Ameghiniana最新文献

{"title":"First Record of Cryptospores from the Late Ordovician–Early Silurian of Colombia: New Contribution to the Understanding of Plant Terrestrialization","authors":"C. V. Rubinstein, M. Vargas, Felipe De La Parra, V. Caballero, Julian Naranjo, N. Sánchez","doi":"10.5710/AMGH.27.07.2023.3560","DOIUrl":"https://doi.org/10.5710/AMGH.27.07.2023.3560","url":null,"abstract":"Abstract. The present study involves the palynological analysis of Late Ordovician–early Silurian samples coming from two wells drilled in the Llanos Basin of Colombia. Thirteen core samples of well A yielded a moderately preserved cryptospore assemblage comprising 17 taxa. Although composed mainly of simple forms without stratigraphic value, the marine organic-walled phytoplankton allows us to constrain the age of the palynological assemblage from the Late Ordovician (Katian–Hirnatian) to the early Silurian. A ditch-cutting sample of well B yielded marine organic-walled phytoplankton and one trilete spore species. The marine phytoplankton suggests an age no older than early Silurian for the assemblage of well B. The paleoenvironment of well A, interpreted as a braided fluvial channel system with sporadic and slight tidal influence, is supported by palynological data. The distribution of palynomorphs also suggests an increasing marine influence from the bottom to the top of the studied section. The cryptospore assemblage constitutes the first record of cryptospores of Colombia and northern South America and, therefore, the oldest evidence of land plants in this region. The presence of the trilete spore Ambitisporites avitus in strata of probably early Silurian age would represent the first record of Silurian sediments in the Llanos Basin and the oldest record of trilete spores in Colombia. Resumen. El presente estudio comprende el análisis palinológico de muestras del Ordovícico Tardío–Silúrico temprano provenientes de dos pozos de la Cuenca Llanos, en Colombia. De 13 muestras de testigo del pozo A se obtuvieron 17 taxones de criptoesporas, moderadamente preservadas. El fitoplancton marino de pared orgánica, si bien está representado en general por formas simples, sin valor estratigráfico, permite restringir la edad de la asociación palinológica del Ordovícico Tardío (Katiano–Hirnantiano) al Silúrico temprano. De una muestra de cutting del pozo B se obtuvo fitoplancton marino de pared orgánica y una espora trilete. El fitoplancton marino sugiere una edad no mayor a silúrica temprana para el pozo B. Los datos palinológicos sustentan la interpretación del paleoambiente del pozo A como un sistema de canal fluvial anastomosado, con influencia de mareas esporádica y tenue. La distribución de los palinomorfos también muestra un incremento de la influencia marina desde la base al tope de la sección estudiada. La asociación de criptoesporas constituye el primer registro de estos microfósiles en Colombia y el norte de Sudamérica y, por lo tanto, la evidencia más antigua de plantas terrestres en esta región. La presencia de la espora trilete Ambitisporites avitus en estratos de probable edad silúrica temprana, representaría el primer registro de sedimentos silúricos en la Cuenca Llanos, así como el registro más antiguo de esporas trilete en Colombia.","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"60 1","pages":"495 - 508"},"PeriodicalIF":1.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48697282","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":"Sergio Archangelsky (1931–2022)","authors":"Eduardo G. Ottone","doi":"10.5710/1851-8044-60.6.560","DOIUrl":"https://doi.org/10.5710/1851-8044-60.6.560","url":null,"abstract":"","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"126 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135208667","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":"Reassessment of Uquiasaurus heptanodonta, an Iguanian Lizard from the Late Pliocene (Uquía Formation) of Northwestern Argentina","authors":"A. Scanferla, Linda Díaz-Fernández","doi":"10.5710/AMGH.01.09.2023.3577","DOIUrl":"https://doi.org/10.5710/AMGH.01.09.2023.3577","url":null,"abstract":"Abstract. Uquiasaurus heptanodonta was originally described as an iguanian lizard from the Uquía Formation (Late Pliocene) of NW Argentina, known from numerous skull elements. Reexamination of preserved bones indicates the type series comprises more than one species belonging to the extant iguanian genus Liolaemus. The presence of a premaxilla with seven tooth positions among the bone assemblage suggests that species belonging to Liolaemus nigromaculatus group or Liolaemus montanus section have been present in this region up to the Late Pliocene (3.0 to 2.5 Ma), thus expanding the fossil record of the genus Liolaemus in the NW Argentina. Resumen. Uquiasaurus heptanodonta es un lagarto iguánido de la Formación Uquía (Plioceno Tardío) del noroeste de Argentina, conocido por numerosos elementos craneales. El reestudio de los elementos óseos conservados indica que la serie tipo comprende más de una especie perteneciente al género de lagartos iguánidos Liolaemus. La presencia de un premaxilar con siete posiciones dentarias entre el ensamble óseo sugiere que especies pertenecientes al grupo Liolaemus nigromaculatus o a la sección Liolaemus montanus han estado presentes en esta región desde el Plioceno Tardío (3,0 a 2,5 Ma), ampliando así el registro fósil del género Liolaemus en el noroeste de Argentina.","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"60 1","pages":"535 - 539"},"PeriodicalIF":1.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42471528","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":"Systematic Revision of Pre- and Post-Santacrucian Species of Protypotherium (Interatheriidae, Notoungulata)","authors":"Mercedes Fernández, J. Fernicola, E. Cerdeño","doi":"10.5710/AMGH.14.07.2023.3556","DOIUrl":"https://doi.org/10.5710/AMGH.14.07.2023.3556","url":null,"abstract":"Abstract. Within the Order Notoungulata, considered the most diverse and abundant clade of South American native ungulates, Interatheriidae (late Paleocene–Late Miocene) is one of the best-known and most derived families. Most of the interatheriids were described during the late 19th century from specimens collected from the prolific Santa Cruz Formation (Santacrucian SALMA; Burdigalian–early Langhian), Santa Cruz Province (Argentina). One of the most important interatheriids is Protypotherium due to its diversity and wide distribution in Bolivia, Chile, Uruguay, and, especially, Argentina. Protypotherium was last revised more than a century ago, with most of the species considered Typotheria incertae sedis. More recently, several species were erected within this genus by different authors. This contribution provides the taxonomic revision of the pre- and post-Santacrucian species of Protypotherium, excluding those originally erected by Florentino Ameghino. We propose P. sinclairi and P. concepcionensis as junior synonyms of P. columnifer and P. colloncurensis, respectively, and conclude that Protypotherium includes P. antiquum, P. australe, P. praerutilum, P. compressidens, P. claudum, P. columnifer, P. minutum, P. distinctum, and P. colloncurensis. Finally, we present the most complete phylogenetic analysis of Interatheriidae, at both genus and species levels. It does not recover Protypotherium as a clade due to the nesting of Caenophilus within the genus and shows that this assemblage is the sister taxon of the clade constituted by Deseadan Progaleopithecus and Archaeophylus. Resumen. Dentro del Orden Notoungulata, considerado el clado más diverso y abundante de ungulados nativos de América del Sur, Interatheriidae (Paleoceno tardío–Mioceno Tardío) es una de las familias más conocidas y derivadas. La mayoría de los interatéridos descritos a fines del siglo XIX fueron erigidos a partir de especímenes recolectados en la prolífera Formación Santa Cruz (Edad Mamífero Santacrucense; Burdigaliense–Langhiense temprano), Provincia de Santa Cruz (Argentina). Uno de los interatéridos más importantes es Protypotherium, debido a su diversidad y amplia distribución en Bolivia, Chile, Uruguay y, especialmente, Argentina. Protypotherium fue revisado por última vez hace más de un siglo y la gran mayoría de las especies fueron consideradas Typotheria incertae sedis. Más recientemente, diversos autores han erigido varias especies dentro de este género. Esta contribución presenta la revisión taxonómica de las especies de Protypotherium pre y postsantacrucenses, excluyendo aquéllas que fueron erigidas por Florentino Ameghino dentro del género. Se propone a P. sinclairi y P. concepcionensis como sinónimos junior de P. columnifer y P. colloncurensis, respectivamente, y se concluye que el género está integrado por P. antiquum, P. australe, P. praerutilum, P. compressidens, P. claudum, P. columnifer, P. minutum, P. distinctum y P. colloncurensis. Finalmente, se prese","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"60 1","pages":"540 - 559"},"PeriodicalIF":1.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44591323","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":"Late Jurassic Cassiduloids (Echinodermata, Echinoidea) from West-Central Argentina: Taxonomic and Paleogeographic Implications","authors":"Patricio Caccia, Cecilia S. Cataldo, B. Aguirre-Urreta","doi":"10.5710/AMGH.28.08.2023.3565","DOIUrl":"https://doi.org/10.5710/AMGH.28.08.2023.3565","url":null,"abstract":"Abstract. Cassiduloids are relatively well-represented in the fossil record, especially in Europe and Northern Africa, ever since their first occurrence in the Lower Jurassic. The group shows an increase in diversity and abundance at the end of the Jurassic. In Argentina, cassiduloids are represented from the Middle Jurassic upwards. This paper describes a Tithonian cassiduloid from the Picún Leufú Formation (Neuquén Basin, Argentina) identified as Mepygurus? andinus new comb. according to the poorly developed bourrelets, straight phyllodes that are continuous up to the margin, and a subpentagonal outline. The species was originally described from the Baños del Flaco Formation on the Chilean slope of the Neuquén-Aconcagua Basin. This record extends the stratigraphical range of the genus to at least the Tithonian and provides further evidence to the interpretation of the spatial continuity of shallow-water platforms during the Late Jurassic in the Andean region. Resumen. Los casiduloideos se encuentran relativamente bien representados en el registro fósil desde su aparición en el Jurásico Temprano, especialmente en Europa y norte de África. El grupo muestra un aumento en diversidad y abundancia hacia finales del Jurásico. En Argentina, se encuentran representados a partir del Jurásico Medio. En el presente trabajo se describen casiduloideos del Tithoniano de la Formación Picún Leufú (Cuenca Neuquina, Argentina) determinados como Mepygurus? andinus nueva comb. en función de sus burreletes poco desarrollados, filodes rectos y continuos hasta los márgenes, y de su ámbito subpentagonal. La especie fue originalmente descripta de la Formación Baños del Flaco, en la vertiente chilena de la Cuenca Neuquina-Aconcagüina. Este registro extiende el rango estratigráfico del género por lo menos hasta el Tithoniano y proporciona evidencia adicional para la interpretación de la continuidad espacial de las plataformas de aguas someras durante el Jurásico Tardío de la región andina.","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"60 1","pages":"522 - 534"},"PeriodicalIF":1.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49184962","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":"Trithyrodinium verrucosum (Heisecke, 1970) comb. nov., Emend: An Early Paleogene (Danian) Dinoflagellate Cyst Species from the North of Patagonia, Argentina. Regional Stratigraphic and Paleoenvironmental Relevance","authors":"M. Sol, González Estebenet, M. V. Guler","doi":"10.5710/AMGH.20.07.2023.3558","DOIUrl":"https://doi.org/10.5710/AMGH.20.07.2023.3558","url":null,"abstract":"Abstract. Trithyrodinium verrucosum comb. nov., emend. was originally described as Scriniodinium verrucosum in Danian deposits of the Roca Formation (Neuquén Basin, west Argentina) by Heisecke (1970). Well-preserved specimens recovered from the YPF.Ch.PV.es-1 borehole (Valdés Basin, east Argentina) and the re-examination of the original material allowed in this paper the emendation of the species, including recognition of an archeopyle type 3I, one of the diagnostic feature that led us to transfer the species to the genus Trithyrodinium. Based on the dinoflagellate cyst assemblages as well as the calcareous foraminifera and nannofossils content recovered from the stratigraphical interval containing Trithyrodinium verrucosum, we suggest the age of the Highest Common Occurrence (HCO) of this species not younger than middle Danian, and linked to the nannofossil Zone NP3. Hence, Trithyrodinium verrucosum may be a biostratigraphical marker for the Danian in the north of Patagonia, and the HCO is potentially useful for regional (inter-basinal) correlation of early Paleocene chronostratigraphical units from the south Atlantic basins. Also, the peak abundance of Trithyrodinium verrucosum in association with warm-water taxa (e.g., Trithyrodinium evittii) might have occurred during globally warming episodes in the Danian. Resumen. Trithyrodinium verrucosum comb. nov., emend. fue descripta originalmente como Scriniodinium verrucosum en depósitos danianos de la Formación Roca (Cuenca Neuquina, oeste de Argentina) por Heisecke (1970). Especímenes bien preservados recuperados en el Pozo YPF.Ch.PV.es-1 (Cuenca Valdés, este de Argentina) sumado al re-estudio del material original permitieron en este trabajo la enmienda de la especie, incluyendo un arqueopilo tipo 3I, uno de los rasgos diagnósticos que llevó a transferir la especie al género Trithyrodinium. Las asociaciones de quistes de dinoflagelados, foraminíferos y nanofósiles calcáreos recuperados del intervalo estratigráfico que contiene Trithyrodinium verrucosum sugiere para la ocurrencia común más alta de la especie una edad no más joven que Daniano medio, relacionada con la Zona de nanofósiles NP3. Por lo tanto, Trithyrodinium verrucosum resulta un marcador bioestratigráfico para el Daniano en el norte de Patagonia y la ocurrencia común más alta es potencialmente útil para correlacionar regionalmente (entre cuencas) unidades cronoestratigráficas del Paleoceno temprano. Además, la abundancia de Trithyrodinium verrucosum asociado con especies de aguas cálidas (e.g., Trithyrodinium evittii) podría haber ocurrido durante episodios de calentamiento global en el Daniano.","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"60 1","pages":"509 - 521"},"PeriodicalIF":1.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48935114","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":"Late Paleozoic–Early Mesozoic Insects: State of the Art on Paleoentomological Studies in Southern South America","authors":"M. B. Lara, Bárbara Cariglino, A. Zavattieri","doi":"10.5710/AMGH.03.05.2023.3545","DOIUrl":"https://doi.org/10.5710/AMGH.03.05.2023.3545","url":null,"abstract":"Abstract. A state of the art of the insects collected and described from different Permian and Triassic units in South America is given, accompanied by their brief historical record (e.g., collectors, taxonomic revision) and new high-quality photos in color. Likewise, we succinctly provide data on the paleodiversity and paleoecology of the entomological assemblages from the different units. Finally, we discuss the South American paleoentomological records in relation to equivalent deposits worldwide. The thorough, updated review of fossil insect faunas in this paper will help settling the bases for future taxonomic, diversity, and ecological studies during a time that comprised the evolutionary history of insects through two key episodes of the geological record: the end–Permian mass extinction (EPME, ∼252 Ma) and the Carnian Pluvial Event (CPE, ∼234–232 Ma). Resumen. En este trabajo presentamos información actualizada de los insectos colectados y descriptos en diferentes unidades del Pérmico y del Triásico de Sudamérica, acompañado de su breve registro histórico (v.gr., colectores, revisión taxonómica) y por nuevas fotos a color y de alta calidad. Asimismo, proporcionamos breve información sobre la paleodiversidad y paleoecología de los conjuntos de insectos fósiles en las diferentes unidades. Finalmente, discutimos el registro paleoentomológico Sudamericano y su relación con depósitos equivalentes a nivel mundial. La revisión exhaustiva y actualizada de los insectos fósiles que brinda este documento podrá ser utilizado como base para futuros trabajos taxonómicos, de diversidad y ecológicos durante un tiempo en la historia evolutiva de los insectos que comprendió dos episodios claves en el registro geológico: la extinción masiva de finales del Pérmico (∼252 Ma) y el Evento Pluvial del Carniano (∼234–232 Ma).","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"60 1","pages":"418 - 449"},"PeriodicalIF":1.0,"publicationDate":"2023-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45341399","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":"Review of “Cuando Las Primaveras Comenzaron a Tener Flores”","authors":"M. Gandolfo","doi":"10.5710/1851-8044-60.5.492","DOIUrl":"https://doi.org/10.5710/1851-8044-60.5.492","url":null,"abstract":"","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"60 1","pages":"492 - 493"},"PeriodicalIF":1.0,"publicationDate":"2023-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47383051","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":"Middle Triassic Continental Palynological Assemblages of San Rafael Depocenter, Central-Western Argentina","authors":"P. Gutiérrez, A. Zavattieri","doi":"10.5710/AMGH.31.03.2023.3549","DOIUrl":"https://doi.org/10.5710/AMGH.31.03.2023.3549","url":null,"abstract":"Abstract. This contribution presents a comprehensive study of the unique and rich terrestrial Middle Triassic palynoflora recovered from the Quebrada de los Fósiles Formation, lower unit of the Puesto Viejo Group, San Rafael Depocenter, Mendoza Province, Argentina. The palynoflora was recorded at two sections of the unit (Quebrada de los Fósiles creek and Río Seco de la Quebrada creek), yielding diverse and well-preserved spores, pollen, freshwater algae, and fungal associations. Herein, 259 spore-pollen species are described and/or illustrated, from which eight are new: Baculatisporites magnus sp. nov., Carnisporites microspinous sp. nov., Leschikisporis variabilis sp. nov., Neoraistrickia stricta sp. nov., Limatulasporites rugulatus sp. nov., Aratrisporites circularis sp. nov., Protohaploxypinus bonapartei sp. nov. and P. diazii sp. nov. The following new combinations are proposed: Brevitriletes decorus comb. nov., B. pamelae comb. nov., B. sandrae comb. nov., Cuneatisporites cacheutensis comb. nov., C. salujhai comb. nov., and Pityosporites thoracatus comb. nov.. A new emendation for Alisporites cymbatus is instituted, and A. libyaensis nom. nov. is a new name to replace A. plicatus. These microfloras present varied parental vegetation, containing high proportions of spores from Pleuromeiales, Equisetales, Marattiales, and Corystospermales pollen. The grains of Araucariaceae, Cupressaceae, Voltziales, Cordaitales, Gnetales, and Ginkgoales/Cycadales are recorded in smaller proportions. Zygospores of chlorophytic algae and fungi are also recorded in these assemblages. The microflora of the Quebrada de los Fósiles Formation is distinctive, quantitatively and qualitatively, from the rest of the Triassic microfloras, exhibiting the highest similarities in its composition with the associations of the La Veteada (Early Triassic, Olenekian) and Cerro de Las Cabras (Late Anisian–Early Ladinian) formations. Resumen. En esta contribución se presenta un estudio exhaustivo de las únicas y ricas palinofloras terrestres del Triásico Medio recuperadas de la Formación Quebrada de los Fósiles, unidad inferior del Grupo Puesto Viejo, Depocentro San Rafael, provincia de Mendoza, Argentina. Las palinofloras se registraron de dos secciones (Quebrada de los Fósiles y Río Seco de la Quebrada), e incluyen esporas, polen, algas de agua dulce y asociaciones fúngicas diversas y bien conservadas. En este trabajo, se describen y/o ilustran 259 especies de polen y esporas de las cuales 8 son nuevas: Baculatisporites magnus sp. nov., Carnisporitas microspinous sp. nov., Leschikisporis variabilis sp. nov., Neoraistrickia stricta sp. nov., Limatulasporites rugulatus sp. nov., Aratrisporites circularis sp. nov., Protohaploxypinus bonapartei sp. nov. y P. diazii sp. nov. Se proponen las combinaciones: Brevitriletes decorus comb. nov., B. pamelae comb. nov., B. sandrae comb. nov., Cuneatisporites cacheutensis comb. nov., C. salujhai comb. nov. y Pityosporites thoracatus comb. nov","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"60 1","pages":"391 - 417"},"PeriodicalIF":1.0,"publicationDate":"2023-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49452842","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":"Taphonomic Signature of Glycymeris longior Shells (Bivalvia) and its Potential as Paleoenvironmental Proxy for the Quaternary of Northern Patagonia (Argentina)","authors":"Sol Bayer, J. Nóbile, D. Muñoz, E. Morsan, Gisela A. Morán, E. Fucks, Sandra Gordillo","doi":"10.5710/AMGH.10.07.2023.3552","DOIUrl":"https://doi.org/10.5710/AMGH.10.07.2023.3552","url":null,"abstract":"Abstract. 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. Resumen. Una de las especies de bivalvos más abundantes que habita en la playas y depósitos cuaternarios del Golfo San Matías (Patagonia argentina, Océano Atlántico sudoccidental) es Glycymeris longior. Su gran abundancia y amplia distribución geográfica, hacen que G. longior sea una especie objetivo para estudios tafonómicos. Por lo cual, describimos el perfil tafonómico que registran sus valvas en la Bahía San Antonio (Golfo San Matías, Argentina) con el objetivo de contribuir a futuras comparaciones tafonómicas, con material de playas actuales o de depósitos cuaternarios donde esta especie se encuentre. Las valvas de G. longior de los depósitos holocenos de Punta Delgado mostraron dos patrones de preservación diferentes caracterizados por diferencias en la intensidad de fragmentación, redondeamiento y cementación de sus valvas. Las valvas de PD2018A y PD2018B estuvieron sometidas a un flujo de agua continuo y poco intenso. Éstas permanecieron en la interfase sedimento-agua con menor intensidad hidrodinámica, lo que favorecería una alta cementación. Por otro lado, las valvas de PD2016 estuvieron sujetas también","PeriodicalId":50819,"journal":{"name":"Ameghiniana","volume":"61 22","pages":"450 - 464"},"PeriodicalIF":1.0,"publicationDate":"2023-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41243912","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}