro—los mamíferos—pero también en el de varios grupos de aves. El control temporal tiene en cuenta el esquema cronoestratigráfico propuesto para la región pampeana como herramienta de correlación bioestratigráfica y por un creciente número de edades numéricas (radiocarbono, luminiscencia ópticamente estimulada). Los sedimentos en el norte de Uruguay, Formación sopas, exhiben un rico y variado contenido fosilífero. se correlaciona con el Piso/Edad Lujanense y las edades numéricas de varios afloramientos se incluyen en el rango del Piso Marino Isotópico 3 (MIs 3). Los vertebrados sugieren diversos tipos de ambientes tales como cuerpos de agua dulce con importante desarrollo, floresta riparia, floresta semiabierta y áreas abiertas, no descartándose microambientes áridos y semiáridos. En el sur de Uruguay, se expresa la Formación Dolores, correlacionada con el Lujanense y con edades numéricas preponderantemente en el rango que incluye al Ultimo Máximo Glacial y Holoceno Temprano. Condiciones de aridez o semiaridez favorecidas por las condiciones frías del Ultimo máximo Glacial explican la presencia de algunos mamíferos que actualmente no viven en Uruguay. En barrancas costeras del Río de la Plata (sur-oeste de Uruguay), aflora la Formación Raigón, considerada de edad pliocena, pero con elementos que indican Pleistoceno Temprano y Medio (mamíferos y edades de luminiscencia ópticamente estimulada en facies terminales). Los mamíferos referidos al Pleistoceno sugieren contextos ambientales abiertos a semiabiertos tanto en base a sus adaptaciones dentarias como a estudios isotópicos. 2.11.0.0 2.11.0.0 2.11.0.0

The Rio Grande Hydrographic Basin (BRG) is located in the west of the state of Bahia, being characterized mainly by the altimetric contrast of cuestas and areas of smooth topography, in addition to being a transition area between the Cerrado and Caatinga biomes. This study aims to understand the landscape dynamics and transformation in the middle course of the BRG during the Quaternary, based on the investigation of surface covers of river terraces, inferring variations in vegetation and geomorphological processes associated with episodes of climatic pulsations. The methodology consisted of an integrated analysis involving phytoliths, granulometric analysis, and chronology through dating by Optically Stimulated Luminescence. No major changes were recorded in the vegetation cover for BRG in the Holocene, with a predominance of open vegetation with the occasional occurrence of forest remnants. However, it was possible to observe small variations that identified relatively drier periods in the Late Pleistocene and the Middle Holocene, greater humidity around 1,430 years BP, and humidity variations in the last 420 years. [ABSTRACT FROM AUTHOR]

Copyright of Cuaternario y Geomorfología is the property of Cuaternario y Geomorfologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Cuaternario y Geomorfología is the property of Cuaternario y Geomorfologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Academia Colombiana de Ciencias Exactas, Físicas y Naturales is the property of Academia Colombiana de Ciencias Exactas, Fisicas y Naturales and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de la Asociación Geológica Argentina is the property of Asociacion Geologica Argentina and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

La división del tiempo geológico más reciente está basada en eventos de carácter climático provocados por variaciones en la órbita y el eje de rotación de la Tierra a escala de miles de años. Sin embargo, la magnitud del cambio geológico causado por la humanidad a través de su joven tecnosfera está afectando negativamente a las otras esferas clásicas (atmósfera, hidrosfera, biosfera y geosfera) con su creciente demanda de materias primas y el reciclaje incompleto de sus residuos (por ejemplo, los gases de efecto invernadero) particularmente desde mediados del siglo XX. El uso masivo de combustibles fósiles para impulsar el enorme desarrollo industrial reciente ha convertido a la humanidad en el nuevo agente del cambio climático a escala planetaria. Algunas alteraciones asociadas con este nuevo régimen climático antropoceno son ya irreversibles y superan la variabilidad natural de los últimos miles de años.