Ameghiniana最新文献

{"title":"Paleopathologies of the Clavicles of the Giant Ground Sloth Megatherium americanum (Mammalia, Xenarthra) from the Pleistocene of the Pampean Region (Argentina)","authors":"K. Chichkoyan, C. Villa, Viola Winkler, L. Manuelli, Gabriel E. Acuña Suárez","doi":"10.5710/AMGH.15.10.2022.3509","DOIUrl":"https://doi.org/10.5710/AMGH.15.10.2022.3509","url":null,"abstract":"Abstract. This study presents pathological conditions observed in the clavicular joints of the extinct giant ground sloth Megatherium americanum. Clavicles are key for shoulders and forelimbs movements in both feeding and locomotion, two aspects largely discussed in this species. Consequently, paleopathologies of this bone are a direct proxy for understanding paleoecological issues and provide indirect evidence of the paleoenvironment of this species. Eleven clavicles of Megatherium americanum from the Pleistocene of the Pampean region (Argentina), housed in European museums, have been studied. We analyzed the external and inner structure of the bone through macroscopic observation and imaging techniques (e.g., Computed tomography scanner [CT] and 3D surface scanner) and uncovered subchondral sclerosis, exostosis, cysts, and draining sinuses in seven of the analyzed samples. Our results indicate that the clavicles showed signs of arthritis and infections and were subjected to trauma. Adduction/abduction and superior movements when standing next to trees for feeding, and compressive forces due to quadrupedal locomotion by this species, might have affected the clavicle joints. This suggests that the animals tried to reach the higher levels of arbors, and indirectly implies the presence of edible groves into the grassland Pampean landscape. Based on the paleopathologies of the clavicle, the paleoecological aspects are in line with other ecological studies performed on this species. Resumen. Este estudio presenta condiciones patológicas observadas en las articulaciones claviculares del perezoso terrestre extinto Megatherium americanum. Las clavículas son clave para los movimientos de los hombros y miembros anteriores tanto en la alimentación como en la locomoción, dos aspectos ampliamente discutidos en esta especie. En consecuencia, las paleopatologías de este hueso son un proxy directo para entender aspectos paleoecológicos y proporcionar información indirecta sobre el paleoambiente de dicha especie. Se han revisado once clavículas de Megatherium americanum del Pleistoceno de la región pampeana (Argentina) alojadas en museos europeos. Analizamos la estructura exterior e interior de estos huesos a través de observación macroscópica y técnicas de imagen (por ejemplo, escáner de tomografía computarizada [TC] y escáner de superficie 3D) y descubrimos esclerosis subcondrales, exostosis, quistes y cavidades o conductos de drenaje en siete muestras. Los resultados indican que las clavículas mostraron signos de artritis e infecciones y fueron sometidas a traumatismos. Esta especie usualmente realizaba movimientos de aducción/abducción y superior al estar cerca de los árboles para alimentarse, y movimientos de compresión debido a la locomoción cuadrúpeda, lo que probablemente afectaba las articulaciones de la clavícula. Esto sugiere que los animales intentaron alcanzar el dosel arbóreo, e, indirectamente, la presencia de arboledas comestibles en el paisaje d","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"59 1","pages":"390 - 406"},"PeriodicalIF":1.0,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42256766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Seal (Carnivora, Phocidae) Record from the Late Miocene–Pliocene of Guafo Island, Southern Chile","authors":"Ana M. Valenzuela-Toro, N. Pyenson","doi":"10.5710/AMGH.06.07.2022.3498","DOIUrl":"https://doi.org/10.5710/AMGH.06.07.2022.3498","url":null,"abstract":"Abstract. Several remains of fossil phocids (i.e., true seals) have been consistently reported from the Late Miocene and Pliocene strata from the southwestern coast of South America. These fossils, along with those from fossil otariids (fur seals and sea lions), indicate that a widespread turnover from a phocid- to an otariid-dominated fauna in the Southern Hemisphere transpired during the Late Pliocene or Early Pleistocene. The Neogene fossil record of phocids is primarily dominated by occurrences from southern Peru and northern Chile, with a few isolated findings from central Chile. Until now, no records of fossil seals have been documented from southern Chile, constraining our understanding of the latitudinal variability of the pinniped assemblages and the mechanisms by which their faunal turnover occurred. Here we report the fossil remains of a fossil seal (Monachinae indet.) from the Late Miocene–Pliocene sediments of Guafo Island in the south of Chile. These remains constitute the southernmost occurrence of a fossil seal from the South Pacific Ocean, expanding their geographic range in the southeastern coast of South America more than 1000 km. This finding reveals that phocids inhabited temperate and subantarctic regions in Chilean Patagonia during the late Neogene, suggesting a broader environmental tolerance than previously recognized. Resumen. Diversos restos de fócidos fósiles (focas) han sido consistentemente reportados en niveles del Mioceno Tardío y Plioceno de América del Sur. Estos fósiles, junto a aquellos de otáridos fósiles (lobos marinos), indican que durante el Plioceno Tardío o Pleistoceno Temprano se produjo un recambio generalizado desde una fauna dominada por fócidos a una dominada por otáridos en el Hemisferio Sur. El registro fósil de fócidos del Neógeno está dominado principalmente por ocurrencias en el sur de Perú y el norte de Chile, con algunos hallazgos aislados en el centro de Chile. Hasta ahora, no se han reportado focas fósiles en el sur de Chile, limitando nuestra comprensión de la variabilidad latitudinal de los ensambles de pinnípedos, así como de los mecanismos por los cuales ocurrió su recambio faunístico. Aquí describimos los restos fósiles de una foca fósil (Monachinae indet.) de los sedimentos del Mioceno Tardío-Plioceno de la Isla Guafo en el sur de Chile. Estos restos constituyen la ocurrencia más austral de una foca fósil en el Océano Pacífico Sur, ampliando su rango de distribución geográfica en la costa sureste de América del Sur en más de 1000 km. Este hallazgo revela que los fócidos habitaron regiones templadas y subantárticas a lo largo de la Patagonia Chilena durante el Neógeno tardío, lo que sugiere una tolerancia ambiental más amplia que la reconocida anteriormente para este grupo.","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"59 1","pages":"355 - 365"},"PeriodicalIF":1.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43932075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nora M. Sabattini (1941-2021)","authors":"A. Riccardi","doi":"10.5710/1851-8044-59.5.366","DOIUrl":"https://doi.org/10.5710/1851-8044-59.5.366","url":null,"abstract":"","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"59 1","pages":"366 - 369"},"PeriodicalIF":1.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44136403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A New Species of Baurubatrachus (Anura, Neobatrachia) from the Late Cretaceous Adamantina Formation of Brazil Furnishes Evidence on the Diversity of this Bizarre Genus","authors":"P. Muzzopappa, F. Iori, Fellipe P. Muniz, A. Martinelli","doi":"10.5710/AMGH.29.07.2022.3505","DOIUrl":"https://doi.org/10.5710/AMGH.29.07.2022.3505","url":null,"abstract":"Abstract. In the present paper, we report new anuran remains recovered from strata referred to the Adamantina Formation (Upper Cretaceous) cropping out near Catanduva city, São Paulo, Brazil. The remains represent two individuals, one of which bears a set of peculiar characteristics, both cranial and postcranial, that allows us to assign them to the already known genus Baurubatrachus. To date, the genus was only represented by the holotype of Baurubatrachus pricei, recovered from the Upper Cretaceous Serra da Galga Formation (which is younger than the Adamantina Formation), near Peirópolis (Minas Gerais, Brazil), 200 km north of Catanduva City. The lesser ossification as well as the slender configuration of the scapula and ilia of the new remains, relative to B. pricei, points to the identification of a new species, Baurubatrachus santosdoroi sp. nov. The detailed study of the peculiar anatomy of these specimens provides new osteological features for the genus, such as the presence of a subtympanic foramen, as well as new character states for other traits to be considered in future systematic studies. Resumen. El presente trabajo reporta nuevos restos de anuros hallados en estratos referidos a la Formación Adamantina (Cretácico Superior) aflorantes en las proximidades de la ciudad de Catanduva, San Pablo, Brasil. Los restos representan dos individuos, uno de ellos portador de una cantidad de características particulares, cranianas y postcranianas que permite asignarlo al género ya conocido Baurubatrachus. Hasta la fecha, el género estaba únicamente representado por el holotipo de Baurubatrachus pricei, recuperado de la Formación Serra da Galga del Cretácico Superior (que es más joven que la Formación Adamantina), cerca de la ciudad de Peirópolis (Minas Gerais, Brasil), 200 km al norte de la ciudad de Catanduva. La menor osificación, así como la condición más esbelta de las cinturas pectoral y pélvica de estos restos respecto de B. pricei, indica la presencia de una especie diferente, Baurubatrachus santosdoroi sp. nov. El estudio detallado de la anatomía particular de estos especímenes permitió identificar nuevos caracteres como la presencia de un foramen subtimpánico y, a su vez, nuevos estados de carácter para otras características, las cuales son plausibles de ser utilizadas en futuros estudios sistemáticos.","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"59 1","pages":"297 - 316"},"PeriodicalIF":1.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43700118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A New Nanoid Titanosaur (Dinosauria: Sauropoda) from the Upper Cretaceous of Brazil","authors":"B. Navarro, A. Ghilardi, T. Aureliano, V. Díaz, K. Bandeira, André Cattaruzzi, F. Iori, A. Martine, A. Carvalho, L. Anelli, M. Fernandes, H. Zaher","doi":"10.5710/AMGH.25.08.2022.3477","DOIUrl":"https://doi.org/10.5710/AMGH.25.08.2022.3477","url":null,"abstract":"Abstract. Titanosaurian sauropods are known to exhibit remarkable body size disparity, with some taxa famed for nearing the zenith of terrestrial vertebrate body size. Here, we describe a new titanosaurian – Ibirania parva gen. et sp. nov. – from the Upper Cretaceous (Santonian–Campanian) São José do Rio Preto Formation of Bauru Basin, in which represents one of the smallest sauropods known to date. The new taxon is diagnosed by seven autapomorphies and had an estimated body length of 5.7 m. Histological and µCT scan analyses showed that this new taxon is represented by skeletally mature individuals, which had attained somatic maturity prior to death. Phylogenetic analyses recovered the new taxon deeply nested within Saltasaurinae, a clade previously known by small-sized forms. Ibirania parva gen. et sp. nov. brings new information indicating that the body size reduction in some titanosaurians could be driven by recurrent ecophysiographical settings, present in South America prior to the diversity peak attained by the group during the Campanian–Maastrichtian. Resumen. Los saurópodos titanosaurios son conocidos por mostrar una notable disparidad de tamaño corporal, con algunos taxones famosos por acercarse al cenit del tamaño corporal de un vertebrado terrestre. En este trabajo se describe un nuevo titanosaurio – Ibirania parva gen. et sp. nov. – del Cretácico Superior (Santoniano–Campaniano) de la Formación São José do Rio Preto de la Cuenca Bauru, el cual representa uno de los saurópodos más pequeños conocidos hasta la fecha. El nuevo taxón se puede diagnosticar gracias a siete autapomorfías y tenía una longitud corporal estimada de 5.7 m. Los análisis histológicos y de microtomografía computarizada muestran que este nuevo taxón está representado por individuos esqueléticamente maduros, que habrían alcanzado la madurez somática antes de la muerte. Los análisis filogenéticos han recuperado la inclusión del nuevo taxón dentro de Saltasaurinae, un clado previamente conocido por formas de pequeño tamaño. Ibirania parva gen. et sp. nov. arroja nueva información indicando que la disminución del tamaño corporal en algunos titanosaurios podría estar impulsado por escenarios ecofisiográficos recurrentes, presentes en América del Sur antes del pico de diversidad alcanzado por el grupo durante el Campaniano–Maastrichtiano.","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"59 1","pages":"317 - 354"},"PeriodicalIF":1.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42517779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mississippian Palynoflora from the Clarke River Basin, North Queensland, Australia","authors":"G. Playford","doi":"10.5710/AMGH.15.06.2022.3504","DOIUrl":"https://doi.org/10.5710/AMGH.15.06.2022.3504","url":null,"abstract":"Abstract. The diverse, well-preserved spore assemblage hosted by the non-marine Lyall Formation of the Clarke River Basin in north Queensland includes many species reported previously from Mississippian strata elsewhere in Australia, together with one new genus and species (Apricasporites cancellosus) and seven additional new species (Granulatisporites commutabilis, Anapiculatisporites radiatus, Camptotriletes inaequabilis, C. suggrandis, Convolutispora inreligata, Foveosporites magnus, and Endosporites circumsaeptus). In terms of the existing palynostratigrahic zonation of Australian Mississippian successions, the palynoflora is clearly attributable to the Visean Anapiculatisporites largus Zone, first recognized in the Bonaparte Basin (northwestern Australia) and well-represented also in the Drummond Basin, east-central Queensland. However, a few constituent species are known as components of the succeeding Grandispora maculosa Zone (mid/late Visean–early Serpukhovian). This study provides confirmation of floristic affinities between Eastern and Western Gondwana during the Mississippian. Resumen. El conjunto diverso y bien conservado de esporas registrado en la Formación Lyall de la cuenca del río Clarke, en el norte de Queensland, incluye muchas especies del Mississippiano reportadas previamente en otras partes de Australia, a la vez que incluye un nuevo género y especie (Apricasporites cancellosus) y siete nuevas especies adicionales (Granulatisporites commutabilis, Anapiculatisporites radiatus, Camptotriletes inaequabilis, C. suggrandis, Convolutispora inreligata, Foveosporites magnus y Endosporites circumsaeptus). En términos de la zonación palinoestratigráfica existente de las sucesiones mississippianas de Australia, la palinoflora es claramente atribuible a la zona Anapiculatisporites largus del Viseano, reconocida por primera vez en la cuenca de Bonaparte (noroeste de Australia) y bien representada también en la cuenca de Drummond, en el centro-este de Queensland. Sin embargo, algunas especies constituyentes se conocen como componentes de la sucesiva Zona Grandispora maculosa (Viseano medio/final–Serpukhoviano temprano). Este estudio confirma las afinidades florísticas entre el este y el oeste de Gondwana durante el Mississippiano.","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"59 1","pages":"225 - 264"},"PeriodicalIF":1.0,"publicationDate":"2022-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47353099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sclerobiosis: A Term for Colonization of Marine Hard Substrates","authors":"M. V. Romero, S. Casadío, Claudia Bremec, D. Giberto","doi":"10.5710/AMGH.21.06.2022.3486","DOIUrl":"https://doi.org/10.5710/AMGH.21.06.2022.3486","url":null,"abstract":"Abstract. Ancient and modern marine environments are usually characterized by colonizers associated with living and dead organisms, as well as inorganic substrates. There are different terminologies to characterize these colonizations, i.e., if the roots of the terms refer to the colonizer or the colonized substrate. The terminology stated by Paul D. Taylor and Mark A. Wilson is considered here as background to characterize marine ancient and modern assemblages on hard substrates. These authors define the term “sclerobiont”, but not “sclerobiosis”. We focus on the term “sclerobiont” and the need for a formal term, “sclerobiosis”. There is no definition of the latter, which is beginning to be used as a synonym for “epibiosis”. Here we define “sclerobiosis” as the spatial association between any kind of hard substrate and a diversity of life forms, which can occupy different spatial location of the hard substrate. With regard to colonization of marine hard substrates, “epibiosis” is included within “sclerobiosis”. The goal is to clarify in which cases the use of each term is more appropriate, according to the criteria considered in the cited definitions of the terms. When studying different aspects of the colonization of living, dead and inorganic hard substrates, and even when we want to establish comparisons of colonizations over time and space, it is useful to have a term that encompasses all these associations between substrates and colonizers. “Sclerobiosis” is proposed to aid a uniform language among deep-time and modern ecology researchers, especially those working on both settings. Resumen. La colonización de organismos vivos y muertos, así como también de sustratos inorgánicos, es un proceso común en ambientes marinos fósiles y actuales. Existen diferentes terminologías para caracterizar estas colonizaciones, esto es, si las raíces de los términos se refieren al colonizador o al sustrato colonizado. En este trabajo se considera la terminología de Paul D. Taylor y Mark A. Wilson para caracterizar los ensambles marinos fósiles y actuales sobre sustratos duros. Estos autores definen el término “esclerobionte”, pero no “esclerobiosis”. Por ello, nos centramos en el término “esclerobionte” y en la necesidad de un término formal, “esclerobiosis”. No existe una definición original para este último, el cual se está comenzando a utilizar como sinónimo de “epibiosis”. “Esclerobiosis” es la asociación espacial entre cualquier tipo de sustrato duro y una diversidad de formas de vida que puede ocupar diferentes ubicaciones espaciales del sustrato. Considerando la colonización de sustratos duros marinos, “epibiosis” queda incluida dentro de “esclerobiosis”. El objetivo es aclarar en qué casos el uso de cada término es más apropiado de acuerdo con los criterios considerados en las definiciones citadas. A la hora de estudiar diferentes aspectos de la colonización de sustratos duros vivos, muertos e inorgánicos, e incluso cuando queremos establecer compara","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"59 1","pages":"265 - 273"},"PeriodicalIF":1.0,"publicationDate":"2022-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49505587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrating Fossil Diagenesis and Geochemistry in the Paleoenvironmental Reconstruction of a Tank Deposit Bearing Quaternary Vertebrates in Northeastern Brazil","authors":"Juliana Carvalho-Laurentino, K. Porpino, H. I. Araújo-Júnior","doi":"10.5710/AMGH.16.05.2022.3459","DOIUrl":"https://doi.org/10.5710/AMGH.16.05.2022.3459","url":null,"abstract":"Abstract. In this work, we studied the fossil diagenesis of vertebrates recovered from a quaternary tank deposit at Taperoá, Paraíba State, northeastern Brazil. The samples were classified based on the staining pattern and examined using petrography, fluorescence (XRF), and X-ray diffraction (XRD) analyses. A principal component analysis (PCA) was used to verify the relationship between the staining and chemical composition of the fossils. Microfractures, microcrackins, permineralization, and replacement were observed, although the bone microstructure was well preserved. The XRF analysis showed that the specimens with the highest percentage of manganese and iron appeared darkest (black and red shades, respectively), which the PCA confirmed. The variation in rare earth elements (REE) values indicates the occurrence of temporal mixing. The XRD analysis showed a predominance of hydroxyapatite; therefore, fossils may preserve the original mineral composition. Root marks and sun exposure bleaching were also observed, which suggested reworking and temporal mixing. Thus, we conclude that the tank deposit of Taperoá underwent different environmental conditions, from oxidising to reducing and wet to dry conditions, which caused diagenetic differences and represent a typical setting for tank deposits. This confirms the seasonality of the semi-arid climate of the Brazilian Intertropical Region (RIB) during the Pleistocene epoch. Resumen. En este trabajo estudiamos la fosildiagénesis de vertebrados recuperados de un depósito cuaternario en Taperoá, Estado de Paraíba, noreste de Brasil. Las muestras se clasificaron basado en el patrón de colour y se examinaron mediante descripción petrográfica, análisis de fluorescencia (FRX) y difracción de rayos X (XRD), con análisis de componentes principales (PCA) utilizado para verificar la relación entre la coloración y la composición química de los fósiles. Se observaron microfracturas, microroturas, permineralización y substituición, pero la microestructura ósea está bien conservada. El análisis FRX mostró que las especies con el mayor porcentaje de manganeso y hierro aparecen más oscuras (tonos de negro y rojo respectivamente); esto fue confirmado por análisis de PCA. Los valores variables de los Elementos de Tierras Raras (ETR) indican la ocurrencia de una mezcla temporal. El análisis XRD mostró un predominio de hidroxiapatita, por lo que es posible considerar que los fósiles conservaron la composición mineral original. También se observaron marcas de raíces y decoloración por exposición al sol, lo que sugiere retrabajo y mezcla temporal. Así, concluimos que el depósito tanque de Taperoá pasó por diferentes condiciones ambientales, desde redox y húmedo a seco, provocando diferencias diagenéticas - configuración típica en depósitos tanque. Esto confirma la estacionalidad del clima semiárido de la Región Intertropical Brasileña (RIB) durante la época del Pleistoceno.","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"59 1","pages":"274 - 296"},"PeriodicalIF":1.0,"publicationDate":"2022-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44605717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fossil Bryophytes from the Middle Triassic Sorocayense Group, San Juan Province, Central-Western Argentina","authors":"Adolfina Savoretti, J. Bodnar, Eliana P. Coturel, Marisol Beltrán","doi":"10.5710/AMGH.26.02.2022.3469","DOIUrl":"https://doi.org/10.5710/AMGH.26.02.2022.3469","url":null,"abstract":"Abstract. We describe fossil liverworts, mosses, and thallose forms of unknown affinity from the Barreal and Cortaderita formations (Sorocayense Group, Middle Triassic) in the Barreal depocenter, southwestern San Juan Province. The specimens are impressions-compressions of gametophytes and sporophytes, preserved in claystones, siltstones, and tuffaceous and bentonitic silty sandstones. The thallose forms consist of dichotomous simple thalli lacking evidence of a midrib and are assigned to the genus Thallites. Within the liverworts, we identified a new genus and two new species. Ricciellites unsaltoensis gen. et sp. nov. is characterized by thalli forming partial rosettes with distinct midrib, polygonal cells, air pores surrounded by a ring of cells, enclosed sporophytes, and ventral scales arranged in two rows. Ricciopsis cortaderitaensis sp. nov. has thalli forming rosettes, with distinct midrib, polygonal cells, and rhizoids. We also describe two types of acrocarpous mosses assignable to the genus Muscites. They are characterized by delicate unbranched axes with lanceolate unicostate leaves. Muscites sp. 1 is represented by several specimens arranged in a loose cushion, while Muscites sp. 2 corresponds to isolated specimens. Together, these fossils represent the first unequivocal evidence of mosses and liverworts for the Middle Triassic of Argentina. Given the scarcity of bryophyte megafossils of Triassic age worldwide (31 worldwide, three confirmed records for Argentina), these findings add significantly to the bryophyte fossil record. Resumen. En este trabajo se describen fósiles de hepáticas, musgos y formas talosas de afinidad desconocida provenientes de las formaciones Barreal y Cortaderita, Grupo Sorocayense, Triásico Medio, aflorantes en el depocentro de Barreal, sudoeste de la provincia de San Juan. Los ejemplares corresponden a impresiones-compresiones de gametofitos y esporofitos, preservadas en niveles de arcilitas, limolitas y areniscas limosas tobáceas y bentoníticas. Las formas talosas corresponden a talos dicotómicos simples sin evidencia de línea media asignados al género Thallites. Entre las hepáticas, se identificaron un nuevo género y dos nuevas especies. Ricciellites unsaltoensis gen. et sp. nov se caracteriza por un talo que forma rosetas parciales, con línea media marcada, células poligonales, poros aeríferos rodeados por un anillo de células, esporofitos inmersos en el gametofito y escamas ventrales dispuestas en dos hileras. Ricciopsis cortaderitaensis sp. nov. presenta talos en roseta, con línea media marcada, células poligonales y rizoides. En cuanto a los musgos, se reconocieron dos formas asignables a Muscites. Se caracterizan por presentar ejes delicados, no ramificados, con hojas lanceoladas y costa simple. Muscites sp. 1 está representada por varios especímenes dispuestos en un cojín laxo, mientras que Muscites sp. 2 corresponde a ejemplares aislados. Los fósiles estudiados representan la primera evidencia inequív","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"59 1","pages":"179 - 200"},"PeriodicalIF":1.0,"publicationDate":"2022-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48164877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Taxonomic Status of Notocaiman stromeri (Crocodylia, Alligatoroidea) and the Early Diversity of South American Caimanines","authors":"Paula Bona, F. Barrios, M. Ezcurra, M. V. Fernandez Blanco","doi":"10.5710/AMGH.27.02.2022.3470","DOIUrl":"https://doi.org/10.5710/AMGH.27.02.2022.3470","url":null,"abstract":"Abstract. The early diversification of caimanines is one of the least understood aspects of the evolutionary history of Crocodylia. The Palaeogene Argentinian caimanine record is extremely relevant because it provides key information on the early history of the clade. Most of the Palaeocene South American species are only or mainly known from partial lower jaws. Among the oldest Argentinian caimanines, Notocaiman stromeri (middle Palaeocene, Las Violetas Formation, Chubut Province) and Eocaiman palaeocenicus (lower Palaeocene, Salamanca Formation, Chubut Province) are represented by a partial left dentary and a fairly complete lower jaw, respectively. Notocaiman stromeri, has been phylogenetically interpreted from an alligatorid closely related to Eocaiman to an indeterminate eusuchian, but a modern anatomical revision of this species is lacking. Here, we redescribe in detail the only known specimen of Notocaiman stromeri (PVL 752) to revise its taxonomy and phylogenetic relationships. We concluded that Notocaiman and Notocaiman stromeri are nomina dubia and we refer PVL 752 to Eocaiman cf. E. palaeocenicus. Our phylogenetic analysis found Eocaiman palaeocenicus as the sister taxon to the Eocaiman cavernensis + Eocaiman itaboraiensis clade. Thus, here we reduce the alpha taxonomic diversity of alligatorids in the Palaeogene of South America but reinforce a geographically broad diversification of the genus Eocaiman, from the Palaeocene to the Eocene/Miocene in this continent. Resumen. La diversificación temprana de los caimaninos es uno de los aspectos menos comprendidos de la historia evolutiva de Crocodylia. El registro de caimaninos del Paleógeno de Argentina es extremadamente relevante porque proporciona información clave sobre la historia temprana de este clado. La mayoría de las especies sudamericanas del Paleoceno se conocen principalmente a partir de mandíbulas inferiores parciales. Entre los caimaninos argentinos más antiguos se encuentran Notocaiman stromeri (Paleoceno medio, Formación Las Violetas, Provincia del Chubut) y Eocaiman palaeocenicus (Paleoceno inferior, Formación Salamanca, Provincia del Chubut), cuyos holotipos están representados por un dentario izquierdo parcial y una mandíbula inferior bastante completa, respectivamente. Notocaiman stromeri, se ha interpretado filogenéticamente desde un alligatórido estrechamente relacionado con Eocaiman a un eusuquio indeterminado, pero aún falta una revisión anatómica actualizada de esta especie. Aquí, redescribimos en detalle el único espécimen conocido de Notocaiman stromeri (PVL 752) con el objetivo de revisar su taxonomía y relaciones filogenéticas. Concluimos que Notocaiman y Notocaiman stromeri son nomina dubia y referimos PVL 752 a Eocaiman cf. E. palaeocenicus. Nuestro análisis filogenético encontró a Eocaiman palaeocenicus como el taxón hermano del clado Eocaiman cavernensis + Eocaiman itaboraiensis. Entonces, aquí reducimos la diversidad taxonómica alfa de los alligatóridos p","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"59 1","pages":"210 - 220"},"PeriodicalIF":1.0,"publicationDate":"2022-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42749361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}