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Susana Caballero - One of the best experts on this subject based on the ideXlab platform.
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Initial description of Major Histocompatibility Complex variation at two Class II loci (DQA-DQB) in Sotalia fluviatilis and Sotalia guianensis
Latin American Journal of Aquatic Mammals, 2010Co-Authors: Susana Caballero, Fernando Trujillo, Juliana A. Vianna, Héctor Barrios-garrido, M. G. Montiel, Sandra Beltran-pedreros, Miriam Marmontel, Marcos César De Oliveira Santos, D. Heimeier, Marcos R. Rossi-santosAbstract:Genes of the major histocompatibility complex (MHC) play a key role in the initiation of immune response in jawed vertebrates. Variation at MHC loci can be used as an indicator of the genetic ‘health’ of natural populations and offer insight into potential susceptibility to epizootics. Here we present the first characterization of the sequence variation at two MHC class II loci (DQA and DQB) in the neotropical coastal ( Sotalia guianensis ) and riverine ( Sotalia fluviatilis ) dolphins, using cloning and direct sequencing of amplified genomic DNA. Four DQA and four DQB alleles were identified in 33 and 32 Sotalia samples, respectively, and high nucleotide diversity among these alleles was detected, similar to the findings described for other cetacean species. Positive selection was evidenced by an excess of d n /d s at the Peptide-Binding-Region of the DQB of Sotalia . The presence of common alleles at both loci in S. fluviatilis and S. guianensis are consistent with trans-species mode of evolution in the MHC. In contrast to observed low levels of mtDNA diversity at the population level, there was an apparent lack of reduction of DQA and DQB allelic variation in the Brazilian Coast population unit. This suggests either present or past balancing selection acting to maintain MHC variation in this population unit.
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MITOCHONDRIAL DNA DIVERSITY, DIFFERENTIATION AND PHYLOGEOGRAPHY OF THE SOUTH AMERICAN RIVERINE AND COASTAL DOLPHINS Sotalia FLUVIATILIS AND Sotalia GUIANENSIS
Latin American Journal of Aquatic Mammals, 2010Co-Authors: Susana Caballero, Fernando Trujillo, Juliana A. Vianna, Héctor Barrios-garrido, Sandra Beltran-pedreros, Miriam Marmontel, Maria G. Montiel, O. Santos, Marcos R. Rossi-santosAbstract:Here we consider the phylogeography and population structure of the South American coastal and riverine dolphins, Sotalia guianensis and Sotalia fluviatilis, based on samples (n = 76) collected across more than 9000km of the species distribution. Phylogenetic reconstruction of 31 distinct haplotypes based on a combined analysis of two mitochondrial gene fragments (1052bp) revealed clear genetic differences between riverine and coastal individuals consistent with species-level ranking. Within the coastal species, a spatial analysis of molecular variance of the control region sequences showed significant regional population differentiation (FST = 0.4; FST = 0.6; P
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A Tale of Two Dolphins: Introduction to the Special Volume on the Biology and Conservation of Neotropical Dolphins of the Genus Sotalia
Latin American Journal of Aquatic Mammals, 2010Co-Authors: Marcos César De Oliveira Santos, Salvatore Siciliano, Susana Caballero, C. Olavarría, M. Borobia, Eduardo R. Secchi, Daniel M. PalaciosAbstract:A Tale of Two Dolphins: Introduction to the Special Volume on the Biology and Conservation of Neotropical Dolphins of the Genus Sotalia
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mitochondrial dna diversity differentiation and phylogeography of the south american riverine and coastal dolphins Sotalia fluviatilis and Sotalia guianensis
Latin American Journal of Aquatic Mammals, 2010Co-Authors: Susana Caballero, Fernando Trujillo, Juliana A. Vianna, Miriam Marmontel, Maria G. Montiel, O. Santos, Hector Barriosgarrido, Sandra Beltranpedreros, Marcos R Rossisantos, Fabrício R. SantosAbstract:Here we consider the phylogeography and population structure of the South American coastal and riverine dolphins, Sotalia guianensis and Sotalia fluviatilis, based on samples (n = 76) collected across more than 9000km of the species distribution. Phylogenetic reconstruction of 31 distinct haplotypes based on a combined analysis of two mitochondrial gene fragments (1052bp) revealed clear genetic differences between riverine and coastal individuals consistent with species-level ranking. Within the coastal species, a spatial analysis of molecular variance of the control region sequences showed significant regional population differentiation (FST = 0.4; FST = 0.6; P<0.001). The highest mitochondrial diversity among costal population units was found along the Caribbean Coast of Colombia and Venezuela. The genetic distinctiveness of the Maracaibo Lake (Venezuela) population has conservation implications regarding the threats faced by the animals in this region, including oil exploitation. Brazilian populations of Sotalia showed the lowest mitochondrial diversity and differentiation among the coastal species warranting further investigation. The Amazonian populations showed the highest mitochondrial diversity overall, suggesting a surprisingly large effective population size (Nef) and relatively high female gene flow throughout the sampled regions of the main river and its tributaries. From our results, at least two different conservation strategies need to be developed for each of the proposed sister-species. For the coastal groups, characterized by restricted gene flow and very localized populations along the Caribbean and Atlantic Coast of South America, it is advisable to work at a local level in order to improve the fishing practices and prevent frequent dolphin entanglement in nets. For the Amazonian groups, priority must be given to maintain the connectivity detected between regions. Obstacles to connectivity, including hydroelectric and dam construction, as well as excessive boat traffic, could affect the future of these populations. RESUMEN: En este trabajo consideramos aspectos filogeograficos y estructura poblacional de los delfines Sudamericanos Sotalia guianensis
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Molecular systematics of South American dolphins Sotalia: Sister taxa determination and phylogenetic relationships, with insights into a multi-locus phylogeny of the Delphinidae
Molecular phylogenetics and evolution, 2007Co-Authors: Susana Caballero, Héctor Barrios-garrido, Sandra Beltran-pedreros, Jennifer A. Jackson, Antonio A. Mignucci-giannoni, Marı´a G. Montiel-villalobos, Kelly M. Robertson, C. Scott BakerAbstract:The evolutionary relationships among members of the cetacean family Delphinidae, the dolphins, pilot whales and killer whales, are still not well understood. The genus Sotalia (coastal and riverine South American dolphins) is currently considered a member of the Stenoninae subfamily, along with the genera Steno (rough toothed dolphin) and Sousa (humpbacked dolphin). In recent years, a revision of this classification was proposed based on phylogenetic analysis of the mitochondrial gene cytochrome b, wherein Sousa was included in the Delphininae subfamily, keeping only Steno and Sotalia as members of the Stenoninae subfamily. Here we investigate the phylogenetic placement of Sotalia using two mitochondrial genes, six autosomal introns and four Y chromosome introns, providing a total of 5,196 base pairs (bp) for each taxon in the combined dataset. Sequences from these genomic regions were obtained for 17 delphinid species, including at least one species from each of five or six currently recognized subfamilies plus five odontocete outgroup species. Maximum Parsimony, Maximum Likelihood and Bayesian phylogenetic analysis of independent (each fragment) and combined datasets (mtDNA, nuDNA or mtDNA+nuDNA) showed that Sotalia and Sousa fall within a clade containing other members of Delphininae, exclusive of Steno. Sousa was resolved as the sister taxon to Sotalia according to analysis of the nuDNA dataset but not analysis of the mtDNA or combined mtDNA+nuDNA datasets. Based on the results from our multi-locus analysis, we offer several novel changes to the classification of Delphinidae, some of which are supported by previous morphological and molecular studies.
Fernando Trujillo - One of the best experts on this subject based on the ideXlab platform.
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tamano poblacional densidad y distribucion de inia geoffrensis y Sotalia fluviatilis en la cuenca media del rio caqueta
Momentos de Ciencia, 2015Co-Authors: Fernando Trujillo, Hugo Mantilla Meluk, Alexander Velasquez Valencia, Diego Ruiz H Valderrama, Antonio Villa F Navarro, Gabriel Albornoz J Garzon, Isis LondonoAbstract:Investigadores de la Fundacion Omacha, Universidades Quindio, Tolima, Amazonia y Parques Nacionales Naturales, realizaron entre los dias 3 al 11 de julio, la expedicion al rio Caqueta y tributarios como: Yari, Miriti, Meta, Cahunari y canos Solarte y San Francisco. Los objetivos de la investigacion fue realizar la estimacion de densidades y tamano poblacional para los delfines de rio Inia geoffrensis y Sotalia fluviatilis en la cuenca media del rio Caqueta en los tipos de habitat Rio Principal, Confluencias, Canal e Isla. Se caracterizaron las principales amenazas para su conservacion identificando a la mineria ilegal, deforestacion y uso de redes de pesca como los principales tensores para la conservacion de estas especies. Se evaluo un tramo 625 km-1 comprendidos entre las localidades de Araracuara (Caqueta) y La Pedrera (Amazonas) en Colombia, registrando 126 observaciones en ambas plataformas (I geoffrensis: 99 (78,5%); S fluviatilis: 27 (21,5%), contabilizando 242 individuos (I geoffrensis: 165 (68,2%); S fluviatilis: 77 (31,8%). Las mayores densidades registradas correspondieron para Inia geoffrensis en el tipo de habitat Confluencia con el rio Cahunari 8,23 Inia/Km2 (CV(dp)=1,35). En relacion a Sotalia fluviatilis para el tipo de habitat Rio Principal 2,6 Sotalia/Km2 (CV(dp)=0,43). Los resultados obtenidos indican que la densidad de Inia geoffrensis fue mayor que Sotalia fluviatilis, cuyos individuos ocurren despues del rapido de Cordoba que actua como una barrera geografica para la especie. Esta investigacion se enmarca dentro del programa para la estimacion de abundancia, identificacion de amenazas y distribucion de los delfines de rio auspiciado por Nature Serve.
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distribucion y tamano poblacional de inia geoffrensis y Sotalia fluviatilis en los rios javari y loretoyacu
Momentos de Ciencia, 2015Co-Authors: Tatiana Riveros Castro, Fernando Trujillo, Hugo Mantilla Meluk, Eric Ortega Chacon, Federico GuerraAbstract:Esta investigacion hace parte de la estrategia de articulacion entre la Reserva Natural Palmari (Brasil), Fundacion Omacha y Universidad Francisco Jose de Caldas (Colombia) en aras de generar escenarios de conservacion a traves de la construccion de conocimiento en aspectos como: distribucion y tamanos poblacionales de Inia geoffrensis y Sotalia fluviatilis en los rios Javari y Loretoyacu, tributarios del rio Amazonas en la trifrontera entre Colombia, Brasil y Peru. Este estudio fue realizado durante el ano 2013 en los periodos hidrologico de aguas altas (marzo) y aguas descendentes (junio). Las areas de estudio fueron los sistemas hidrologicos ubicados en la Reserva Natural Palmari (Brasil) y Puerto Narino (Colombia). El tamano poblacional para los delfines de rio fue establecido a traves de la metodologia propuesta por Gomez et al (2011); se aplicaron 60 transectos entre lineales y en banda, navegando 180 km-1 en las areas de estudio. Los mayores valores obtenidos para la densidad de Inia geoffrensis se presento en el rio Javari en el tipo de habitat tributario aportando D= 2,3 Inia/Km2 y las densidades mas altas para Sotalia fluviatilis se presentaron en el rio Javari en el tipo de habitat tributario D= 3,4 Sotalia/Km2. En relacion a los tamanos poblacionales en los dos sistemas evaluados se registro un mayor numero de individuos en el rio Javari donde la especie Sotalia fluviatilis aporto las mayores abundancias observandose un posible solapamiento de nicho entre estas dos especies de cetaceos que presentan distribucion simpatrica.
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Population, density estimates, and conservation of river dolphins (Inia and Sotalia) in the Amazon and Orinoco river basins
Marine Mammal Science, 2011Co-Authors: Catalina Gomez-salazar, Fernando Trujillo, Nova Scotia, Marcela Portocarrero-ayaAbstract:This study is part of an on-going effort to evaluate and monitor river dolphin populations in South America. It comprises the largest initiative to estimate population size and densities of Inia and Sotalia dolphins using statistically robust and standardized methods. From May 2006 to August 2007, seven visual surveys were conducted in selected large rivers of Bolivia, Colombia, Brazil, Ecuador, Peru, and Venezuela in the Amazon and Orinoco river basins. Population sizes of Inia and Sotalia were estimated for different habitats (main river, tributary, lake, island, confluence, and channel). A total of 291 line and 890 strip transects were conducted, covering a distance of 2,704 linear kilometers. We observed 778 Inia geoffrensis, 1,323 Inia boliviensis, and 764 Sotalia fluviatilis. High-density areas were identified (within 200 m from the river banks, confluences, and lakes) and we propose that these constitute critical habitat for river dolphins. High densities of river
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Initial description of Major Histocompatibility Complex variation at two Class II loci (DQA-DQB) in Sotalia fluviatilis and Sotalia guianensis
Latin American Journal of Aquatic Mammals, 2010Co-Authors: Susana Caballero, Fernando Trujillo, Juliana A. Vianna, Héctor Barrios-garrido, M. G. Montiel, Sandra Beltran-pedreros, Miriam Marmontel, Marcos César De Oliveira Santos, D. Heimeier, Marcos R. Rossi-santosAbstract:Genes of the major histocompatibility complex (MHC) play a key role in the initiation of immune response in jawed vertebrates. Variation at MHC loci can be used as an indicator of the genetic ‘health’ of natural populations and offer insight into potential susceptibility to epizootics. Here we present the first characterization of the sequence variation at two MHC class II loci (DQA and DQB) in the neotropical coastal ( Sotalia guianensis ) and riverine ( Sotalia fluviatilis ) dolphins, using cloning and direct sequencing of amplified genomic DNA. Four DQA and four DQB alleles were identified in 33 and 32 Sotalia samples, respectively, and high nucleotide diversity among these alleles was detected, similar to the findings described for other cetacean species. Positive selection was evidenced by an excess of d n /d s at the Peptide-Binding-Region of the DQB of Sotalia . The presence of common alleles at both loci in S. fluviatilis and S. guianensis are consistent with trans-species mode of evolution in the MHC. In contrast to observed low levels of mtDNA diversity at the population level, there was an apparent lack of reduction of DQA and DQB allelic variation in the Brazilian Coast population unit. This suggests either present or past balancing selection acting to maintain MHC variation in this population unit.
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MITOCHONDRIAL DNA DIVERSITY, DIFFERENTIATION AND PHYLOGEOGRAPHY OF THE SOUTH AMERICAN RIVERINE AND COASTAL DOLPHINS Sotalia FLUVIATILIS AND Sotalia GUIANENSIS
Latin American Journal of Aquatic Mammals, 2010Co-Authors: Susana Caballero, Fernando Trujillo, Juliana A. Vianna, Héctor Barrios-garrido, Sandra Beltran-pedreros, Miriam Marmontel, Maria G. Montiel, O. Santos, Marcos R. Rossi-santosAbstract:Here we consider the phylogeography and population structure of the South American coastal and riverine dolphins, Sotalia guianensis and Sotalia fluviatilis, based on samples (n = 76) collected across more than 9000km of the species distribution. Phylogenetic reconstruction of 31 distinct haplotypes based on a combined analysis of two mitochondrial gene fragments (1052bp) revealed clear genetic differences between riverine and coastal individuals consistent with species-level ranking. Within the coastal species, a spatial analysis of molecular variance of the control region sequences showed significant regional population differentiation (FST = 0.4; FST = 0.6; P
Fabrício R. Santos - One of the best experts on this subject based on the ideXlab platform.
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mitochondrial dna diversity differentiation and phylogeography of the south american riverine and coastal dolphins Sotalia fluviatilis and Sotalia guianensis
Latin American Journal of Aquatic Mammals, 2010Co-Authors: Susana Caballero, Fernando Trujillo, Juliana A. Vianna, Miriam Marmontel, Maria G. Montiel, O. Santos, Hector Barriosgarrido, Sandra Beltranpedreros, Marcos R Rossisantos, Fabrício R. SantosAbstract:Here we consider the phylogeography and population structure of the South American coastal and riverine dolphins, Sotalia guianensis and Sotalia fluviatilis, based on samples (n = 76) collected across more than 9000km of the species distribution. Phylogenetic reconstruction of 31 distinct haplotypes based on a combined analysis of two mitochondrial gene fragments (1052bp) revealed clear genetic differences between riverine and coastal individuals consistent with species-level ranking. Within the coastal species, a spatial analysis of molecular variance of the control region sequences showed significant regional population differentiation (FST = 0.4; FST = 0.6; P<0.001). The highest mitochondrial diversity among costal population units was found along the Caribbean Coast of Colombia and Venezuela. The genetic distinctiveness of the Maracaibo Lake (Venezuela) population has conservation implications regarding the threats faced by the animals in this region, including oil exploitation. Brazilian populations of Sotalia showed the lowest mitochondrial diversity and differentiation among the coastal species warranting further investigation. The Amazonian populations showed the highest mitochondrial diversity overall, suggesting a surprisingly large effective population size (Nef) and relatively high female gene flow throughout the sampled regions of the main river and its tributaries. From our results, at least two different conservation strategies need to be developed for each of the proposed sister-species. For the coastal groups, characterized by restricted gene flow and very localized populations along the Caribbean and Atlantic Coast of South America, it is advisable to work at a local level in order to improve the fishing practices and prevent frequent dolphin entanglement in nets. For the Amazonian groups, priority must be given to maintain the connectivity detected between regions. Obstacles to connectivity, including hydroelectric and dam construction, as well as excessive boat traffic, could affect the future of these populations. RESUMEN: En este trabajo consideramos aspectos filogeograficos y estructura poblacional de los delfines Sudamericanos Sotalia guianensis
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TAXONOMIC STATUS OF THE GENUS Sotalia: SPECIES LEVEL RANKING FOR “TUCUXI” (Sotalia FLUVIATILIS) AND “COSTERO” (Sotalia GUIANENSIS) DOLPHINS
Marine Mammal Science, 2007Co-Authors: Susana Caballero, Fernando Trujillo, Juliana A. Vianna, Héctor Barrios-garrido, M. G. Montiel, Sandra Beltran-pedreros, Miriam Marmontel, Marcos César De Oliveira Santos, Marcos R. Rossi-santos, Fabrício R. SantosAbstract:Dolphins of the genus Sotalia are found along the Caribbean and Atlantic coasts of Central and South America and in the Amazon River and most of its tributaries. At present, the taxonomy of these dolphins remains unresolved. Although five species were described in the late 1800s, only one species is recognized currently (Sotalia fluviatilis) with two ecotypes or subspecies, the coastal subspecies (Sotalia fluviatilis guianensis) and the riverine subspecies (Sotalia fluviatilis fluviatilis). Recent morphometric analyses, as well as mitochondrial DNA analysis, suggested recognition of each subspecies as separate species. Here we review the history of the classification of this genus and present new genetic evidence from ten nuclear and three mitochondrial genes supporting the elevation of each subspecies to the species level under the Genealogical/Lineage Concordance Species Concept and the criterion of irreversible divergence. We also review additional evidence for this taxonomic revision from previously published and unpublished genetic, morphological, and ecological studies. We propose the common name “costero” for the coastal species, Sotalia guianensis (Van Beneden 1864), and accept the previously proposed “tucuxi” dolphin, Sotalia fluviatilis (Gervais, 1853), for the riverine species.
Haydée A. Cunha - One of the best experts on this subject based on the ideXlab platform.
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Phylogenetic status and timescale for the diversification of Steno and Sotalia dolphins.
PloS one, 2011Co-Authors: Haydée A. Cunha, Vera M. F. Da Silva, José Lailson-brito, Lucas C. Moraes, Bruna V. Medeiros, Antonio M. Solé-cava, Carlos G. SchragoAbstract:Molecular data have provided many insights into cetacean evolution but some unsettled issues still remain. We estimated the topology and timing of cetacean evolutionary relationships using Bayesian and maximum likelihood analyses of complete mitochondrial genomes. In order to clarify the phylogenetic placement of Sotalia and Steno within the Delphinidae, we sequenced three new delphinid mitogenomes. Our analyses support three delphinid clades: one joining Steno and Sotalia (supporting the revised subfamily Stenoninae); another placing Sousa within the Delphininae; and a third, the Globicephalinae, which includes Globicephala, Feresa, Pseudorca, Peponocephala and Grampus. We also conclude that Orcinus does not belong in the Globicephalinae, but Orcaella may be part of that subfamily. Divergence dates were estimated using the relaxed molecular clock calibrated with fossil data. We hypothesise that the timing of separation of the marine and Amazonian Sotalia species (2.3 Ma) coincided with the establishment of the modern Amazon River basin.
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Twelve microsatellite loci for marine and riverine tucuxi dolphins ( Sotalia guianensis and Sotalia fluviatilis )
Molecular Ecology Notes, 2007Co-Authors: Haydée A. Cunha, Phillip C. WattsAbstract:Twelve dinucleotide polymorphic microsatellite loci were isolated from the marine tucuxi dolphin ( Sotalia guianensis ). Levels of genetic diversity were assessed using 34 individuals from the coasts of Rio de Janeiro and Para, Brazil. Numbers of alleles varied between two and 14, and observed and expected heterozygosities ranged from 0.040 to 0.704, and from 0.093 to 0.818, respectively. Moreover, eight of these loci were variable in the riverine tucuxi Sotalia fluviatilis . This is the first description of microsatellite primers from a dolphin that does not belong to the Delphininae. These loci are currently being used in the analysis of population structure of both tucuxi species.
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Molecular sexing of tucuxi dolphins (Sotalia guianensis and Sotalia fluviatilis) using samples from biopsy darting and decomposed carcasses
Genetics and Molecular Biology, 2007Co-Authors: Haydée A. Cunha, Antonio M. Solé-cavaAbstract:We tested the zinc-finger sex chromosome-linked genes Zfx/Zfy and the sex-determining region Y (Sry) genes for gender determination of biopsy samples from marine and riverine tucuxi dolphins (Sotalia guianensis and S. fluviatilis). We also evaluated the performance of these genes with decomposed carcasses, for which sexing cannot rely on the direct examination of the reproductive tract. Both systems proved reliable for sexing 46 fresh and decomposed samples, making them especially useful when biopsy darting is coupled with photo-identification studies.
Sandra Beltran-pedreros - One of the best experts on this subject based on the ideXlab platform.
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Initial description of Major Histocompatibility Complex variation at two Class II loci (DQA-DQB) in Sotalia fluviatilis and Sotalia guianensis
Latin American Journal of Aquatic Mammals, 2010Co-Authors: Susana Caballero, Fernando Trujillo, Juliana A. Vianna, Héctor Barrios-garrido, M. G. Montiel, Sandra Beltran-pedreros, Miriam Marmontel, Marcos César De Oliveira Santos, D. Heimeier, Marcos R. Rossi-santosAbstract:Genes of the major histocompatibility complex (MHC) play a key role in the initiation of immune response in jawed vertebrates. Variation at MHC loci can be used as an indicator of the genetic ‘health’ of natural populations and offer insight into potential susceptibility to epizootics. Here we present the first characterization of the sequence variation at two MHC class II loci (DQA and DQB) in the neotropical coastal ( Sotalia guianensis ) and riverine ( Sotalia fluviatilis ) dolphins, using cloning and direct sequencing of amplified genomic DNA. Four DQA and four DQB alleles were identified in 33 and 32 Sotalia samples, respectively, and high nucleotide diversity among these alleles was detected, similar to the findings described for other cetacean species. Positive selection was evidenced by an excess of d n /d s at the Peptide-Binding-Region of the DQB of Sotalia . The presence of common alleles at both loci in S. fluviatilis and S. guianensis are consistent with trans-species mode of evolution in the MHC. In contrast to observed low levels of mtDNA diversity at the population level, there was an apparent lack of reduction of DQA and DQB allelic variation in the Brazilian Coast population unit. This suggests either present or past balancing selection acting to maintain MHC variation in this population unit.
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MITOCHONDRIAL DNA DIVERSITY, DIFFERENTIATION AND PHYLOGEOGRAPHY OF THE SOUTH AMERICAN RIVERINE AND COASTAL DOLPHINS Sotalia FLUVIATILIS AND Sotalia GUIANENSIS
Latin American Journal of Aquatic Mammals, 2010Co-Authors: Susana Caballero, Fernando Trujillo, Juliana A. Vianna, Héctor Barrios-garrido, Sandra Beltran-pedreros, Miriam Marmontel, Maria G. Montiel, O. Santos, Marcos R. Rossi-santosAbstract:Here we consider the phylogeography and population structure of the South American coastal and riverine dolphins, Sotalia guianensis and Sotalia fluviatilis, based on samples (n = 76) collected across more than 9000km of the species distribution. Phylogenetic reconstruction of 31 distinct haplotypes based on a combined analysis of two mitochondrial gene fragments (1052bp) revealed clear genetic differences between riverine and coastal individuals consistent with species-level ranking. Within the coastal species, a spatial analysis of molecular variance of the control region sequences showed significant regional population differentiation (FST = 0.4; FST = 0.6; P
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Molecular systematics of South American dolphins Sotalia: Sister taxa determination and phylogenetic relationships, with insights into a multi-locus phylogeny of the Delphinidae
Molecular phylogenetics and evolution, 2007Co-Authors: Susana Caballero, Héctor Barrios-garrido, Sandra Beltran-pedreros, Jennifer A. Jackson, Antonio A. Mignucci-giannoni, Marı´a G. Montiel-villalobos, Kelly M. Robertson, C. Scott BakerAbstract:The evolutionary relationships among members of the cetacean family Delphinidae, the dolphins, pilot whales and killer whales, are still not well understood. The genus Sotalia (coastal and riverine South American dolphins) is currently considered a member of the Stenoninae subfamily, along with the genera Steno (rough toothed dolphin) and Sousa (humpbacked dolphin). In recent years, a revision of this classification was proposed based on phylogenetic analysis of the mitochondrial gene cytochrome b, wherein Sousa was included in the Delphininae subfamily, keeping only Steno and Sotalia as members of the Stenoninae subfamily. Here we investigate the phylogenetic placement of Sotalia using two mitochondrial genes, six autosomal introns and four Y chromosome introns, providing a total of 5,196 base pairs (bp) for each taxon in the combined dataset. Sequences from these genomic regions were obtained for 17 delphinid species, including at least one species from each of five or six currently recognized subfamilies plus five odontocete outgroup species. Maximum Parsimony, Maximum Likelihood and Bayesian phylogenetic analysis of independent (each fragment) and combined datasets (mtDNA, nuDNA or mtDNA+nuDNA) showed that Sotalia and Sousa fall within a clade containing other members of Delphininae, exclusive of Steno. Sousa was resolved as the sister taxon to Sotalia according to analysis of the nuDNA dataset but not analysis of the mtDNA or combined mtDNA+nuDNA datasets. Based on the results from our multi-locus analysis, we offer several novel changes to the classification of Delphinidae, some of which are supported by previous morphological and molecular studies.
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TAXONOMIC STATUS OF THE GENUS Sotalia: SPECIES LEVEL RANKING FOR “TUCUXI” (Sotalia FLUVIATILIS) AND “COSTERO” (Sotalia GUIANENSIS) DOLPHINS
Marine Mammal Science, 2007Co-Authors: Susana Caballero, Fernando Trujillo, Juliana A. Vianna, Héctor Barrios-garrido, M. G. Montiel, Sandra Beltran-pedreros, Miriam Marmontel, Marcos César De Oliveira Santos, Marcos R. Rossi-santos, Fabrício R. SantosAbstract:Dolphins of the genus Sotalia are found along the Caribbean and Atlantic coasts of Central and South America and in the Amazon River and most of its tributaries. At present, the taxonomy of these dolphins remains unresolved. Although five species were described in the late 1800s, only one species is recognized currently (Sotalia fluviatilis) with two ecotypes or subspecies, the coastal subspecies (Sotalia fluviatilis guianensis) and the riverine subspecies (Sotalia fluviatilis fluviatilis). Recent morphometric analyses, as well as mitochondrial DNA analysis, suggested recognition of each subspecies as separate species. Here we review the history of the classification of this genus and present new genetic evidence from ten nuclear and three mitochondrial genes supporting the elevation of each subspecies to the species level under the Genealogical/Lineage Concordance Species Concept and the criterion of irreversible divergence. We also review additional evidence for this taxonomic revision from previously published and unpublished genetic, morphological, and ecological studies. We propose the common name “costero” for the coastal species, Sotalia guianensis (Van Beneden 1864), and accept the previously proposed “tucuxi” dolphin, Sotalia fluviatilis (Gervais, 1853), for the riverine species.
