Stranded humpback whale (Megaptera novaeangliae) (Cetacea: Balaenopteridae) in Paraná River Delta, Buenos Aires Province, Argentina. Comments on the occurrence of marine mammals in the La Plata River Basin

The humpback whale (Megaptera novaeangliae) is distributed among most oceans and seas of the globe (except Mediterranean Sea). These whales migrate from feeding regions in the Antarctic waters to breeding areas in tropical and subtropical seas. Here we report the stranding of a female young humpback whale, which was founded dead in the vicinity of the Talavera Island, in the Paraná River Delta, Buenos Aires Province, Argentina. From the analysis of mitochondrial cytochrome c oxidase subunit I gene sequences, two novel haplotypes were found, totalizing four haplotypes described for the species. In the La Plata River Basin this species was found only twice at the end of the XIX century. Thus, the new finding constitutes an important addition to the list of cetaceans that occurs in Uruguay, Paraná and La Plata Rivers.

Stranded humpback whale (Megaptera novaeangliae) (Cetacea: Balaenopteridae) in Paraná River Delta, Buenos Aires Province, Argentina. Comments on the occurrence of marine mammals in the La Plata River Basin

The humpback whale (Megaptera novaeangliae) is distributed among most oceans and seas of the globe (except Mediterranean Sea). These whales migrate from feeding regions in the Antarctic waters to breeding areas in tropical and subtropical seas. Here we report the stranding of a female young humpback whale, which was founded dead in the vicinity of the Talavera Island, in the Paraná River Delta, Buenos Aires Province, Argentina. From the analysis of mitochondrial cytochrome c oxidase subunit I gene sequences, two novel haplotypes were found, totalizing four haplotypes described for the species. In the La Plata River Basin this species was found only twice at the end of the XIX century. Thus, the new finding constitutes an important addition to the list of cetaceans that occurs in Uruguay, Paraná and La Plata Rivers.(AU)

Geographic Variation in Cranial Morphology of the Southern Mountain Cavy, Microcavia australis (Rodentia, Caviidae): Taxonomic Implications, with the Description of a New Species.

Pablo Teta, Ricardo A. Ojeda, Sergio O. Lucero, and Guillermo D'Elía (2017) We analyzed the geographic variation in cranial morphology of the Southern Mountain Cavy, Microcavia australis, throughout of its distributional range. Our analysis allows us to recognize three geographically allopatric morphotypes. These morphotypes differ in the general size and shape of the skull and discrete morphological traits of the zygomatic arch, palate and mesopterygoid fossa. Based on these results, we restrict the name australis to populations distributed in southern Argentina and west-central Andes and the name maenas to the morphotype of northwestern and central Argentina. The third morphotype occurs in the Dry Chaco ecoregion and is described here as a new species.