Within the field of study of the morphology of the crustaceans, Garm & Hoeg (2000) state that... more Within the field of study of the morphology of the crustaceans, Garm & Hoeg (2000) state that one of the most interesting lines of research because of its complexity, is addressed by the analysis of the mouthparts. According to other authors (Cartes, 1993), this complexity has played a fundamental role in the colonization success of this group, showing a remarkable range of food options. Aegla uruguayana is a freshwater anomuran crab that lives in lotic and lenitic freshwater environments of the southern state of Río Grande do Sul in Brazil, and in Uruguay and central and northwest Argentina (Bond-Buckup & Buckup, 1994). This decapod belongs to the unique family of anomurans that colonized freshwater environments (Schmitt, 1942). The aim of this work is to analyze the patterns of the mandible of A. uruguayana on specimens of various sizes to determine if juveniles and adults may have different food options. Digital pictures of all specimens were taken using a Moticam 1000 digital microscope camera. Seven landmarks and three semi-landmarks were recorded on the dorsal view of the cephalothorax through the tpsDig program (Rohlf, 2004). Configurations were superimposed through the Generalized Procrustes Analysis (Rohlf & Slice, 1999) in the tpsRelw program (Rohlf, 2005). Shape variation between samples was first explored through Relative Warp analysis. The mandible shape differed among dietary classes (juveniles, sub-adults and adults). The RW 1 showed that the smooth molar process was the dominant deformations. Moreover the RW2 reflected shape variation in the mandible according to molt cycle stage. The MANCOVA reveled significant differences (P<0, 05) between juveniles, sub-adults and adults. Thus, the temporal proximity to the phenomenon of moulting and the degree of wear of the incisor process could explain this pattern. This could be explained by the low frequency of consumption of plant debris in juveniles compared with adults. Based on these results, it is possible to argue that mechanical destruction of this item would accelerate the erosion of the mandible. Adding to this, the longest period of time between ecdysis events maybe explain these results.Fil: Williner, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Giri, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin
The family Trichodactylidae characterizes the aquatic environments of the plain, being the Paraná... more The family Trichodactylidae characterizes the aquatic environments of the plain, being the Paraná River an important system in the continent. The taxonomic studies of this group were based on carapace ornamentation and male gonopod morphology. THe aim of this study was to explore an alternative way of taxonomic identification of the members of the Trichodactylidae family, including females. This studie focused on the application of geometric morphometric analysis to the carapace of representative species from Middle parana River.Fil: Giri, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Williner, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin
The hydrological regime is the main factor governing the functioning of floodplain rivers. A full... more The hydrological regime is the main factor governing the functioning of floodplain rivers. A full comprehension of its dynamic leads to a better understanding of the system’s behaviour and of the proper methods that must be used. We analysed the daily water level of the Paraná River during the last century at three gauge stations using linear and non-linear tools to characterise the hydrological dynamic and to analyse to what extent chaotic behaviour prevails. The three water level time series were characterised as non-linear and non-stationary by power spectrum, autocorrelation function, and surrogate test analyses. A strange attractor was developed when the phase space was reconstructed, having a low dimensional chaos supported by correlation dimension, positive maximum Lyapunov exponents, and recurrence quantification analysis. In line with this, the system resulted unpredictable with a threshold by sample entropy, and with an intermediate hydrological complexity, while Hurst exp...
DECAPOD CRUSTACEANS OF ARGENTINEAN LITTORAL FLUVIAL. The decapods is a group of crustaceans that ... more DECAPOD CRUSTACEANS OF ARGENTINEAN LITTORAL FLUVIAL. The decapods is a group of crustaceans that has not been deeply studied in this freshwater environment, although during the last years there are some more papers making reference to these animals. In this work, It is showed a list of the Superior Crustaceans Superorden Eucarida that inhabits Argentinean territory. The data is based on some observations carried out by this work group and bibliography. Results and observations done on the biodiversity, trophic ecology, distribution , activity, growth, behaviour, ecotoxicology show it is developed as well as other work lines carried out by other investigators. This wide range of information has given enough material to argue about the importance of this group in the Argentinean Littoral Fluvial and even more to make people aware of the need for an increase in the searching. Introducción El orden Decapoda integra junto con otros dos ordenes (Amphionidacea y Euphasiaceae) el Superorden...
Cryptic species are a major challenge for morphologically based species identification. Molecular... more Cryptic species are a major challenge for morphologically based species identification. Molecular approaches to species delimitation can be a valuable tool to provide preliminary taxonomic hypotheses and significantly complements morphological taxonomy. In South America, the freshwater crabs of the genus Aegla have sparked much interest as they are key species in the often‐endangered freshwater ecosystems and themselves are often considered endangered species. Morphological similarity among Aegla species is not always positively correlated with genetic relatedness and growing evidence suggests that several putative single taxa are actually assemblages of cryptic species. We coupled broad geographically sampling (Argentina, Brazil and Uruguay) with multilocus (COI, 16S and ANT) phylogenies to investigate the diversity of Aegla uruguayana. Our species delimitation analyses suggested that 19 aeglid populations form a well‐supported clade, although individuals from 10 populations possib...
We analyze whether ontogenetic diet change in Aegla uruguayana Schmitt, 1942 is related to the mo... more We analyze whether ontogenetic diet change in Aegla uruguayana Schmitt, 1942 is related to the morphological changes in chelae and mandibles. We use a combination of scanning electron microscope (SEM) observation, dietary composition analysis (stomach observation, trophic niche amplitude, trophic overlap, and feeding strategy), and geometric morphometric tools (discriminant analysis and two-block partial least squares analysis). The two structures analyzed by SEM show differences between juvenile and adult specimens, both in their cuticle and morphology specializations. In juveniles, the absence of the lobular tooth is the notable feature. However, in adult sizes, it is marked development. Both groups have simple setae with infracuticular articulation and denticles with different arrangements between groups. In the incisive mandible process, the teeth and spines present sharper points in juveniles and considerable wear in adults. Aegla uruguayana presented two trophic strategies: a ...
The presence, density, and distribution pattern of a species in a particular space and time resul... more The presence, density, and distribution pattern of a species in a particular space and time result from evolutionary and ecological processes. We evaluated the density and spatial distribution pattern of the freshwater anomuran crab, Aegla uruguayanaSchmitt, 1942, in relation to temporal and spatial scales. The temporal scale followed a seasonal analysis, and the space scale was evaluated from the study of three streams located in different provinces of Argentina. Specimens were collected in four sampling campaigns during spring, summer, autumn, and winter in three temperate freshwater environments of the La Plata Basin, Argentina, using 1 m2 sampling units. The density varied according to the studied populations and was not by seasonality. The distribution pattern was not influenced by the evaluated scales. The A. uruguayana populations presented a clumped pattern showing a negative binomial distribution. A possible cause of such a pattern is the strong environmental heterogeneity ...
PurposeThe study was carried out in a wetland of the Middle Paraná River system, Argentina, in or... more PurposeThe study was carried out in a wetland of the Middle Paraná River system, Argentina, in order to evaluate the processes associated with the decomposition of manure, which includes changes in chemical composition, nutrient release of manure, and colonization of invertebrates. We also compared the invertebrate assemblage that colonized manure with that present in the benthos of the wetland.Materials and methodsNylon bags were filled with fresh cattle manure and anchored to the littoral zone of the wetland. Six bags were collected after 1, 2, 6, 14, 21, 28, 33, 55, and 79 days: three for invertebrate determination and the other three bags for determination of dry mass and chemical analyses. The nutrient content, cellulose, lignin, and total phenolic compounds of manure were determined. In addition, the leachate of manure was collected for nutrient analyses. Samples of the wetland benthic sediment were collected for benthic invertebrate determination and particle size analyses. Spearman rank correlation was used to evaluate the relationship between chemical compounds of manure and breakdown rate. Principal component analysis was used to explore invertebrate assemblage composition of manure and sediment during the experiment.Results and discussionLimnodrilus, Dero, and Chironomus were dominant in the manure. Gatherer-collector was the dominant group in the manure, comprising almost 95 % of the total density of invertebrates. Breakdown rate was significantly related with nutrients, cellulose and total phenolics of manure. An ordination plot showed changes in invertebrate assemblages of manure and sediment samples over time.ConclusionsThis study provides new insight on the importance of manure as a substrate for macroinvertebrate colonization. Cattle manure needs to be considered as a potential source of nutrients for aquatic systems and a substrate for invertebrate assemblages.
Within the field of study of the morphology of the crustaceans, Garm & Hoeg (2000) state that... more Within the field of study of the morphology of the crustaceans, Garm & Hoeg (2000) state that one of the most interesting lines of research because of its complexity, is addressed by the analysis of the mouthparts. According to other authors (Cartes, 1993), this complexity has played a fundamental role in the colonization success of this group, showing a remarkable range of food options. Aegla uruguayana is a freshwater anomuran crab that lives in lotic and lenitic freshwater environments of the southern state of Río Grande do Sul in Brazil, and in Uruguay and central and northwest Argentina (Bond-Buckup & Buckup, 1994). This decapod belongs to the unique family of anomurans that colonized freshwater environments (Schmitt, 1942). The aim of this work is to analyze the patterns of the mandible of A. uruguayana on specimens of various sizes to determine if juveniles and adults may have different food options. Digital pictures of all specimens were taken using a Moticam 1000 digital microscope camera. Seven landmarks and three semi-landmarks were recorded on the dorsal view of the cephalothorax through the tpsDig program (Rohlf, 2004). Configurations were superimposed through the Generalized Procrustes Analysis (Rohlf & Slice, 1999) in the tpsRelw program (Rohlf, 2005). Shape variation between samples was first explored through Relative Warp analysis. The mandible shape differed among dietary classes (juveniles, sub-adults and adults). The RW 1 showed that the smooth molar process was the dominant deformations. Moreover the RW2 reflected shape variation in the mandible according to molt cycle stage. The MANCOVA reveled significant differences (P<0, 05) between juveniles, sub-adults and adults. Thus, the temporal proximity to the phenomenon of moulting and the degree of wear of the incisor process could explain this pattern. This could be explained by the low frequency of consumption of plant debris in juveniles compared with adults. Based on these results, it is possible to argue that mechanical destruction of this item would accelerate the erosion of the mandible. Adding to this, the longest period of time between ecdysis events maybe explain these results.Fil: Williner, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Giri, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin
The family Trichodactylidae characterizes the aquatic environments of the plain, being the Paraná... more The family Trichodactylidae characterizes the aquatic environments of the plain, being the Paraná River an important system in the continent. The taxonomic studies of this group were based on carapace ornamentation and male gonopod morphology. THe aim of this study was to explore an alternative way of taxonomic identification of the members of the Trichodactylidae family, including females. This studie focused on the application of geometric morphometric analysis to the carapace of representative species from Middle parana River.Fil: Giri, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Williner, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; ArgentinaFil: Collins, Pablo Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto Nacional de Limnología. Universidad Nacional del Litoral. Instituto Nacional de Limnología; Argentin
The hydrological regime is the main factor governing the functioning of floodplain rivers. A full... more The hydrological regime is the main factor governing the functioning of floodplain rivers. A full comprehension of its dynamic leads to a better understanding of the system’s behaviour and of the proper methods that must be used. We analysed the daily water level of the Paraná River during the last century at three gauge stations using linear and non-linear tools to characterise the hydrological dynamic and to analyse to what extent chaotic behaviour prevails. The three water level time series were characterised as non-linear and non-stationary by power spectrum, autocorrelation function, and surrogate test analyses. A strange attractor was developed when the phase space was reconstructed, having a low dimensional chaos supported by correlation dimension, positive maximum Lyapunov exponents, and recurrence quantification analysis. In line with this, the system resulted unpredictable with a threshold by sample entropy, and with an intermediate hydrological complexity, while Hurst exp...
DECAPOD CRUSTACEANS OF ARGENTINEAN LITTORAL FLUVIAL. The decapods is a group of crustaceans that ... more DECAPOD CRUSTACEANS OF ARGENTINEAN LITTORAL FLUVIAL. The decapods is a group of crustaceans that has not been deeply studied in this freshwater environment, although during the last years there are some more papers making reference to these animals. In this work, It is showed a list of the Superior Crustaceans Superorden Eucarida that inhabits Argentinean territory. The data is based on some observations carried out by this work group and bibliography. Results and observations done on the biodiversity, trophic ecology, distribution , activity, growth, behaviour, ecotoxicology show it is developed as well as other work lines carried out by other investigators. This wide range of information has given enough material to argue about the importance of this group in the Argentinean Littoral Fluvial and even more to make people aware of the need for an increase in the searching. Introducción El orden Decapoda integra junto con otros dos ordenes (Amphionidacea y Euphasiaceae) el Superorden...
Cryptic species are a major challenge for morphologically based species identification. Molecular... more Cryptic species are a major challenge for morphologically based species identification. Molecular approaches to species delimitation can be a valuable tool to provide preliminary taxonomic hypotheses and significantly complements morphological taxonomy. In South America, the freshwater crabs of the genus Aegla have sparked much interest as they are key species in the often‐endangered freshwater ecosystems and themselves are often considered endangered species. Morphological similarity among Aegla species is not always positively correlated with genetic relatedness and growing evidence suggests that several putative single taxa are actually assemblages of cryptic species. We coupled broad geographically sampling (Argentina, Brazil and Uruguay) with multilocus (COI, 16S and ANT) phylogenies to investigate the diversity of Aegla uruguayana. Our species delimitation analyses suggested that 19 aeglid populations form a well‐supported clade, although individuals from 10 populations possib...
We analyze whether ontogenetic diet change in Aegla uruguayana Schmitt, 1942 is related to the mo... more We analyze whether ontogenetic diet change in Aegla uruguayana Schmitt, 1942 is related to the morphological changes in chelae and mandibles. We use a combination of scanning electron microscope (SEM) observation, dietary composition analysis (stomach observation, trophic niche amplitude, trophic overlap, and feeding strategy), and geometric morphometric tools (discriminant analysis and two-block partial least squares analysis). The two structures analyzed by SEM show differences between juvenile and adult specimens, both in their cuticle and morphology specializations. In juveniles, the absence of the lobular tooth is the notable feature. However, in adult sizes, it is marked development. Both groups have simple setae with infracuticular articulation and denticles with different arrangements between groups. In the incisive mandible process, the teeth and spines present sharper points in juveniles and considerable wear in adults. Aegla uruguayana presented two trophic strategies: a ...
The presence, density, and distribution pattern of a species in a particular space and time resul... more The presence, density, and distribution pattern of a species in a particular space and time result from evolutionary and ecological processes. We evaluated the density and spatial distribution pattern of the freshwater anomuran crab, Aegla uruguayanaSchmitt, 1942, in relation to temporal and spatial scales. The temporal scale followed a seasonal analysis, and the space scale was evaluated from the study of three streams located in different provinces of Argentina. Specimens were collected in four sampling campaigns during spring, summer, autumn, and winter in three temperate freshwater environments of the La Plata Basin, Argentina, using 1 m2 sampling units. The density varied according to the studied populations and was not by seasonality. The distribution pattern was not influenced by the evaluated scales. The A. uruguayana populations presented a clumped pattern showing a negative binomial distribution. A possible cause of such a pattern is the strong environmental heterogeneity ...
PurposeThe study was carried out in a wetland of the Middle Paraná River system, Argentina, in or... more PurposeThe study was carried out in a wetland of the Middle Paraná River system, Argentina, in order to evaluate the processes associated with the decomposition of manure, which includes changes in chemical composition, nutrient release of manure, and colonization of invertebrates. We also compared the invertebrate assemblage that colonized manure with that present in the benthos of the wetland.Materials and methodsNylon bags were filled with fresh cattle manure and anchored to the littoral zone of the wetland. Six bags were collected after 1, 2, 6, 14, 21, 28, 33, 55, and 79 days: three for invertebrate determination and the other three bags for determination of dry mass and chemical analyses. The nutrient content, cellulose, lignin, and total phenolic compounds of manure were determined. In addition, the leachate of manure was collected for nutrient analyses. Samples of the wetland benthic sediment were collected for benthic invertebrate determination and particle size analyses. Spearman rank correlation was used to evaluate the relationship between chemical compounds of manure and breakdown rate. Principal component analysis was used to explore invertebrate assemblage composition of manure and sediment during the experiment.Results and discussionLimnodrilus, Dero, and Chironomus were dominant in the manure. Gatherer-collector was the dominant group in the manure, comprising almost 95 % of the total density of invertebrates. Breakdown rate was significantly related with nutrients, cellulose and total phenolics of manure. An ordination plot showed changes in invertebrate assemblages of manure and sediment samples over time.ConclusionsThis study provides new insight on the importance of manure as a substrate for macroinvertebrate colonization. Cattle manure needs to be considered as a potential source of nutrients for aquatic systems and a substrate for invertebrate assemblages.
Berrón, M., G. Parera y S. Yuan (comp.) XVII Congreso Nacional de Filosofía (AFRA). Santa Fe: UNL (ebook), pp. 775–783. ISBN 978-987-692-149-7, 2017
La contribución discute el alegado carácter único del lenguaje humano respecto de otras formas de... more La contribución discute el alegado carácter único del lenguaje humano respecto de otras formas de comunicación identificables en la naturaleza.
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