Population Genomics of the Critically Endangered Brazilian Merganser

The Brazilian merganser (Mergus octosetaceus) is one of the most endangered bird species in South America and comprises less than 250 mature individuals in wild environments. This is a species extremely sensitive to environmental disturbances and restricted to a few "pristine" freshwater habitats in Brazil, and it has been classified as Critically Endangered on the IUCN Red List since 1994. Thus, biological conservation studies are vital to promote adequate management strategies and to avoid the decline of merganser populations. In this context, to understand the evolutionary dynamics and the current genetic diversity of remaining Brazilian merganser populations, we used the "Genotyping by Sequencing" approach to genotype 923 SNPs in 30 individuals from all known areas of occurrence. These populations revealed a low genetic diversity and high inbreeding levels, likely due to the recent population decline associated with habitat loss. Furthermore, it showed a moderate level of genetic differentiation between all populations located in four separated areas of the highly threatened Cerrado biome. The results indicate that urgent actions for the conservation of the species should be accompanied by careful genetic monitoring to allow appropriate in situ and ex situ management to increase the long-term species' survival in its natural environment.

Genetic diversity and population structure of two Euglossini bee species in a host-parasite relationship

In the current study, two euglossine species, Exaerete smaragdina and Eulaema nigrita, a cleptoparasite bee and its host, respectively, were used as models to: (i) access the genetic diversity and population structure of both species, sampled along a wide latitudinal range of Atlantic Forest, where the distribution of El. nigrita and Ex. smaragdina co-occurs; (ii) investigate the evolutionary history of these species through the Atlantic Forest, and in a wider scenario, to examine the evolutionary history of these species across others forest domains. Analyses involved males of El. nigrita and Ex. smaragdina sampled through Brazilian territory, including 19 sites in the Atlantic Forest. Bayesian Skyline Plot (BSP) was used to infer possible climate oscillations on population of both species over time. The BSP revealed stability in effective population size for both species in most of the Plio-Pleistocene period. However, BSP results aligned to the starlike configuration in the haplotype network, neutrality test, and population diversity patterns indicated population expansion of the two species during the late Pleistocene. Our findings suggest areas of potential refugia to the climatic oscillations of the Pleistocene in the Atlantic Forest in the Brazilian states of Espírito Santo for El. nigrita and Pernambuco for Ex. smaragdina.

Eufriesea zhangi sp. n. (Hymenoptera: Apidae: Euglossina), a new orchid bee from Brazil revealed by molecular and morphological characters

Eufriesea zhangi Nemésio & Santos Júnior sp. n. is described from the 'Parque Nacional de Ubajara', state of Ceará, northeastern Brazil. This orchid-bee species is superficially similar to the blackish species belonging to the Eufriesea mussitans (Fabricius, 1787) species-group. Molecular and morphological (both external and genital) characters were used to demonstrate that Eufriesea zhangi sp. n. is distinct from morphologically similar Eufriesea nordestina (Moure, 1999) and Eufriesea auriceps (Friese, 1899). Molecular data vaguely suggested that its closest relative is Eufriesea nigrohirta (Friese, 1899). This new species, as well as the recently described Eulaema quadragintanovem Nemésio & Ferrari, 2012, seems to be geographically restricted to 'brejos de altitude'-Atlantic Forest physiognomies at the top of mountains in northeastern Brazil-in the state of Ceará. Due to their conspicuous isolation, these areas appear to be a rich source of unknown species that may rapidly vanish due to environmental disturbances.