Comunidades de moluscos difieren entre microambientes en un lago somero de la región pampeana, Argentina

The aim of this study is to compare the faunistic mollusk composition at a local scale, in different sites within a shallow lake, and to evaluate the relation between abundance and richness of mollusks and the environmental variables. The distribution of the mollusks within the water body was patchy but not random. Three of the sites were deeper, mainly dominated by emergent macrophytes and were characterized by the dominance of the gastropods Heleobia parchappii, Physa acuta and Uncancylus concentricus. In contrast, the other two sites were dominated by Biomphalaria peregrina and the bivalve Musculium argentinum, and were characterized by lower depth and pH, and higher vegetation diversity and water temperature. This study evidences the patchiness of freshwater mollusk species in a Pampean shallow lake, where environmental factors partially explain the local distribution within the lake.El objetivo de este trabajo es comparar la distribución de los ensambles de moluscos en diferentes sitios dentro de un lago somero pampeano y evaluar la relación que existe entre la abundancia y la riqueza de moluscos y las variables ambientales. Los moluscos mostraron una distribución en parches, pero no azarosa. Tres de los sitios que eran más profundos y que estaban dominados por macróftas emergentes estuvieron caracterizados por mayores abundancias de los gasterópodos Heleobia parchappii, Physa acuta y Uncancylus concentricus. En contraste, los otros dos sitios que estuvieron caracterizados por menores profundidades, menores pH, mayor diversidad de vegetación y temperaturas del agua más altas estuvieron dominados por Biomphalaria peregrina y por el bivalvo Musculium argentinum. Este estudio evidencia la distribución en parches de moluscos dulceacuícolas en lagos someros de la ecorregión pampeana donde las variables ambientales explican de forma parcial la distribución local dentro del lago.Fil: Tietze, Eleonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Cristini, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Grondona, Sebastian. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Geología de Costas y del Cuaternario. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto de Geología de Costas y del Cuaternario; Argentin

Medición experimental de la resistencia mecánica de ensambles vivos y muertos de Amiantis purpurata y su interpretación tafonómica

El objetivo del presente trabajo es evaluar en forma comparativa la resistencia mecánica deespecímenes procedentes de ensambles vivos y ensambles de muerte de la almeja púrpuraAmiantis purpurata y su implicancia en la preservación. Esta especie es frecuente en el registrofósil y sus valvas son habitualmente encontradas en gran abundancia en los ensambles demuerte de las playas de la costa bonaerense junto a otras especies como Glycimeris longior yBrachidontes rodriguezii. Estos ensambles representan una acumulación de varias generacionesy están sometidos a procesos tafonómicos tanto físico-químicos (acción del oleaje, corrientes ytormentas, disolución, fragmentación) como biológicos (biodegradación) que ocurren en la zonatafonómicamente activa del ambiente costero. Se espera que las valvas de los ensambles demuerte presenten menor resistencia mecánica como producto del tiempo de exposición a losagentes tafonómicos. Para llevar adelante el objetivo se analizaron 200 valvas (100 VD y 100 VI)muestreadas de un ensamble de vida en las playas de Mar Chiquita provenientes de un arribazónde marea, y 378 valvas (178 VD y 200 VI) muestreadas de ensambles de muerte en la línea demarea alta de las playas de Mar Chiquita y Santa Clara. Se separaron las valvas en izquierda yderecha y se tomaron las medidas morfológicas (largo, alto, ancho y espesor de la valva) con uncalibre digital y se pesaron usando una balanza digital. Se cuantificó el contenido de materiaorgánica de la valva y su mineralogía por difracción de rayos X. Por último se realizaron ensayosmecánicos de compresión con equipo Instron Emic 23-50 para estimar la resistencia mecánicade las valvas. Los resultados preliminares mostraron una correlación positiva entre el peso y laresistencia mecánica en ambas valvas y que no hubo diferencia significativa en la resistenciamecánica entre las valvas derecha e izquierda. Los defectos encontrados en las valvas o lasposibles marcas de depredación no tuvieron efecto significativo en la resistencia mecánica.Fil: Cristini, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Ballarre, Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaXI Jornadas Nacionales de Ciencias del Mar y XIX Coloquio de OceanografíaArgentinaUniversidad Nacional de la Patagonia San Juan Bosc

Molluscan taphonomic patterns below the sediment-water interface in freshwater shallow lakes from the Southeastern Pampa plain, Argentina

Molluscan taphonomic patterns below the sediment-water interface in three freshwater shallow lakes from the Southeastern Pampa Plain, Argentina (Nahuel Ruca´, Las Mostazas, and Los Carpinchos), were analyzed in order to explore the taphonomic alteration suffered by mollusks with depth and determine if this taphonomic alteration varied locally within lakes or between them. Short cores (approximately 30 cm) from littoral environment as well as open water were sampled in each lake. Nine mollusk species were identified: Heleobia parchappii, H. australis, Biomphalaria peregrina, Uncancylus concentricus, Musculium argentinum, Drepanotrema kermatoides, Succinea meridionalis, Antillorbis nordestensis, and Pomacea canaliculata. The highest percentage of moisture, organic matter and carbonates as well as less alkaline pH were recorded at the top of the cores and in littoral environments, indicating less favorable conditions for preservation. Results suggest that the taphonomically active zone occupies the first 10 cm below the sediment-water interface.Fil: Cristini, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: de Francesco, Claudio German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Taphonomic analysis of mollusks below the sediment-water interface in Nahuel Rucá lake (Buenos Aires Province, Argentina)

Se analizó la preservación de los restos de moluscos por debajo de la interfase agua-sedimento en la laguna Nahuel Rucá (37°37’S-57°25’O) con el objetivo de determinar el grado de alteración tafonómica y estimar la extensión de la zona tafonómicamente activa (TAZ). Para ello se realizó una descripción de los patrones de preservación observados en cinco testigos extraídos de la zona litoral y se evaluó el efecto de la disolución de los restos a diferentes profundidades y en presencia o ausencia de perióstraco, por medio de un experimento de campo. En todos los testigos los restos recuperados estuvieron dominados por fragmentos. En total se identificaron 7 especies: Biomphalaria peregrina (d’Orbigny, 1835), Drepanotrema kermatoides (d’Orbigny,1835), Heleobia australis (d’Orbigny, 1835), H. parchappii (d’Orbigny, 1835), Pomacea canaliculata (Lamarck, 1801), Uncancylus concentricus (d’Orbigny, 1835) y Musculium argentinum (d’Orbigny, 1835). Se concluye que la TAZ se extiende desde la superficie hasta aproximadamente 25 cm de profundidad. La mayor destrucción tiene lugar en los primeros 10 cm y disminuye gradualmente con la profundidad. De manera similar, la riqueza específica y la abundancia de los restos disminuyen a lo largo de la TAZ, preservándose solamente H. parchappii y fragmentos indeterminables. El efecto de la disolución que tiene lugar en la TAZ es mayor en aquellas conchas que carecen de perióstraco. Sin embargo, no se observaron diferencias en la disolución con la profundidad.The preservation of mollusk remains below the sediment-water interface in Nahuel Rucá lake (37°37′S–57°25′W) was analyzed in order to determine the degree of taphonomic alteration and to estimate the vertical extension of the taphonomically active zone (TAZ). To achieve that, the preservation patterns observed in five cores sampled from the litoral zone were described, and the effect of depth and presence of periostracum on shell dissolution was assessed by means of a field experiment. In all cores the recovered remains were dominated by fragments. Seven species were found: Biomphalaria peregrina (d’Orbigny, 1835), Drepanotrema kermatoides (d’Orbigny, 1835), Heleobia australis (d’Orbigny, 1835), H. parchappii (d’Orbigny, 1835), Pomacea canaliculata (Lamarck, 1801), Uncancylus concentricus (d’Orbigny, 1835) and Musculium argentinum (d’Orbigny, 1835). We concluded that the TAZ extends from the surface to a depth of approximately 25 cm. The highest destruction takes place in the first 10 cm and decreases gradually with depth. In a similar way, specific richness and abundance decrease downward through the TAZ, and only H. parchappii and unidentified fragments are found near the bottom. Dissolution was higher in shells without periostracum. No differences in dissolution were observed with depth.Fil: Cristini, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: de Francesco, Claudio German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Taphonomic field experiment in a freshwater shallow lake: alteration of gastropod shells below the sediment–water interface

We conducted a taphonomic field experiment to evaluate the effects of (1) depth below the sediment-water interface (SWI) and (2) time of exposure on the accrual of damage (particularly through dissolution) to empty mollusc shells in freshwater environments. The experiment, which lasted 30 months, was carried out in the littoral area of Lake Nahuel Rucá, a shallow freshwater lake in the Pampa plain of Argentina. Bags (0.5-cm mesh) containing empty, cleaned shells of the freshwater gastropods Heleobia parchappii, Biomphalaria peregrina and Pomacea canaliculata were buried at three different depths (5, 20 and 35 cm) below the SWI. Damage was assessed every 3 months. All experimental shells exhibited fine-scale surface alteration, but the extent of this damage was relatively low, even in shells recovered after 30 months of exposure. Most of the damage consisted of minor pitting. For H. parchappii and B. peregrina, shell surface alteration varied significantly with depth, but not with time; in both species, alteration occurred mainly at the beginning of the experiment. For P. canaliculata, shell surface alteration varied significantly only with respect to time and this was the case for all three burial depths. All shells of this species exhibited a lower level of damage than what was observed for H. parchappii and B. peregrina. These differences may be related to the fact that P. canaliculata is characterized by a larger and thicker shell than the other two species. The shell attributes of larger size and greater thickness are known to confer a greater resistance to shell dissolution. In addition, the reactive surface area available for dissolution varies with shell size. Larger-sized shells have a lower potential for dissolution than smaller shells due to their lower surface-Area-To-volume ratio. In contrast, species such as H. parchappii and B. peregrina, which have smaller and thinner shells, are likely to be more rapidly destroyed because they are more vulnerable to dissolution and have less preservation potential. Our results demonstrate that dissolution is a significant taphonomic process affecting shells even during burial and that the influence of dissolution on shell alteration might be significant in cases of long persistence within the taphonomically active zone. Consequently, we suggest that when working on taphofacies in the context of aquatic environments, assessments of taphonomic alteration should include changes at and below the SWI.Fil: Cristini, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: de Francesco, Claudio German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Shell strength of freshwater molluscs and its implication on preservation potential

Shell strength of the modern freshwater molluscs Heleobia parchappii, Biomphalaria peregrina, Uncancylus concentricus, Musculium argentinum, Physa acuta, Succinea meridionalis and Pomacea canaliculata was quantified through load measurements and analysed using Weibull distribution, a statistical method used for brittle materials. In this study, we defined shell strength as the maximum compressive force required to break a shell per unit of resistant area, which is known as mechanical tension or stress. Intrinsic properties of shells were also measured through mineralogical and morphological characterisation. Shells were mainly composed of aragonite and varied in size and shell thickness, being P. canaliculata (biovolume = 104 mm3) the largest and H. australis and H. parchappii (3.35 and 7.93 mm3, respectively) the smallest ones. The dominant microstructure was cross-lamellar, with layers that varied between one and four. The organic matter of the matrix varied between 1.58% and 4.24%. Shell strength differs among mollusc species. Smallest species have higher shell strength than larger ones because they have a smaller resistant area on which the load is applied, and therefore the resulting value of fracture stress increases abruptly. This may explain the dominance of H. parchappii in death and fossil assemblages from Pampa sediments.Fil: Cristini, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Frontini, Patricia Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Ballarre, Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; Argentin

Mollusk successions of holocene shallow-lake deposits from the southeastern Pampa plain, Argentina

We analyzed variations in taxonomic composition, abundance, and preservation of freshwater mollusks during the mid- to late Holocene in three shallow lakes of the southeastern Pampa plain. Mollusks were obtained from core samples (110–140 cm long) from the deepest part of the lakes, and sampled at 1 cm intervals. Six species were identified: Heleobia australis, Heleobia parchappii, Biomphalaria peregrina, Uncancylus concentricus, Succinea meridionalis, and Antillorbis nordestensis. Assemblages were dominated by H. parchappii, which displayed continuous and complete records in the three sections. With the exception of H. australis, fossil assemblages were represented by the same species that today inhabit Pampean lakes and preserved the same rank order of abundance as modern communities. A similar pattern of variation in mollusk assemblage composition was recognized in the three successions, which initiated prior to circa 6000 cal. year B.P, with assemblages composed of H. parchappii and S. meridionalis at low abundances. A broad expansion of H. parchappii occurred between circa 6000 and 5400 cal. year B.P., and the species rapidly dominated the whole malacofauna. At circa 5400 cal. year B.P., the freshwater B. peregrina was recorded for the first time, and its abundance gradually increased until circa 3600 cal. year B.P. At ∼3700 cal. year B.P., the estuarine H. australis was recorded. The arrival of the freshwater U. concentricus occurred at ∼1697 cal. year B.P. Finally, only H. parchappii and B. peregrina were represented in the topmost levels (younger than ∼736 cal. year B.P.). Changes in mollusk composition were mostly related to changes in water salinity, which brings a historical perspective to understanding the modern dominance of the euryhaline H. parchappii in these lakes. Shell preservation became favored when water bodies developed brackish conditions.Fil: de Francesco, Claudio German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Tietze, Eleonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Cristini, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Water geochemistry of shallow lakes from the southeastern Pampa plain, Argentina and their implications on mollusk shells preservation

A seasonal sampling of sediments, column and interstitial water for physico-chemical analysis were performed in littoral and open water areas in three freshwater shallow lakes (Nahuel Rucá, Las Mostazas and Los Carpinchos) from Southeastern Pampa plain, Argentina. The main objective of the present study is to evaluate how the characteristics of the depositional environments could be affecting mollusk shell preservation. These lakes are very shallow (2 m) and are characterized by an extensive littoral area, dominated by the emergent macrophyte Schoenoplectus californicus, which forms a complete ring around the lake, and an open water area, in general free of vegetation. Five samples of sediments in each compartment were extracted for analysis of pH, moisture, organic matter and carbonates content using a gravity corer, while five samples from column and interstitial water were extracted for chemical analysis (pH, conductivity, major ions, minor ions and hardness). Besides, calcite and aragonite saturation indices and the redox potential were calculated for each lake. The results show the significant impact of water chemistry and redox conditions on the preservation potential of freshwater mollusk and consequently in the quality of paleonvironmental reconstruction based on the biological record from the study region. The higher concentration of organic matter and lower pH registered in the littoral area, mainly during warm months (autumn and summer), suggest worst environments for mollusk preservation, compared to open waters. Moreover, water geochemistry analysis showed aragonite and calcite indices near equilibrium or slightly subsaturated in interstitial water associated with more acid pHs, while column water is strongly oversaturated related to alkaline pHs. These results suggest that carbonate remains within sediments will be subject to dissolution affecting negatively their preservation potential. However, mollusk shells in contact with the column water are not expected to be dissolved.Fil: Cristini, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Tietze, Eleonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: de Francesco, Claudio German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Martinez, Daniel Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Differential preservation of freshwater diatoms and mollusks in late Holocene sediments: paleoenvironmental implications

One of the limitations of paleoenvironmental reconstructions based on multiple bioindicators is a lack of knowledge on the differential preservation of hard parts, which may lead to biases in interpretation. This is particularly important when biological proxies differ in their intrinsic properties, such as skeletal mineralogy or size. We explored and compared the preservational patterns of siliceous (diatoms) and carbonate (mollusks) fossils during the late Holocene (ca. 4000 cal. years B.P.) in two lacustrine sedimentary successions from Argentina (Nahuel Rucá and Hinojales–San Leoncio). Fragmentation and fine-scale surface-alteration indices were calculated on two target species: the diatom Cyclotella meneghiniana Kützing and the snail Heleobia parchappii (d'Orbigny, 1835). The taphonomic data were smoothed along depth with a locally weighted regression (LOESS) and statistically compared using Spearman correlations. Additionally, past environmental conditions were inferred from the autoecology of the dominant taxa. Diatoms and mollusks displayed similar tendencies in fragmentation, characterized by a gradual decrease of breakage toward the top of the successions. On the other hand, trends in surface preservation were opposite. Diatoms exhibited higher alteration in the oldest sedimentary levels, characterized as saline and less-productive water bodies, while mollusks were more altered at the topmost levels, characterized as freshwater highly productive lakes. This contrasting response of both indicators can be interpreted as a consequence of the differential reaction of carbonate and silica to dissolution agents acting in fresh and saline water. Hence, the accuracy of the paleoenvironmental information provided by both indicators under these contrasting conditions probably would be affected by the taphonomic biases suffered, which highlight the relevance of including taphonomic traits in Quaternary paleoenvironmental or paleoclimatic studies.Fil: Hassan, Gabriela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Tietze, Eleonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Cristini, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: de Francesco, Claudio German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencia Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin

Actualistic taphonomy of freshwater molluscs from the Argentine Pampas: An overview of recent research progress

Historically, the development of taphonomic studies in freshwater environments has been scarce and mainly restricted to the Northern Hemisphere, with almost no information on how taphonomic processes work (and eventually differ) in the Southern Hemisphere. We present here an overview of the main results obtained in actualistic taphonomic studies on freshwater mollusks conducted in the Pampa Plain of Argentina, since 2008. The research included patterns of distribution of live and dead mollusks, live-dead fidelity at local and regional scales and dead and fossil shell preservation. Studies were conducted above and below the sediment-water interface, including both descriptive and experimental approaches.Fil: de Francesco, Claudio German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Tietze, Eleonor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Cristini, Paula Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Hassan, Gabriela Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; Argentin