Search

Delimiting recently diverged species is challenging. During speciation, genetic differentiation may be distributed unevenly across the genome, as different genomic regions can be subject to different selective pressures and evolutionary histories. Reliance on limited numbers of genetic markers that may be underpowered can make species delimitation even more challenging, potentially resulting in taxonomic inconsistencies. Rockhopper penguins of the genus Eudyptes comprise three broadly recognized taxa: northern (E. moseleyi), southern (E. chrysocome) and eastern rockhopper (E. filholi). Their taxonomic status has been controversial for decades, with researchers disagreeing about whether E. chrysocome and E. filholi are distinct species or conspecific. Our goal is to evaluate genome-wide patterns of divergence to evaluate genetic differentiation and species delimitation in rockhopper penguins, and to assess which mechanisms may underlie previous discordance among nuclear versus mitochondrial analyses.

The conservation of biodiversity is hampered by data deficiencies, with many new species and subspecies awaiting description or reclassification. Population genomics and ecological niche modelling offer complementary new tools for un-covering functional units of phylogenetic diversity. We hypothesize that phyloge-netically delineated lineages of gentoo penguins (Pygoscelis papua) distributed across Antarctica and sub-Antarctic Islands are subject to spatially explicit ecological con-ditions that have limited gene flow, facilitating genetic differentiation, and thereby speciation processes.

An active Magellanic penguin (Spheniscus magellanicus) colony has been established on Martillo Island, Beagle Channel (54°54´26” S; 67°22´58” W) since 1976. It is located in remnants of eroded drumlins placed in both ending and joined by gravel terraces of glaciofluvial and marine origin. Forest patches occupy the eastern side of the island while most of the island is covered by bushes, tussocks and grasses. This paper presents penguins as bio-erosion agents on glacial and marine landforms. An analysis of multiple criteria surveyed in the field was performed, using Quantum GIS® 3.2.1 with remote sensing images and a digital model terrain of 12 m resolution. The morphometric data and multicriterial evaluation were collected during 2016-2017 austral summer. Soils and sediments of each landform (drumlin, glaciofluvial terrace, raised beach and beach) were sampled for particle size analysis, to determine if there is any relationship between the morphometric parameters of the cave and the sediments. Four bio-erosion classes were defined based on the erosion features observed in the field. “Moderate” was the prevailing erosion class recorded, in the E-NE part of the island. Bio-erosion features are mainly developed on the N facing slope of the east of the island, where a natural gully drains rainfall water, and over the glaciofluvial and marine terrace surfaces. Erosive features such as caves and bridges are mainly developed in silty drumlins. Pedestals are developed on bare soils and tussocks. Trails and cracks were also described as bio-erosion. No erosive features were recorded in the W part of the island. The bio-erosion map is one of the inputs for environmental degradation analysis and population dynamic research which is being done in the Magellanic penguin colony on Martillo Island, Beagle Channel., Desde 1976 en la Isla Martillo (Canal Beagle, 54°54´26” S; 67°22´58” O) se asienta una colonia de pingüinos de Magallanes (Spheniscus magellanicus). Allí se identifican geoformas de origen glacial y marino, entre las que se destacan: drumlin, terrazas glacifluviales y marinas, y playas. La vegetación de la isla está compuesta por fragmentos bosque localizados mayoritariamente en el E de la isla, y la superficie restante está cubierta de arbustos, matas y pastos. Este trabajo presenta a los pingüinos como agentes erosivos en las geoformas terrestres, glaciares y marinas. Se realizó una evaluación multi-criterio de relevamiento de campo. La geo data base se trabajó en el entorno GIS Quantum GIS® 3.2.1, utilizando imágenes satelitales y un modelo digital del terreno (MDT) de 12 m de resolución espacial, como base de referencia visual. Los datos morfométricos y la evaluación multi-criterio se recopilaron durante el verano austral 2016-2017. Se tomaron muestras de los suelos y sedimentos de cada forma de relieve (drumlin, terraza glacifluvial, playa elevada y playa) para analizar el tamaño de partícula, para determinar si existe alguna relación entre los parámetros morfométricos de la cueva y los sedimentos. Se definieron cuatro clases de bioerosión en función de las características de erosión observadas en el campo. "Moderada" fue la clase de erosión predominante, en la parte E-NE de la isla. Los rasgos erosivos se desarrollan principalmente en la ladera con orientación N del E de la isla, donde un barranco natural drena el agua de lluvia y sobre las superficies de las terrazas glacifluviales y marinas. Las características erosivas como las cuevas y los puentes se desarrollan principalmente en drumlins limosos. Los pedestales se desarrollan en suelos desnudos y matas. Los senderos y las grietas también se describieron como bioerosión. No se registraron características erosivas en la parte oeste de la isla. El mapa de bioerosión es uno de los insumos para el análisis de

[Aim]: The conservation of biodiversity is hampered by data deficiencies, with many new species and subspecies awaiting description or reclassification. Population genomics and ecological niche modelling offer complementary new tools for uncovering functional units of phylogenetic diversity. We hypothesize that phylogenetically delineated lineages of gentoo penguins (Pygoscelis papua) distributed across Antarctica and sub-Antarctic Islands are subject to spatially explicit ecological conditions that have limited gene flow, facilitating genetic differentiation, and thereby speciation processes. [Location]: Antarctica and sub-Antarctic area. [Methods]: We identify divergent lineages for gentoo penguins using ddRAD-seq and mtDNA, and generated species distribution models (SDMs) based on terrestrial and marine parameters. Results: Analyses of our genomic data supports the existence of four major lineages of gentoo penguin: (i) spanning the sub-Antarctic archipelagos north of the Antarctic Polar Front (APF); (ii) Kerguelen Island; (iii) South America; and (iv) across maritime Antarctic and the Scotia Arc archipelagos. The APF, a major current system around Antarctica, acts as the most important barrier separating regional sister lineages. Our ecological analyses spanning both the terrestrial (breeding sites) and marine (feeding sites) realms recover limited niche overlap among the major lineages of gentoo penguin. We observe this pattern to correspond more closely with regional differentiation of marine conditions than to terrestrial macroenvironmental features. [Main conclusions]: Recognition of regional genetic lineages as discrete evolutionary entities that occupy distinct ecological niches and also differ morphologically should be considered a priority for conservation. Gentoo penguins provide a good example of how conservation policy can be directly impacted by new insights obtained through the integration of larger genomic datasets with novel approaches to ecologic

Over evolutionary time, pathogen challenge shapes the immune phenotype of the host to better respond to an incipient threat. The extent and direction of this selection pressure depend on the local pathogen composition, which is in turn determined by biotic and abiotic features of the environment. However, little is known about adaptation to local pathogen threats in wild animals. The Gentoo penguin (Pygoscelis papua) is a species complex that lends itself to the study of immune adaptation because of its circumpolar distribution over a large latitudinal range, with little or no admixture between different clades. In this study, we examine the diversity in a key family of innate immune genes-the Toll-like receptors (TLRs)-across the range of the Gentoo penguin. The three TLRs that we investigated present varying levels of diversity, with TLR4 and TLR5 greatly exceeding the diversity of TLR7. We present evidence of positive selection in TLR4 and TLR5, which points to pathogen-driven adaptation to the local pathogen milieu. Finally, we demonstrate that two positively selected cosegregating sites in TLR5 are sufficient to alter the responsiveness of the receptor to its bacterial ligand, flagellin. Taken together, these results suggest that Gentoo penguins have experienced distinct pathogen-driven selection pressures in different environments, which may be important given the role of the Gentoo penguin as a sentinel species in some of the world's most rapidly changing environments.