Abstract:

DNA size polymorphisms were utilized in a study of 24 natural populations of Ceratitis capitata Wiedemann (Diptera: Tephritidae) from Argentina. The first intron of alcohol dehydrogenase 1 gene (Adh1) was amplified using exon priming intron crossing-polymerase chain reaction. Three size variants were detected among the 307 samples analyzed. To better differentiate the size variants, further digestion of PCR products with the EcoRI restriction enzyme was carried out. Complete nucleotide sequences of the three-allele variants were obtained and single changes, insertions, deletions, and EcoRI recognition sites were located. Population allele frequencies were analyzed and a global mean heterozygosity (He) of 0.33 was obtained. In most populations, observed allelic frequencies conformed to Hardy–Weinberg expectations. Significant differences between provinces and sampling sites within these provinces, and among some populations were found. The average number of insects exchanged among populations (Nm) was estimated and high values were observed between Argentina and populations fromtwo African countries (Morocco and Kenya), Australia, and Hawaii (Kauai). Pest introduction sources and dispersion patterns in Argentina are discussed based on these results as well as on available bibliographical data.

Author affiliation: Lanzavecchia, Silvia Beatriz. INTA. Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina

Author affiliation: Remis, Maria Isabel. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Genética de la Estructura Poblacional; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Cladera, Jorge Luis. INTA. Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina

Author affiliation: Zandomeni, Ruben. INTA. Instituto de Microbiología y Zoología Agrícola. Laboratorio de Alta Complejidad; Argentina

Abstract:

El estudio de la estructura poblacional analiza la distribución de la variabilidad dentro y entre poblaciones naturales y examina los procesos involucrados en su mantenimiento. En el laboratorio de Genética de la Estructura Poblacional, del Departamento de Ecología Genética y Evolución (F. C. E. yN., UBA) se realizan estudios de variabilidad intra e interpoblacional empleando marcadores cromosómicos, moleculares y morfométricos en organismos de interés agronómico, evolutivo o en biología de la conservación utilizando como modelos biológicos especies de ortópteros y vertebrados marinos. Los estudios citogenéticos en ortópteros permitieron esclarecer los mecanismos de coevolución entre elementos genómicos dispensables (cromosomas B) y el genoma del hospedador (cromosomas A) y brindaron la oportunidad de analizar la variabilidad relacionada con los rearreglos cromosómicos (fusiones céntricas; inversiones pericéntricas) que modifican los grupos de ligamiento y probablemente la expresión génica. Los análisis de la variación morfométrica en relación a variables climáticas y ambientales infrieron acerca de importantes aspectos de la evolución fenotípica. Los análisis citogenéticos y morfométricos simultáneos analizaron los efectos del cariotipo y fenotipo sobre componentes de la eficacia biológica brindando evidencias directas del significado adaptativo de los polimorfismos cromosómicos. Los estudios empleando marcadores moleculares (RFLP, DAMD, RAPD) analizaron la estructura poblacional estimando el flujo génico entre poblaciones. Los estudios morfométricos y moleculares (secuencias de ADN, microsatélites) en vertebrados marinos identificaron grupos genéticamente diferenciados que son los que se desea preservar. Los estudios realizados brindaron información en la interpretación de las estrategias adaptativas de insectos plagas o implementación de unidades de manejo en planes de bioconservación.

The study of the population structure allows analyzing the distribution of the variability within and among natural populations interpreting the processes that shape variation. In the laboratory of Genetics of the Population Structure of the Department of Ecology, Genetics and Evolution (F. C. E. yN., UBA) intraspecific variability analysis are carried out using chromosome, molecular and morphometric markers in organisms of agronomic or evolutionary importance using species of grasshoppers and marine vertebrates as biological models. In Orthoptera cytogenetic studies clarifed the mechanisms of coevolution between dispensable genomic elements (chromosomes B) and the host genome (A chromosomes) and provided the opportunity to analyze the variability associated with chromosomal rearrangements (centric fusions; pericentric inversions) which modify the number of independent linkage groups. The analysis of the relationships between morphometric and climatic/environmental variables allow inferring important aspects of the phenotypic evolution. Cytogenetic and morphometric simultaneous studies analyzed the effects of the karyotype and phenotype on fitness components providing direct evidence of the adaptive significance of the chromosomal polymorphisms. Studies using molecular markers (RFLP, DAMD RAPD) analyzed the genetic population structure as well as the gene fow between populations. Morphometric and molecular studies (DNA sequences, microsatellites) in vertebrate marine identifed genetically distinct groups of organisms that should be conserved. The emerged results interpreted the adaptive strategies of Orthoptera species considered plagues as well as provided information to implement mitigation measures and plans for conservation in marine vertebrate species.

Author affiliation: Remis, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Genética de la Estructura Poblacional; Argentina

Abstract:

Sea turtles perform extensive migratory movements between feeding, developmental and nesting areas. Developmental areas for immature loggerheads turtles (Caretta caretta) are usually composed of individuals from multiple distant rookeries. Thus, impacts on such stocks usually affect multiple colonies, which require international efforts for conservation. This study describes the molecular genetic composition of the more austral foraging and developmental grounds of loggerhead sea turtles in the Atlantic Ocean and infers the possible origin and dispersal patterns of the species. Analyses were performed using shorter (380. bp) and larger (760. bp) sequences of the control region of mitochondrial DNA (mtDNA) from 24 samples of bycatch and 37 samples of stranded loggerhead sea turtles on the coast of the province of Buenos Aires, Argentina. All specimens (N=. 61) were adults and sub-adults (mean. ±. standard deviation curved carapace length CCL. =. 68.3. ±. 13.4. cm; range: 52.0 to 107.0. cm, N=. 41 individuals measured). Both shorter and longer mtDNA sequence analysis showed that in the foraging grounds of the Argentinean coast only haplotypes from Brazilian nesting areas (CC-A4. =. 98% and CC-A24. =. 2% for shorter sequences, and CC A4.2. =. 81%, CC A4.1. =. 17% and CC A24.1. =. 2% for longer sequences) were found. The homogeneous stock located relatively close to the rookery where individuals originated contradicts the paradigm of immature loggerhead sea turtles forming mixed stocks in foraging and developmental areas. The conservation of the stock in coastal areas of Argentina could benefit the nesting population in the nearby Brazilian rookeries, and could be achieved by conservation actions between these two countries, as well as Uruguay in between.

Author affiliation: Prosdocimi, Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Genética de la Estructura Poblacional; Argentina

Author affiliation: Bugoni, Leandro. Universidade Federal do Rio Grande do Norte; Brasil

Author affiliation: Albareda, Diego. Acuario del Jardín Zoológico de la Ciudad de Buenos Aires; Argentina

Author affiliation: Remis, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Genética de la Estructura Poblacional; Argentina

Abstract:

BACKGROUND: Anastrepha fraterculus is one of the most important fruit fly plagues in the American continent and only chemical control is applied in the field to diminish its population densities. A better understanding of the genetic variability during the introduction and adaptation of wild A. fraterculus populations to laboratory conditions is required for the development of stable and vigorous experimental colonies and mass-reared strains in support of successful Sterile Insect Technique (SIT) efforts. METHODS: The present study aims to analyze the dynamics of changes in genetic variability during the first six generations under artificial rearing conditions in two populations: a) a wild population recently introduced to laboratory culture, named TW and, b) a long-established control line, named CL. RESULTS: Results showed a declining tendency of genetic variability in TW. In CL, the relatively high values of genetic variability appear to be maintained across generations and could denote an intrinsic capacity to avoid the loss of genetic diversity in time. DISCUSSION: The impact of evolutionary forces on this species during the adaptation process as well as the best approach to choose strategies to introduce experimental and mass-reared A. fraterculus strains for SIT programs are discussed.

Author affiliation: Scannapieco, Alejandra Carla. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Scannapieco, Alejandra Carla. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Remis, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Genética de la Estructura Poblacional; Argentina

Author affiliation: Juri, Marianela Lucia. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina

Author affiliation: Vera, María Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; Argentina

Author affiliation: Segura, Diego Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina

Author affiliation: Cladera, Jorge Luis. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina

Author affiliation: Lanzavecchia, Silvia Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Genética; Argentina

Abstract:

Background: Anastrepha fraterculus is one of the most important fruit fly plagues in the American continent and only chemical control is applied in the field to diminish its population densities. A better understanding of the genetic variability during the introduction and adaptation of wild A. fraterculus populations to laboratory conditions is required for the development of stable and vigorous experimental colonies and mass-reared strains in support of successful Sterile Insect Technique (SIT) efforts. Methods: The present study aims to analyze the dynamics of changes in genetic variability during the first six generations under artificial rearing conditions in two populations: a) a wild population recently introduced to laboratory culture, named TW and, b) a long-established control line, named CL. Results: Results showed a declining tendency of genetic variability in TW. In CL, the relatively high values of genetic variability appear to be maintained across generations and could denote an intrinsic capacity to avoid the loss of genetic diversity in time. Discussion: The impact of evolutionary forces on this species during the adaptation process as well as the best approach to choose strategies to introduce experimental and mass-reared A. fraterculus strains for SIT programs are discussed.

Instituto de Genética

Author affiliation: Parreño, María Alejandra. INTA. Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina

Author affiliation: Scannapieco, Alejandra Carla. INTA. Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Remis, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución. Laboratorio de Genética de la Estructura Poblacional; Argentina

Author affiliation: Juri, Marianela Lucía. INTA. Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Vera, María Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia. Cátedra Terapéutica Vegetal; Argentina

Author affiliation: Segura, Diego Fernando. INTA. Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Cladera, Jorge Luis. INTA. Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina

Author affiliation: Lanzavecchia, Silvia Beatriz. INTA. Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina

Abstract:

The spectacled porpoise (Phocoena dioptrica, Lahille, 1912) is one of the cetacean species about which least is known. Most information on the biology and ecology of this species has been obtained from stranded specimens and sightings at sea. In this study, analysis of 380. bp fragment of mitochondrial DNA (mtDNA) control region sequences (N=50) was performed to provide a preliminary assessment of the genetic variation in spectacled porpoise specimens found stranded or by caught on the coast of Tierra del Fuego, Argentina. Results showed high levels of mtDNA diversity, as expected in large size and stable populations, and similar to other species of porpoises. The star-like shape phylogeny of haplotypes indicates a recent population expansion. This is the first report on the genetic variation of this species. Other lines of evidence (microsatellite loci, single-nucleotide polymorphism (SNPs)) are needed to improve our knowledge on the molecular biology of the spectacled porpoise.

Author affiliation: Pimper, Lida Elena. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Museo Acatushún de Aves y Mamíferos Marinos Australes; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Author affiliation: Prosser Goodall, Rae Natalie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Museo Acatushún de Aves y Mamíferos Marinos Australes; Argentina

Author affiliation: Remis, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina

Abstract:

The green turtle, Chelonia mydas, like other species of marine turtles, shows great migratory displacement between its nesting and feeding grounds. In an attempt to characterize the southernmost feeding grounds of this species, mtDNA sequence variation of green turtle aggregations in Argentinean waters was studied to elucidate genetic variation and infer possible origins. The goal of the present study is contemplated within the main purpose of the PRICTMA (Regional Program for Sea Turtle Research in Conservation of Argentina) and the Network ASO-Tortugas (Red Atlántico Sur Occidental-Tortugas) which are dedicated to promoting conservation studies in marine turtles in the region. A 486-bp fragment of the mitochondrial DNA control region was sequenced from 93 samples of incidentally caught juveniles from 2004 to 2007, revealing 9 haplotypes. Nucleotide and haplotype diversity were similar to those detected in other Brazilian feeding grounds (Ubatuba and Atol das Rocas/Fernando de Noronha). Analysis of molecular variance (AMOVA) indicated significant genetic differentiation among 9 western Atlantic feeding grounds for which data is currently available, suggesting variable contributions from different nesting colonies (F ST=0.29, P<10 -4; Φ ST=0.55, P<10 -4). Mitochondrial DNA haplotype distributions revealed significant heterogeneity among feeding grounds (X 2: 804.84, P<10 -4). A pairwise analysis revealed that most western Atlantic feeding grounds are genetically differentiated. The weighted and unweighted mixed stock analyses suggests that green turtles at Argentinean feeding grounds originate mainly in the Ascension Island rookery, with less contribution from rookeries in Suriname, Aves Island and Trindade Island.The present results improve our knowledge of the population structure and migration patterns of the Atlantic green turtle, and inform conservation measures on feeding grounds, which may be thousands of kilometers away from the nesting colonies. This information is required to further government efforts for this endangered species.

Author affiliation: Prosdocimi, Laura. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Fundación Mundo Marino; Argentina

Author affiliation: González Carman, Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Subsede Instituto Nacional de Investigación y Desarrollo Pesquero; Argentina. Aquamarina-CECIM-PRICTMA; Argentina

Author affiliation: Albareda, Diego. Aquamarina-CECIM-PRICTMA; Argentina. Ciudad Autónoma de Buenos Aires. Jardín Zoológico; Argentina

Author affiliation: Remis, Maria Isabel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Abstract:

Argentine populations of Dichroplus elongatus (Orthoptera: Acrididae) are polymorphic for B chromosomes. Previous studies showed that B chromosomes affect body size and some fitness components in Northwestern populations. We studied phenotype and B′s variation patterns along a latitudinal cline as well as the relationship between karyotype and body size related traits in 17 populations from East.Body size related traits showed a ‘saw tooth’ pattern of variation being small at low and high latitudes and large at intermediate latitudes in most of the analysed populations. Analyses of variance and principal components demonstrated that in most analysed populations B carrier males are associated with a decrease in body size related traits with respect to individuals with standard karyotype. Accordingly with the relationship between karyotype and body size, an opposite pattern of latitudinal variation in the frequencies of B′s with respect to body size variation was observed in this area. i.e. smaller individuals tend to have a higher frequency of B chromosomes. The comparison of the differentiation of both karyotype and body size traits with molecular neutral markers demonstrated the relative importance of selection moulding chromosome and phenotype variation. The observed pattern of phenotypic variation is likely to be the result of local adaptation to season length along the latitudinal gradient. The observed contrary pattern of B′s clinal variation may reflect the population ability to maintain this chromosome in relation to the local adaptation. The available evidence indicates that the distribution of B chromosome frequency was shaped by selective factors.

Author affiliation: Rosetti, Maria Eva Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina

Author affiliation: Remis, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina

Abstract:

The grasshopper Cornops aquaticum occurs between Mexico (23°N) and Uruguay and Central Argentina (35°S). It was recently introduced as a pest control agent of the neotropical water-hyacinth Eichhornia crassipes in South Africa. The information about the amount and distribution of genetic variability of the native populations may optimise the results of biological control programmes. Here we analyse microsatellite variability at the south of C. aquaticum’s distribution, coinciding with a cline for three polymorphic Robertsonian translocations along the Paraná River in order to: (1) estimate the amount of intrapopulation variation and its correlation with geographic/climatic variables, (2) infer interpopulation genetic variation and assess connectivity between local populations and (3) compare chromosome, morphometric and molecular variation patterns to analyse the probable causes involved in the maintenance of intraspecific variation. Our sample of 170 individuals of C. aquaticum from seven Argentine populations between latitudes 27°S to 34°S showed 211 alleles across seven microsatellite loci. Genetic diversity was estimated through average number of alleles, allelic richness, expected heterozygosity and observed heterozygosity. The analysis of molecular variance showed significant genetic differentiation among populations. Pairwise comparisons of FST/RST and Bayesian population assignment method and the discriminant analysis of principal components revealed that the two southernmost populations are more differentiated. Genetic diversity is negatively correlated with Southern latitude and with Robertsonian translocation frequencies. Our results showed that the Paraná River’s middle course populations are genetically undifferentiated and more genetically diverse than the highly chromosomally polymorphic downstream ones. The chromosomal polymorphisms are associated with increased body size in the direction in which larger size is adaptive. This may be relevant for C. aquaticum’s role as a pest control agent, since chromosome variability would enhance the ability of the species for a successful settlement in its new habitats, especially in temperate regions of the world.

Author affiliation: Romero, Maria Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina

Author affiliation: Colombo, Pablo Cesar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina

Author affiliation: Remis, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina

Abstract:

The Commerson’s dolphin, Cephalorhynchus commersonii, is found in shallow waters of the continental shelf off the eastern coast of South America between 40°S and 56°S. This species is taken incidentally in artisanal gillnet fisheries, especially along the shallow coastline of northern Tierra del Fuego and southern Patagonia. The biological importance of by-catch is likely to be underestimated if the boundaries of subpopulations are not properly defined. Here, we report on the sequence variation of the mitochondrial DNA control region of the Commerson’s dolphin from five areas defined in Tierra del Fuego, Argentina and Chile, to provide a preliminary assessment of population structure where conservation efforts are most needed. A 466 bp fragment of the mitochondrial DNA control region was sequenced from 196 samples of skin, teeth and bone, defining 20 haplotypes from 17 polymorphic sites. Nucleotide (π = 0.40%) and haplotype (h = 0.807) diversity were low compared to some other odontocete populations, but similar to that of other species of this genus. Genetic differentiation evaluated through analyses of molecular variance (AMOVA) showed significant overall differences among areas within Tierra del Fuego (ΦST = 0.059, P < 0.01). An analysis of sex-specific population structure suggested that the dispersal rates of both females and males are low, indicative of females displaying greater site fidelity. The results from mtDNA control region sequences alone revealed significant differentiation among studied areas, which should be considered as independent management units. We recommend that the impact of localized gillnet mortalities should be managed on a local scale in these areas of Tierra del Fuego.

Author affiliation: Pimper, Lida Elena. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Museo Acatushún de Aves y Mamíferos Marinos Australes; Argentina

Author affiliation: Scott Baker, C.. The University Of Auckland; Nueva Zelanda. State University of Oregon; Estados Unidos

Author affiliation: Prosser Goodall, Rae Natalie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; Argentina. Museo Acatushún de Aves y Mamíferos Marinos Australes; Argentina

Author affiliation: Olavarría, Carlos. The University Of Auckland; Nueva Zelanda. Fundación Centro de Estudios del Cuaternario; Chile

Author affiliation: Remis, Maria Isabel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ecología, Genética y Evolución; Argentina