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The study of the cephalic shape of crocodilian is relevant in the fields of ecology, systematics, evolution, and conservation. Therefore, the integration of geometric analysis within quantitative genetics allows the evaluation of the inheritable shape components. In this study, the dorsal cephalic region of 210 Caiman latirostris hatchlings was analyzed from seven populations in Santa Fe, Argentina, to detect intra-, and inter-population phenotypic variability, and to determine the heritability of biological shape and size, using newly available geometric morphometric tools. The principal component analysis showed two configurations of cephalic shape that could be related to sexual dimorphism. In the canonical variate analysis, Procrustes distances between groups indicated that there are differences in shape among populations. Furthermore, the method of partial least squares indicated a covariation between cephalic shape and environmental variables. Regarding to CS of the skull we found significant differences among populations, moreover the partial least squares was also significant. Estimates of the heritability of shape and size were high, indicating that the components of these features are susceptible to the selection. Fil: Imhoff, Carolina Guadalupe. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Departamento de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina 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; Argentina Fil: Siroski, Pablo Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Amavet, Patricia Susana. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias. Departamento de Ciencias Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

An accommodating monetary policy followed by a sudden increase of the short term interest rate often leads to a bubble burst and to an economic slowdown. Two examples are the Great Depression of 1929 and the Great Recession of 2008. Through the implementation of an Agent Based Model with a financial accelerator mechanism we are able to study the relationship between monetary policy and large scale crisis events. The main results can be summarized as follow: a) sudden and sharp increases of the policy rate can generate recessions; b) after a crisis, returning too soon and too quickly to a normal monetary policy regime can generate a \double dip" recession, while c) keeping the short term interest rate anchored to the zero lower bound in the short run can successfully avoid a further slowdown.

The great depression of 1929 and the great financial crisis of 2008 have been the two big events of the last 75 years. Not only have they produced serious economic consequences but they also changed our view of economics and policymaking. The aim of this work is to compare these two great crises and highlight similarities as well as differences. Monetary policy, the exchange rate system and the role of the banks are our fields of investigation. Our findings are that two big events have more similarities than dissimilarities.

South America has been influenced by different geoclimatic events ever since its separation from Africa. The inland water fauna has evolved in response to the changing landscape. Currently, there are indications of variations in populations, occurring to different degrees that would indicate a clinal pattern in morphology. Among South America's fauna, the freshwater anomuran, Aegla, is an enigmatic group as a result of its endemicity and is composed of only one genus. Of all the species in this family, Aegla uruguayana has the broadest distribution. Its native habitats have been influenced by several marine transgressions during the Miocene–Quaternary Periods; thus, it is likely that their current distribution has been more recent. Its habitat spreads across a number of isolated basins and sub-basins that display distinct degrees of isolation/connection, making clinal variation patterns in the morphology of this species possible. The present study aimed to evaluate the pattern of carapace shape variation in A. uruguayana and how it relates to the isolation and/or connection of populations from different basins and sub-basins, allowing the determination of any extant clinal patterns. The specimens studied belong to 25 separate populations, representing all areas in which the species currently exists. A total of 523 crabs were analyzed. We identified 13 landmarks and four semi-landmarks in the carapace. The aeglids were divided into seven size intervals to avoid an allometry effect. In each size category, shape relationships analyzed by principal component analysis suggest a geographical pattern corresponding to the distribution of the populations studied. An evaluation of covariation between body shape and geographical coordinates reveals a strong pattern and shows that population distribution had a significant effect on species morphology. Additionally, according to covariance analysis, the variation in shape was not associated with the environmental variables studied. We observed a clinal pattern throughout the species distribution, which could be attributed to genetic drift. It is possible that this process is being amplified by the geographical isolation of the basins, differences in environmental characteristics, and low dispersal ability. 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; Argentina. Universidad Nacional del Litoral. Facultad de Humanidades y Ciencias; Argentina Fil: 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; Argentina. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina

The aim of this paper is to assess the impact of the interbank market on the business cycle fluctuations. In order to do that, we build a DSGE model with heterogeneous households and banks. The surplus bank can allocate its resources between interbank lending and risk free government bonds. This portfolio choice is affected by an exogenous counterpart risk shock on the interbank lending. An increase of the counterpart risk diverts funds from the interbank markets toward the risk free market. This mechanism allow us to capture the collapse of the interbank market and the fly to quality mechanism underlying the 2007 financial crisis. The main result is that an interbank riskiness shock seems to explain part of the 2007 downturn and especially the rise of the interest rates on the credit market during and just after the financial turmoil.

Sylviocarcinus australis Magalh��es & T��rkay, 1996 (Fig. 1 c) Sylviocarcinus australis (Magalh��es & T��rkay 1996) ��� Magalh��es and T��rkay (1996 b): 238 p., fig. 129 (complete synonymy). Diagnosis. Each anterolateral border of carapace: four distinctive teeth. Abdominal segments III���VI: fused. Male plp 1: subdistal lobe poorly developed with a subterminal spine field. Basal lobe: more important than in the other crabs (Fig. 1 c). Habitat. This species was observed in environments similar to those of S. pictus and Z. collastinensis, using caves and tree trunks. Some crabs were also observed within aquatic vegetation, mainly of the Paspalum genus. Material examined. Eleven male and four female specimens; carapace width: 41.8 mm (SD 5.38). Two males and one female, FANM N�� MFA ��� ZI ��� N�� 348, Salado River (Argentina, Santa Fe, Santo Tom��, 31 �� 39 ���S 60 �� 45 ���W), without collection date, Collins coll.; two males and one female, ML-INALI N�� 12, Ubajay stream (Argentina, Santa Fe, Rinc��n, 31 �� 37 ���S 60 �� 36 ���W), 1.12.0 5, Collins coll.; three males and one female, ML-INALI N�� 13, San Javier River (Argentina, Santa Fe, 29 �� 13 ���S 59 �� 35 ���W), 30.11.0 5, Collins coll.; three males and one female, ML-INALI N�� 18, Malabrigo stream (Argentina, Santa Fe, 29 �� 26 ���S 59 �� 45 ���W), 30.11.0 5, Collins coll.; one male, ML-INALI N�� 18, Paran�� Mini stream (Argentina, Santa Fe, Villa Ocampo, 28 �� 32 ���S 59 �� 15 ���W), 29.11.0 5, Collins coll. Southern locations. Ubajay stream (31 �� 36 ���S 60 �� 34 ���W), Salado River (31 �� 39 ���S 60 �� 45 ���W), Paran�� River floodplain, Argentina. New distribution. Paraguay, Brazil and Argentina, Coronda River south limit (31 �� 57 ��� S 60 �� 54 ���W) (Fig. 2 c)., Published as part of Collins, Pablo A., Giri, Federico & Williner, Ver��nica, 2009, Range extension for three species of South American freshwater crabs (Crustacea: Decapoda: Trichodactylidae), pp. 49-54 in Zootaxa 1977 on page 52, DOI: 10.5281/zenodo.185199, {"references":["Magalhaes, C. & Turkay, M. (1996 b) Taxonomy of the Neotropical freshwater crab family Trichodactylidae II. The genera Forsteria, Melocarcinus, Sylviocarcinus, and Zilchiopsis (Crustacea: Decapoda: Brachyura). Senckenbergiana Biologica, 75 (1 / 2), 97 - 130."]}

Sylviocarcinus pictus (Milne-Edwards, 1853) (Fig. 1 b) Sylviocarcinus pictus (Milne-Edwards, 1853) ��� Magalh��es & T��rkay 1996 b: 244 p., fig. 135 (complete synonymy). Diagnosis. Carapace: 4 distinctive teeth on each anterolateral border. Abdominal segments III���VI of male: fused. The male plp 1 bends following a regular curve to the right, subdistal lobe with subterminal spine field strongly developed, basal lobe: insignificant (Fig. 1 b). Habitat. This species was observed in caves and under tree trunks. In other caves, the crab Zilchiopsis collastinensis was mainly found. Material examined. Seven males, one female and eight juveniles; carapace width: 43.5 mm (SD 6.68) two males, one female and four juveniles, FANM N�� MFA - ZI - N�� 271, Santa Fe stream (Argentina, Santa Fe, 31 �� 38 'S 60 �� 39 'W), 22.3. 65, non-specific collector; two males and four juveniles, ML-INALI N�� B - 9, Coronda River (Argentina, Santa Fe, Sauce Viejo, 31 �� 48 'S 60 �� 46 'W), 13.12.0 0, Collins coll.; one male, ML- INALI N�� B 10, Set��bal Lagoon (Argentina, Santa Fe, Colastin�� Sur, 31 �� 39 'S 60 �� 45 'W), 20.12.0 0, Collins coll.; one male ML-INALI N�� B 11, Salado River (Argentina, Santa Fe 31 �� 39 'S 60 �� 45 'W), 12.2.0 3, Regner coll.; one male, ML-INALI N�� B 15, El Limpio stream (Argentina, Santa Fe, Paranacito, 28 �� 5 ���S 59 ��09���W), 29.11.0 5, Collins coll. Southern locations. Set��bal lagoon (31 �� 35 'S 60 �� 39 'W), Coronda River (31 �� 48 'S 60 �� 46 'W) and Salado River (31 �� 39 'S 60 �� 45 'W), Paran�� River floodplain, Argentina. New distribution. Peru, Guyana, French Guyana, Paraguay, Bolivia, Brazil and Argentina, Coronda River south limits (31 �� 48 ���S 60 �� 46 ���W) (Fig. 2 b)., Published as part of Collins, Pablo A., Giri, Federico & Williner, Ver��nica, 2009, Range extension for three species of South American freshwater crabs (Crustacea: Decapoda: Trichodactylidae), pp. 49-54 in Zootaxa 1977 on page 51, DOI: 10.5281/zenodo.185199, {"references":["Milne-Edwards, A. (1853) Memoire sur la famille des Ocypodiens. Annales des Sciences Naturelles, 20 (3), 163 - 226.","Magalhaes, C. & Turkay, M. (1996 b) Taxonomy of the Neotropical freshwater crab family Trichodactylidae II. The genera Forsteria, Melocarcinus, Sylviocarcinus, and Zilchiopsis (Crustacea: Decapoda: Brachyura). Senckenbergiana Biologica, 75 (1 / 2), 97 - 130."]}

Dilocarcinus septemdentatus (Herbst, 1783) (Fig. 1 a) Dilocarcinus septemdentatus ��� Magalh��es 2003: 206 p., fig. 109. Diagnosis. Carapace: 6 distinctive teeth on each anterolateral border. Abdominal segments III���VI of males fused. Third abdominal segment with slight, smooth margin, without the distinction of a crest among the others abdominal segments. Male pleopod (plp 1) gently curving outwards, distal end extending beyond subterminal spine field, as long as spine field (Fig. 1 a). Habitat. This species was observed within aquatic vegetation, mainly Eicchornia crassipes, along with other crabs such as D. pagei, Trichodactylus borellianus. Material examined. Nine males and three females, carapace width 22.5 mm (SD 8.69 mm), FANM N�� MFA - ZI 347, Salado River) (Argentina, Santa Fe, Santo Tom��, 31 �� 39 'S 60 �� 45 'W), without collection date, Collins coll.; two males and one female, FANM N�� MFA - ZI 402, Colastin�� River (Argentina, Santa Fe, Colastin�� Sur, 31 �� 37 'S 60 �� 34 'W), 8.9. 63, Martinez; one male, ML-INALI N�� B 7, San Javier River (Argentina, Santa Fe, 29 �� 13 ���S 59 �� 35 ���W), 30.11.0 5, Collins coll.; one male, ML-INALI N�� B 8, Set��bal lagoon (Argentina, Santa Fe, Rinc��n, 31 �� 35 'S 60 �� 39 'W), 1.12.0 5, Collins coll.; one male, ML-INALI N�� B 16, Los Amores stream (Argentina, Santa Fe, 28 �� 51 ���S 59 �� 29 ���W), 29.11.0 5, Collins coll.; two males and two females ML-INALI N�� B 21, Parque del Sur lake (Argentina, Santa Fe, Santa Fe city, 31 �� 39 'S 60 �� 42 'W), 28.11.0 6, Collins. Southern locations. Set��bal Lagoon (31 �� 35 'S 60 �� 39 'W), Colastin�� River (31 �� 37 'S 60 �� 34 'W), Parque del Sur Lake (Santa Fe city) (31 �� 39 'S 60 �� 42 'W) and Salado River (31 �� 39 'S 60 �� 45 'W), Paran�� River floodplain, Argentina. New distribution. Paraguay, Brazil and Argentina, Salado River as southern limit (31 �� 39 ���S, 60 �� 45 ���W) (Fig. 2 a)., Published as part of Collins, Pablo A., Giri, Federico & Williner, Ver��nica, 2009, Range extension for three species of South American freshwater crabs (Crustacea: Decapoda: Trichodactylidae), pp. 49-54 in Zootaxa 1977 on page 50, DOI: 10.5281/zenodo.185199, {"references":["Herbst, J. F. W. (1783) Versuch einer Naturgeschichte der Krabben und Krebse nest einer systematischen Beschreibung ihrer verschiedenen Arten. Stralsund, Berlin & Stralsund. Vol. 1 - 3, 1 - 515.","Magalhaes, C. (2003) Familias Pseudothelpusidae e Trichodactylidae. In: Melo, G. A. S. (Ed.), Manual de identificacao dos Crustacea Decapoda de agua doce do Brasil. Loyola, Sao Paulo, pp. 143 - 287."]}

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

Los crustáceos decápodos dulciacuícolas de Argentina se agrupan en 4 familias: Sergestidae, Palaemonidae, Parastacidae, Aeglidae, Trichodactylidae. La diversidad y distribución de estas familias es resultado de millones de años de evolución junto a una intensa relación de los diferentes eventos geológicos e hidrológicos ocurridos en América del Sur. En este trabajo se presenta una síntesis sobre filogenia, aspectos biológicos, fisiológicos y ecológicos de estos grupos, como así también se establecen relaciones de estos aspectos con factores ambientales y con el ciclo hidrosedimentológico como macrofactor regulador. La información aquí revisada muestra que el nivel de agua y la conectividad de las lagunas influye sobre la disponibilidad de refugios y alimento, modificando las relaciones intra e interespecíficas. 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; Argentina 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; Argentina Fil: 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; Argentina

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; Argentina 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; Argentina Fil: 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; Argentina

The predator-prey relationship of Palaemonetes argentinus Nobili, 1901 and Culex pipiens s.l. larvae was studied under laboratory conditions. The prawns were separated in two groups, isolated and grouped ones. Mosquitoe larvae were offered to prawns in two forms, limited and unlimited offer to both groups. In the first analysis, values of predation did not differ significantly between males and females of P. argentinus. Predation in 24 h was 14,9 ± 4,2 larvae/prawn. A reduction of predation was observed with unlimited offer for the same hour, during all the experiment. Predation with unlimited offer was higher on the first day than on the second, but returned to high values on the third day, for both groups. In the grouped experiment, predation with limited offer was total on the first days, decreasing to the last day. As a result, P. argentinus was considered an efficient predator of C. pipiens s.l. larvae under laboratory conditions.

Empirical studies of the EKC hypothesis may be very sensitive to datasets, specifications, and functional forms. The aim of this paper is to investigate the long-run relationship among CO2 emissions, real GDP, and energy consumption using a panel of 9 advanced economies from 1870 to 2008 using both parametric and semi-parametric additive models. While at the panel level the results provide support to the Environmental Kuznets Curve (EKC) only in the post-1950s period, at the individual country level the inverted U-shaped relationship between CO2 and real GDP is validated for a subset of countries only. However, when a semi-parametric regression framework is applied an inverse U-shaped pattern becomes clear for all countries of the sample, except Canada. Empirical findings indicate that relaxing the restrictions associated with parametric regression models may be critical for the question of investigating the existence of the EKC., JEL codes: C14; C23; Q43; Q32

Fil: Loretán, Gisela. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. Los eventos modeladores del paisaje que afectaron América del Sur desde el Mioceno hasta fechas recientes, determinaron la estructura actual de los ambientes acuáticos continentales, influenciando la dinámica y la evolución de las especies presentes. Los momentos y las circunstancias de la evolución de los decápodos de agua dulce han variado según el grupo en particular. La interrupción del flujo génico (aislamiento), producto de estos eventos geoclimáticos, sería una de las causas de la riqueza de los decápodos dulceacuícolas de determinadas familias, ya que presenta un escenario propicio para la especiación. El origen, distribución y diversificación de Aegla han sido y son motivo de discusión y las relaciones filogenéticas de sus especies han intrigado a los biólogos durante mucho tiempo. Los cangrejos de agua dulce de la familia Aeglidae tienen características que los convierten en un grupo muy adecuado para estudios evolutivos. Para esta tesis, se estudió mediante morfometría geométrica y marcadores moleculares, la filogeografía de dos especies (A. singularis y A. scamosa) y una población de Aegla sp. con caracteres diagnósticos compartidos con dos especies. El estudio de la filogeografía la familia Aeglidae demuestra que los eventos geoclimáticos que ocurridos en su área de distribución fueron una de las causas de su actual diversidad de especies. Sin embargo, la gran diversidad genética y variación morfológica que tienen estos cangrejos también fueron un elemento clave en la gran radiación y colonización de ambientes que marcaron la historia evolutiva de la familia. Landscape modeling events that affected South America from the Miocene to the present, determined the current structure of continental aquatic environments, influencing the dynamics and evolution of current species. Moments and circumstances of freshwater decapods evolution have varied according to the particular group. The gene flow interruption (isolation), product of these geoclimatic events, would be one of the causes of the freshwater decapods richness of certain families, since it presents a favorable scenario for speciation. The origin, distribution and diversification of Aegla have been and are the subject of discussion and the phylogenetic relationships of its species have intrigued biologists for a long time. For this thesis, the phylogeography of two species (A. singularis and A. scamosa) and a population of Aegla sp. with intermediate diagnostic characters, were studied. Phylogeography study of Aeglidae family shows that the geoclimatic events that occurred in its range were one of the causes of its current species diversity. However, the great genetic diversity and morphological variation that these crabs have were also a key element in the great radiation and environments colonization that marked the family evolutionary history. Consejo Nacional de Investigaciones Científicas y Técnicas Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación Ministerio de Educación de la Nación

Fil: Diawol, Valeria Paola. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. El objetivo de esta tesis fue estudiar ajustes biológicos y ecofisiológicos de los aéglidos que les permiten vivir y desarrollarse en ambientes con diferentes características abióticas. La distribución poblacional de los organismos analizados fue contagiosa, coincidiendo con el patrón conocido para otras especies de aéglidos. La reproducción se concentró en los meses más fríos del año, y los juveniles se liberaron en la siguiente temporada. Además, se observó variabilidad interespecífica, y se registraron diferentes patrones en términos de dinámica poblacional. Se observaron cambios en la forma del cefalotórax (alometría) durante la ontogenia de los individuos, además de variaciones en el tamaño. Los cambios en la forma del cefalotórax se relacionó distintas etapas del desarrollo ontogenético (juveniles y adultos) y con el dimorfismo sexual en adultos. El dimorfismo sexual se registró en la variación de la forma del cefalotórax y no en el tamaño. Se registró plasticidad fisiológica a lo largo de gradientes geográficos asociados con parámetros ambientales locales. Las tasas metabólicas, ensayadas bajo condiciones comunes de laboratorio, fueron similares entre las poblaciones y serían el resultado de la aclimatación de estos cangrejos a nuevos ambientes. Cuando se estudiaron diferentes especies, la hora del día (mediodía y atardecer), el peso corporal y el sexo afectaron el consumo de oxígeno de cada especie de diferentes maneras. Así, ante condiciones abióticas similares, cada especie presentaría un ajuste metabólico específico. Finalmente, se concluye que existen ajustes biológicos y ecofisiológicos de los aeglidos a los diferentes ambientes donde se distribuyen. The aim of this thesis was to study biological and ecophysiological adjustments of the aeglids, that allow them to live and develop in environments with different abiotic characteristics. Population distribution of organisms analyzed was clumped, coincident with the pattern known for other the aeglids species. Reproduction was concentrated in the coldest months of the year, and juveniles were released in the following season. In addition, interspecific variability was observed, and different patterns were recorded in terms of population dynamics. Allometry in the cephalothorax shape’s was registered during the ontogeny of the individuals, as well as variations in size. Shape variation in the cephalothorax were related to different stages of ontogenetic development (juveniles and adults) and to the sexual dimorphism in adults. Sexual dimorphism was recorded in cephalothorax shape variation and not in size. Physiological plasticity was registered along geographic gradients associated with local environmental parameters. Metabolic rates, tested under common laboratory conditions, were similar among the populations and would be the result of the acclimatization of these crabs to new environments. When we study different species, body weight and sex have an effect on oxygen consumption of each species in different ways. Thus, in the face of similar abiotic conditions, each species would present a specific metabolic adjustment. Finally, it is concluded that there are biological and ecophysiological adjustments of the aeglids to different environments where they lived. Consejo Nacional de Investigaciones Científicas y Técnicas