Morphology and diet are decoupled in nearshore notothenoids from King George Island, West Antarctica.

Antarctic notothenioid fishes show wide adaptive morphological radiation, linked to habitat preferences and food composition. However, direct comparisons of phenotypic variability and feeding habits are still lacking, particularly in stages inhabiting nearshore areas. To assess these relationships, we collected juveniles and adults of the most common benthic species inhabiting shallow waters off the South Shetland Islands within a similar size range, the plunderfish Harpagifer antarcticus, the black rockcod Notothenia coriiceps, and the marbled rockcod Notothenia rossii.

Genomics of Secondarily Temperate Adaptation in the Only Non-Antarctic Icefish.

White-blooded Antarctic icefishes, a family within the adaptive radiation of Antarctic notothenioid fishes, are an example of extreme biological specialization to both the chronic cold of the Southern Ocean and life without hemoglobin. As a result, icefishes display derived physiology that limits them to the cold and highly oxygenated Antarctic waters. Against these constraints, remarkably one species, the pike icefish Champsocephalus esox, successfully colonized temperate South American waters.

Patterns and drivers of benthic macroinvertebrate assemblages in the kelp forests of southern Patagonia.

The kelp forests of southern Patagonia have a large diversity of habitats, with remote islands, archipelagos, peninsulas, gulfs, channels, and fjords, which are comprised of a mixture of species with temperate and sub-Antarctic distributions, creating a unique ecosystem that is among the least impacted on Earth. We investigated the distribution, diversity, and abundance of marine macroinvertebrate assemblages from the kelp forests of southern Patagonia over a large spatial scale and examined the environmental drivers contributing to the observed patterns in assemblage composition. We analyzed data from 120 quantitative underwater transects (25 x 2 m) conducted within kelp forests in the southern Patagonian fjords in the Kawésqar National Reserve (KNR), the remote Cape Horn (CH) and Diego Ramírez (DR) archipelagos of southern Chile, and the Mitre Peninsula (MP) and Isla de los Estados (IE) in the southern tip of Argentina.

Unraveling the morphological patterns of a subantarctic eelpout: a geometric morphometric approach.

Phenotypic variation in organisms depends on the genotype and the environmental constraints of the habitat that they exploit. Therefore, for marine species inhabiting contrasting aquatic conditions, it is expected to find covariation between the shape and its spatial distribution. We studied the morphology of the head and cephalic sensory canals of the eelpout Austrolycus depressiceps (4.

Assemblage structure and spatial diversity patterns of kelp forest-associated fishes in Southern Patagonia.

Knowledge of the ecology of the fish fauna associated with kelp (primarily Macrocystis pyrifera) forests in Southern Patagonia is scarce, especially in how abiotic and biotic variables influence their structure, diversity, and distribution. This information is important for the management and conservation of this unique ecosystem, which has minimal anthropogenic impacts at present. We analyzed data from 122 quantitative underwater transects conducted within kelp forests at 61 stations from Chile's southern Patagonian fjords to the Cape Horn and Diego Ramirez archipelagos and the southern tip of Argentina, including the Mitre Peninsula and Isla de los Estados.

Marine communities of the newly created Kawésqar National Reserve, Chile: From glaciers to the Pacific Ocean.

The newly created Kawésqar National Park (KNP) and National Reserve (KNR) in southern Chile consists of diverse terrestrial and marine habitats, which includes the southern terminus of the Andes, the Southern Patagonia Ice Fields, sub-Antarctic rainforests, glaciers, fjords, lakes, wetlands, valleys, channels, and islands. The marine environment is influenced by wide ranging hydrological factors such as glacier melt, large terrigenous inputs, high precipitation, strong currents, and open ocean water masses. Owing to the remoteness, rugged terrain, and harsh environmental conditions, little is known about this vast region, particularly the marine realm.

Kelp forests at the end of the earth: 45 years later.

The kelp forests of southern South America are some of the least disturbed on the planet. The remoteness of this region has, until recently, spared it from many of the direct anthropogenic stressors that have negatively affected these ecosystems elsewhere. Re-surveys of 11 locations at the easternmost extent of Tierra del Fuego originally conducted in 1973 showed no significant differences in the densities of adult and juvenile Macrocystis pyrifera kelp or kelp holdfast diameter between the two survey periods.

The genomic basis for colonizing the freezing Southern Ocean revealed by Antarctic toothfish and Patagonian robalo genomes.

Background: The Southern Ocean is the coldest ocean on Earth but a hot spot of evolution. The bottom-dwelling Eocene ancestor of Antarctic notothenioid fishes survived polar marine glaciation and underwent adaptive radiation, forming >120 species that fill all water column niches today. Genome-wide changes enabling physiological adaptations and the rapid expansion of the Antarctic notothenioids remain poorly understood.

Marine biodiversity at the end of the world: Cape Horn and Diego Ramírez islands.

The vast and complex coast of the Magellan Region of extreme southern Chile possesses a diversity of habitats including fjords, deep channels, and extensive kelp forests, with a unique mix of temperate and sub-Antarctic species. The Cape Horn and Diego Ramírez archipelagos are the most southerly locations in the Americas, with the southernmost kelp forests, and some of the least explored places on earth. The giant kelp Macrocystis pyrifera plays a key role in structuring the ecological communities of the entire region, with the large brown seaweed Lessonia spp.

Contrasting Genetic Structure and Diversity of Galaxias maculatus (Jenyns, 1848) Along the Chilean Coast: Stock Identification for Fishery Management.

Galaxias maculatus (Pisces: Galaxiidae) commonly known as "puye" has a disjunct distribution along the Southern Hemisphere including landlocked and migratory populations at latitudes over 30°S in South America, Australia, Tasmania, and New Zealand. Chilean artisanal fishery of G. maculatus has become less important as a resource due to multiple factors including overexploitation, pollution, introduction of predators, and competitors.

Phylogeography in Galaxias maculatus (Jenyns, 1848) along Two Biogeographical Provinces in the Chilean Coast.

Major geologic and climatic changes during the Quaternary exerted a major role in shaping past and contemporary distribution of genetic diversity and structure of aquatic organisms in southern South America. In fact, the northern glacial limit along the Pacific coast, an area of major environmental changes in terms of topography, currents, and water salinity, represents a major biogeographic transition for marine and freshwater species. We used mitochondrial DNA sequences (D-loop) to investigate the consequences of Quaternary glacial cycles over the pattern of genetic diversity and structure of G.

Towards a model of postglacial biogeography in shallow marine species along the Patagonian Province: lessons from the limpet Nacella magellanica (Gmelin, 1791).

Background: Patagonia extends for more than 84,000 km of irregular coasts is an area especially apt to evaluate how historic and contemporary processes influence the distribution and connectivity of shallow marine benthic organisms. The true limpet Nacella magellanica has a wide distribution in this province and represents a suitable model to infer the Quaternary glacial legacy on marine benthic organisms. This species inhabits ice-free rocky ecosystems, has a narrow bathymetric range and consequently should have been severely affected by recurrent glacial cycles during the Quaternary.