Browsing by Autor "Melina Campero"

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ANÁLISIS DE CORRESPONDENCIA CANONICA VS. REGRESION MUlTIPlE: ¿PUEDEN MOSTRAR DIFERENCIAS ENTRE HIDROECOREGIONES?
(2003) Melina Campero; Paul Van Damme; Boris Arévalo; Dora Claros
La regionalizacion de ambientes acuaticos es una herramienta ampliamente utilizada por su capacidad de simplificar diferentes estudios en zonas muy extensas o megadiversas, como es el caso de Bolivia. Sin embargo, son pocos los estudios o los metodos que demuestren que tales regionalizaciones son validas a nivel biologico y no herramientas ficticias creadas por el hombre. En este estudio, comparamos el uso del Analisis de Correspondecia Canonica y del Metodo de la Regresion multiple para determinar la capacidad de ambas herramientas para diferenciar tres subcuencas, situadas en diferentes hidroecoregiones en el Departamento de Cochabamba. El estudio se realizo sobre comunidades de macroinvertebrados bentonicos en tres cuencas: Alto Beni, Chapar e y Caine (sub cuencas al interior de la Cordillera Oriental). Las variables medioambientales fueron escogidas bajo criterios morfologicos y bioclimaticos, Yo sobre estas bases de datos, se aplicaron ambos analisis (CCA y regresion multiple). El CCA diferencio de mane.ra poco precisa las tres sub cuencas. Por otro lado, el metodo de la regresion multiple establecio diferencias numericas detectables entre las tres subcuencas, con la ventaja adicional de predecir de manera correcta la fauna al interior de la cuenca Alto Beni. Creemos que este metodo puede ser el mas efectivo al aplicarse, tanto en estudios de regionalizacion como de biomonitoreo. Palabras claves: Regionalizacion de ambientes acuaticos, regresion multiple, Analisis de Correspondencia Canonica, Bolivia. ABSTRACT Establishing ecoregions for aquatic environments is common because is simplifies studies in extents regions or were mega diversily exists, as is the case in Bolivia. Howevet; few studies have validated the method of delimitate ecoregions for biological studies. We compare the capacity of Canonical Correspondence Analysis and Multiple Regression to differentiate between three basins, located in different hydro-ecoregions in the State of Cochabamba. We studied macroinvertebrate communities from the Alto Beni, Chapare, and Caine basins (in the ecoregion of Andean Cordillera-Oriental Sector). The environmental variables were chosen based on bioclimatic and geomorpholgical Griteria. CCA and Multiple Regression were applied to both databases. The CCA did not differentiate the three basins clearlr Howevet; the Multiple Regression Method established significant differences between the three ba,sins and also predicted the fauna in Alto Beni basin. Thus, we conclude that Multiple Regression is more effective in identifying ecoregions and a more adequate tool for biomonitoring studies. Keywords: Establishment of ecoregions, Multiple Regression, Canonical Correspondence Analysis, Bolivia
Andean Lakes: a proposal for lake districts
(Taylor & Francis, 2024) Pablo Prado; Beatriz Modenutti; Nelson Aranguren-Riaño; Esteban Balseiro; Iris Samanez; Melina Campero; Carla E. Fernández; Carlos Rondón; Fernando M. Carvajal‐Vallejos; D. Mabel López-Paría
The Andes, the world’s longest mountain system (8500 km), harbour important headwater systems that constitute crucial water resources for South America. Their complex topography significantly influences climate and hydrology. The Andes have a wide diversity of aquatic environments, with >5000 lakes (>0.1 km2, permanent and excluding constructed reservoirs) with different morphometry, including the largest and the deepest in South America (Titicaca and Viedma, respectively). We applied a grouping analysis based on available systematised information to delimit different lake districts along the Andes. More than 60% of the surface area of all Andean lakes is concentrated in only 9 large lakes, and >80% of the lakes are <1 km2. This analysis proposes 11 lake districts, including 2 in the North Andes, 6 in the Central Andes, and 3 in the South Andes. Each lake district is described based on the different morphologies, geological origins, climatic factors, and available limnological information. We believe this study will benefit not only scientists but also decision-makers and stakeholders working in integrated water resource management in a region subject to climate change and socioeconomic inequalities.
Andean lakes: endangered by natural and anthropogenic threats
(Taylor & Francis, 2024) Melina Campero; Esteban Balseiro; Carla E. Fernández; Beatriz Modenutti; Pablo Prado; Carlos Rondón; Fernando M. Carvajal‐Vallejos; Yimy Herrera-Martínez; D. Mabel López-Paría; Nelson Aranguren-Riaño
The Andes mountains extend north–south in a latitudinal gradient of 8500 km. Because of the great climatic variety and the peculiar north–south orographic distribution, lakes are highly diverse, including different lake origins and contrasting morphometries. We reviewed >700 ecological studies on Andean lakes to identify the main threats to these freshwater systems. The most important threats are UV radiation, changes in water balance, and eutrophication, all 3 interacting with climate change, alien species introductions, and mining. UV radiation is an important factor in Andean lakes not only because of the altitude but also because many lakes are included in the Antarctic ozone hole. The introduction of alien species, particularly exotic salmonids, also had detrimental effects, affecting native fish populations and behaviour and endemic species by disrupting the indigenous food web. Eutrophication and browning caused by human activities, including land use interacting with climate change, are increasing in Andean lakes, causing a decrease in water quality. Finally, mining can cause water contamination (both groundwater and surface water) by chemicals emitted from mining processes, thus producing a loss of biodiversity. Although an important number of Andean lakes have been declared as Ramsar sites because of their uniqueness and their extreme conditions, they are subject to significant human impacts. Here, for the first time, we identify these impacts all along the Andes; however, further studies at different scales are mandatory if we hope to understand, conserve, and manage Andean lakes.
Context‐dependent resistance of freshwater invertebrate communities to drying
(Wiley, 2017) Thibault Datry; Ross Vander Vorste; Edgar Goïtia; Nabor Moya; Melina Campero; Fabiola Rodríguez; José Zubieta; Thierry Oberdorff
Abstract More freshwater ecosystems are drying in response to global change thereby posing serious threat to freshwater biota and functions. The production of desiccation‐resistant forms is an important adaptation that helps maintain biodiversity in temporary freshwaters by buffering communities from drying, but its potential to mitigate the negative effects of drying in freshwater ecosystems could vary greatly across regions and ecosystem types. We explored this context dependency by quantifying the potential contribution of desiccation‐resistance forms to invertebrate community recovery across levels of regional drying prevalence (defined as the occurrence of drying events in freshwaters in a given region) and ecosystem types (lentic, lotic) in temporary neotropical freshwaters. We first predicted that regional drying prevalence influences the selection of species with desiccation‐resistant forms from the regional species pools and thus increases the ability of communities to recover from drying. Second, we predicted lentic freshwaters harbor higher proportions of species with desiccation‐resistant forms compared to lotic, in response to contrasted hydrologic connectivity. To test these predictions, we used natural experiments to quantify the contribution of desiccation‐resistant forms to benthic invertebrate community recovery in nine intermittent streams and six geographically isolated temporary wetlands from three Bolivian regions differing in drying prevalence. The contribution of desiccation‐resistant forms to community recovery was highest where regional drying prevalence was high, suggesting the species pool was adapted to regional disturbance regimes. The contribution of desiccation‐resistant forms to community recovery was lower in streams than in wetlands, emphasizing the importance of hydrologic connectivity and associated recolonization processes from in‐stream refuges to recovery in lotic systems. In all regions, the majority of functional traits were present in desiccation‐resistant taxa indicating this adaptation may help maintain ecosystem functions by buffering communities from the loss of functional traits. Accounting for regional context and hydrologic connectivity in community recovery processes following drying can help refine predictions of freshwater biodiversity response to global change.
Correcting the short‐term effect of food deprivation in a damselfly: mechanisms and costs
(Wiley, 2007) Melina Campero; Marjan De Block; F. Ollevier; Robby Stoks
1. Mass at emergence is a life-history trait strongly linked to adult fitness. Therefore, when faced with transient food shortage in the larval stage, mass-correcting mechanisms are common. 2. These correcting mechanisms may carry costs with them. On one hand, these costs may be overestimated because they can be confounded with the direct effects of the transient food shortage itself. On the other hand, costs may be underestimated by ignoring physiological costs. Another largely neglected topic is that correcting mechanisms and costs may critically depend upon other stressors that often co-occur. 3. Here, we identify the mass-correcting mechanisms and their associated costs at emergence in the damselfly Coenagrion puella, after being stressed by a transient period of starvation and a subsequent exposure to pesticide stress during the larval stage. We introduce path analysis to disentangle direct costs of starvation and the mass-correcting mechanisms in terms of immune response. 4. As predicted, we found no differences in mass at emergence. Starvation directly resulted in a costly delayed emergence and a decreased immune response at emergence. Mass-correcting mechanisms included a prolonged post-starvation period, reduced mass loss at emergence and compensatory growth, although the latter only in females under pesticide stress. 5. The mass-correcting mechanisms were associated with beneficial effects on investment in immune response, but only in the absence of pesticide stress. Under pesticide stress, these beneficial effects were mostly undone or overruled, resulting in negative effects of the mass-correcting mechanisms in terms of immune response. 6. Our results stress the importance of and introduce a statistical way of disentangling direct costs of starvation and the mass-correcting mechanisms themselves, and the importance of including physiological endpoints in this kind of studies.
Disentangling population strategies of two cladocerans adapted to different ultraviolet regimes
(Wiley, 2018) Carla E. Fernández; Melina Campero; Cíntia Bertacchi Uvo; Lars‐Anders Hansson
Zooplankton have evolved several mechanisms to deal with environmental threats, such as ultraviolet radiation (UVR), and in order to identify strategies inherent to organisms exposed to different UVR environments, we here examine life-history traits of two lineages of Daphnia pulex. The lineages differed in the UVR dose they had received at their place of origin from extremely high UVR stress at high-altitude Bolivian lakes to low UVR stress near the sea level in temperate Sweden. Nine life-history variables of each lineage were analyzed in laboratory experiments in the presence and the absence of sub-lethal doses of UVR (UV-A band), and we identified trade-offs among variables through structural equation modeling (SEM). The UVR treatment was detrimental to almost all life-history variables of both lineages; however, the Daphnia historically exposed to higher doses of UVR (HighUV) showed a higher overall fecundity than those historically exposed to lower doses of UVR (LowUV). The total offspring and ephippia production, as well as the number of clutches and number of offspring at first reproduction, was directly affected by UVR in both lineages. Main differences between lineages involved indirect effects that affected offspring production as the age at first reproduction. We here show that organisms within the same species have developed different strategies as responses to UVR, although no increased physiological tolerance or plasticity was shown by the HighUV lineage. In addition to known tolerance strategies to UVR, including avoidance, prevention, or repairing of damages, we here propose a population strategy that includes early reproduction and high fertility, which we show compensated for the fitness loss imposed by UVR stress.
Disentangling Population Strategies of Two Cladocerans Adapted to Different Ultraviolet Regimes
(RELX Group (Netherlands), 2018) Carla Fernandez Espinoza; Melina Campero; Cíntia Bertacchi Uvo; Lars‐Anders Hansson
Zooplankton have evolved several mechanisms to deal with environmental threats, such as ultraviolet radiation (UVR), and in order to identify strategies inherent to organisms exposed to different UVR environments, we here examine life-history traits of two lineages of Daphnia pulex. The lineages differed in the UVR dose they had received at their place of origin from extremely high UVR stress at high-altitude Bolivian lakes to low UVR stress near the sea level in temperate Sweden. Nine life-history variables of each lineage were analyzed in laboratory experiments in the presence and the absence of sub-lethal doses of UVR (UV-A band), and we identified trade-offs among variables through structural equation modeling (SEM). The UVR treatment was detrimental to almost all life-history variables of both lineages; however, the Daphnia historically exposed to higher doses of UVR (HighUV) showed a higher overall fecundity than those historically exposed to lower doses of UVR (LowUV). The total offspring and ephippia production, as well as the number of clutches and number of offspring at first reproduction, was directly affected by UVR in both lineages. Main differences between lineages involved indirect effects that affected offspring production as the age at first reproduction. We here show that organisms within the same species have developed different strategies as responses to UVR, although no increased physiological tolerance or plasticity was shown by the HighUV lineage. In addition to known tolerance strategies to UVR, including avoidance, prevention, or repairing of damages, we here propose a population strategy that includes early reproduction and high fertility, which we show compensated for the fitness loss imposed by UVR stress.
Diversity of Rotifera in Freshwaters of Bolivia: An Updated Checklist
(Multidisciplinary Digital Publishing Institute, 2024) Carla E. Fernández; Melina Campero; Francisca Acosta; Pablo Prado; Mabel Maldonado; Edgar Goïtia; Georgia Stamou; Εvangelia Μichaloudi; Carlos López
Biodiversity records are of great importance, especially in light of the biodiversity crisis. Here, we present a study on the diversity of rotifers in Bolivia based on an extensive investigation of the literature published so far. Through this approach and an analysis of samples from 207 water bodies of the country, we updated the checklist of reported species. This study revealed a total of 195 species of rotifers previously reported; we identified 153 species in our samples, with 84 of them being reported for the first time in Bolivia. Thus, a total of 279 species are known at present in this country. Our findings suggest that Bolivia has a rich and diverse rotifer community, with many species likely to be unique to the region.
Ecological relevance and sensitivity depending on the exposure time for two biomarkers
(Wiley, 2007) Melina Campero; F. Ollevier; Robby Stoks
Biomarkers are widely used to assess pesticide stress, but their ecological relevance and exposure time dependent sensitivity is still heavily debated. We studied both aspects in larvae of the damselfly Coenagrion puella, comparing the impact of low doses of atrazine, carbaryl, and endosulfan on two key biomarkers (acetylcholinesterase [AChE] activity and fluctuating asymmetry [FA]) and their relationship with life history traits (mortality, development time, growth rate, and body size). Larvae exposed to the pesticides had, in general, longer development times. Size, growth rate, and mortality were not affected by any of the pesticides. In the long-term exposure, AChE activity was diminished by atrazine treatments and stimulated by carbaryl treatments, and was not affected in the endosulfan treatments. FA decreased with increasing endosulfan concentrations and showed no reaction to atrazine or carbaryl. Overall, short-term exposure tended to overestimate the results of long-term exposure decreasing growth rates and enhancing inhibition of AChE activity in atrazine and carbaryl treatments. In line with its ecological relevance, relationship between biomarkers and life history traits showed that AChE inhibition was positively correlated with mortality, while FA was traded off with size. These results show that caution should be exerted when using these biomarkers to assess pesticide pollution in field situations.
Latitudinal and voltinism compensation shape thermal reaction norms for growth rate
(Wiley, 2011) Lisa N. S. Shama; Melina Campero; K. Mathias Wegner; Marjan De Block; Robby Stoks
Latitudinal variation in thermal reaction norms of key fitness traits may inform about the response of populations to climate warming, yet their adaptive nature and evolutionary potential are poorly known. We assessed the contribution of quantitative genetic, neutral genetic and environmental effects to thermal reaction norms of growth rate for populations of the damselfly Ischnura elegans. Among populations, reaction norms differed primarily in elevation, suggesting that time constraints associated with shorter growth seasons in univoltine, high-latitude as well as multivoltine, low-latitude populations selected for faster growth rates. Phenotypic divergence among populations is consistent with selection rather than drift as Q(ST) was greater than F(ST) in all cases. Q(ST) estimates increased with experimental temperature and were influenced by genotype by environment interactions. Substantial additive genetic variation for growth rate in all populations suggests that evolution of trait means in different environments is not constrained. Heritability of growth rates was higher at high temperature, driven by increased genetic rather than environmental variance. While environment-specific nonadditive effects also may contribute to heritability differences among temperatures, maternal effects did not play a significant role (where these could be accounted for). Genotype by environment interactions strongly influenced the adaptive potential of populations, and our results suggest the potential for microevolution of thermal reaction norms in each of the studied populations. In summary, the observed latitudinal pattern in growth rates is adaptive and results from a combination of latitudinal and voltinism compensation. Combined with the evolutionary potential of thermal reaction norms, this may affect populations' ability to respond to future climate warming.
Local adaptation to <scp>UV</scp> radiation in zooplankton: a behavioral and physiological approach
(Wiley, 2020) Carla E. Fernández; Melina Campero; Giuseppe Bianco; Mikael T. Ekvall; Danny Rejas; Cíntia Bertacchi Uvo; Lars‐Anders Hansson
Abstract Ultraviolet radiation ( UVR ) is recognized as a driving force for phenotypic divergence. Here, we aim at assessing the ability of zooplankton to induce UVR tolerance and disentangle the relative importance of local adaptations behind the expression of such tolerance. Two populations of Daphnia pulex, derived from environments strongly differing in UVR conditions, were exposed to UVR for 70 d to induce production of photo‐protective compounds and changes in behavioral responses. We expected greater tolerance to UVR in individuals from the high‐ UVR (H‐U) environment as well as a refuge demand inversely related to the level of pigmentation. However, the complementarity between physiological and behavioral strategies was only observed on animals from the Low‐ UVR environment (L‐U). L‐U animals developed photo‐protective compounds and decreased their refuge demand when re‐exposed to UVR , that is, tolerated more UVR , compared to their control siblings. Conversely, UVR ‐exposed individuals from the H‐U environment even having developed higher levels of photo‐protective compounds increased their refuge demand staying deeper in the water column compared to the control animals, likely expressing an evolutionary memory to seek refuge in deeper waters irrespective of the UVR level. Stronger changes were observed in the H‐U population compared to the L‐U population; thus, our results suggest that although changes in tolerance after UVR exposure were evident for both populations, the strength of the inductions was more related to local adaptation independently of the rearing environment, showing that UVR tolerance is dependent on the evolutionary history of each population.
Metamorphosis offsets the link between larval stress, adult asymmetry and individual quality
(Wiley, 2008) Melina Campero; Marjan De Block; F. Ollevier; Robby Stoks
1 It is poorly understood which traits translate larval stressors into adult fitness in animals where larval and adult stages are separated by metamorphosis. Although fluctuating asymmetry (FA) is often assumed to do so, especially in insects the relationship between larval stress, adult FA and individual quality is often absent. One suggested hypothesis for this is the higher mortality of low quality (hence more asymmetric) animals during metamorphosis (i.e. developmental selection hypothesis). 2 Here we test this hypothesis and also propose and test an alternative hypothesis where metamorphosis is stressful but not lethal and increases FA of all animals up to a certain level (i.e. stressful metamorphosis hypothesis). 3 We manipulated larval stress (food stress and pesticide stress) and measured FA before and after metamorphosis in the damselfly Coenagrion puella. Additionally, we assessed the relationship between FA and individual quality variables measured at metamorphosis (age, mass and two immune variables: phenoloxidase (PO) and haemocyte number). 4 Before metamorphosis, FA reflected the combination of food and pesticide stress and was negatively related with mass and both immune variables after metamorphosis. These patterns were, however, offset after metamorphosis. Low mortality, not linked to FA during metamorphosis, indicates that developmental selection cannot explain this. Instead, the strong increase in FA up to equal levels across treatments during metamorphosis supports the stressful metamorphosis hypothesis. 5 Taken together, the developmental stage in which FA is measured may critically determine the reliability of FA as an indicator of stress and of individual quality in insects.
Opinion Paper: how vulnerable are Amazonian freshwater fishes to ongoing climate change?
(Wiley, 2015) Thierry Oberdorff; Céline Jezequel; Melina Campero; Fernando M. Carvajal‐Vallejos; J. F. Cornu; Murilo S. Dias; Fabrice Duponchelle; Javier A. Maldonado‐Ocampo; Hernán Ortega; Jean‐François Renno
With around 15% of all described freshwater fish species in the world, the Amazon Basin is by far the most fish species-rich freshwater ecosystem on the planet. In this opinion paper, a rough evaluation is given on just how vulnerable Amazonian freshwater fishes are to ongoing climate change. And to argue that current anthropogenic threats through rapid expansion of human infrastructure and economic activities in the basin could be a far greater threat to fish communities than those anticipated by any future climate change. Conservation actions in the Amazon Basin should focus preferentially on reducing the impacts of present-day anthropogenic threats.
SUBLETHAL PESTICIDE CONCENTRATIONS AND PREDATION JOINTLY SHAPE LIFE HISTORY: BEHAVIORAL AND PHYSIOLOGICAL MECHANISMS
(Wiley, 2007) Melina Campero; Stefanie Slos; F. Ollevier; Robby Stoks
Despite their relevance for risk assessment, the interactive effects of pesticide and predation cues are poorly understood because the underlying behavioral and physiological mechanisms are largely unknown. To explore these mechanisms, we reared larvae of the damselfly Coenagrion puella at three different predation risk levels and a range of environmentally realistic concentrations of three pesticides used worldwide (atrazine, carbaryl, and endosulfan). We compared key development responses (growth rate, developmental time, and final size) against food ingestion, assimilation, and conversion efficiency, and acetylcholinesterase (AChE) activity. Predation risk impaired all endpoints, including AChE activity, while the effects of pesticide stress were smaller for atrazine and endosulfan and absent for carbaryl. The effects of both stressors and their interaction on life history were mostly indirect through resource acquisition and energy allocation. Compensatory physiological mechanisms to pesticide stress (atrazine and endosulfan) were present in larvae reared in the absence of predation stress but were offset under predation stress. As a result, smaller size (atrazine and endosulfan) and lower growth rate (endosulfan) from pesticide stress were only found in the highest predation risk treatment. Our results provide insight as to the conditions under which interactions between stressors are likely to occur: damselfly populations at high density and living in fish ponds will be more affected by pesticides than populations at low densities in fishless ponds. By identifying variables that may shape the interaction between predation stress and other stressors such as pesticides, our mechanistic approach may help to bridge the gap between laboratory and field studies.
Temperature and ultraviolet radiation on a high mountain daphnid: When do interactions become lethal to highly adapted populations?
(Taylor & Francis, 2024) Daniel Nino Flores-Mendez; Carla E. Fernández; Melina Campero
Aquatic organisms from high mountain lakes experience extreme influences of climate and solar radiation, especially ultraviolet radiation (UVR), manifested through alterations in physiology, life history, and phenology. Zooplankton, a pivotal component of lake ecosystems, is particularly sensitive to changes in environmental conditions because of their short life cycles and diminished mobility. In the high mountains of the tropical Andes, zooplankton populations are adapted to low temperatures and high UVR because most of the Andean lakes are >4000 m a.s.l. This study focuses on Daphnia pulicaria populations originating from high-mountain Andean lakes, investigating their responses to different temperatures and UVR exposure by means of lab experiments. Key findings indicate that temperature is the most important factor impacting population variables, with high temperatures and UVR exposure leading to unfavorable population outcomes; however, physiological variables (cell viability and pigmentation, measured as melanin) are similarly influenced by temperature and UVR exposure. Pigmentation increases with temperature and is accentuated by solar radiation, indicating an adaptive response to mitigate UVR damage. Conversely, cellular viability declines with elevated temperatures and UVR exposure, showing that higher temperatures may offset the protective effects of pigmentation. Overall, these findings underscore the vulnerability of daphnid populations in high-mountain Andean systems to anticipated climate change impacts, with potential consequences for ecological dynamics in these critical ecosystems. More importantly, they show the importance of studying temperature and UVR (and probably other environmental conditions) as interacting variables because the results will dramatically differ if each factor is considered separately.
The microbiome of a polluted urban lake harbors pathogens with diverse antimicrobial resistance and virulence genes
(Elsevier BV, 2021) Jorge Quillaguamán; Daniel Guzmán; Melina Campero; C. Hoepfner; Laura Relos; Daniela Mendieta; Shawn M. Higdon; Daniel Eid Rodríguez; Carla E. Fernández
Weight‐Length Ratio of Piranhas Serrasalmus (Characiformes, Serrasalmidae) in Bolivia: Relationships to Molecular Divergence and Maximum Size?
(Wiley, 2025) Fernando M. Carvajal‐Vallejos; F. Gallo-Cardozo; M. Careaga; Melina Campero
Weight-Length Relationships (WLRs) provide a basis for comparing life history strategies and morphological differentiation among fish species, potentially linking slope variations to evolutionary divergences in size and weight. This study presents the WLRs of nine Serrasalmus piranha species from the Amazon and La Plata basins in Bolivia, assessing whether WLRs slopes are influenced by phylogenetic relationships using a phylogenetic mixed model analysis on the mitochondrial DNA COI (barcoding) locus. All species demonstrated an exponential (power-type) growth pattern, with most showing positive allometric growth. The species showing the greatest differentiation in both WLRs and genetic variation was S. elongatus. We detected a strong phylogenetic signal in WLR slopes, though clustering techniques for WLRs slopes and molecular data revealed only partial concordance. We discuss how these concordances and discrepancies between WLRs and genetic data may reflect ancient and intermediate speciation events, shaped by habitat conditions and stochastic evolutionary processes. Such processes appear to influence swimming mechanisms and ecological niche navigation in these closely related Serrasalmus species.