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Host-microbe interactions are ubiquitous and play important roles in host biology, ecology, and evolution. Yet, host-microbe research has focused on inland species, whereas marine hosts and their associated microbes remain largely unexplored, especially in developing countries in the Southern Hemisphere. Here, we review the current knowledge of marine host microbiomes in the Southern Hemisphere. Our results revealed important biases in marine host species sampling for studies conducted in the Southern Hemisphere, where sponges and marine mammals have received the greatest attention. Sponge-associated microbes vary greatly across geographic regions and species. Nevertheless, besides taxonomic heterogeneity, sponge microbiomes have functional consistency, whereas geography and aging are important drivers of marine mammal microbiomes. Seabird and macroalgal microbiomes in the Southern Hemisphere were also common. Most seabird microbiome has focused on feces, whereas macroalgal microbiome has focused on the epibiotic community. Important drivers of seabird fecal microbiome are aging, sex, and species-specific factors. In contrast, host-derived deterministic factors drive the macroalgal epibiotic microbiome, in a process known as "microbial gardening". In turn, marine invertebrates (especially crustaceans) and fish microbiomes have received less attention in the Southern Hemisphere. In general, the predominant approach to study host marine microbiomes has been the sequencing of the 16S rRNA gene. Interestingly, there are some marine holobiont studies (i.e., studies that simultaneously analyze host (e.g., genomics, transcriptomics) and microbiome (e.g., 16S rRNA gene, metagenome) traits), but only in some marine invertebrates and macroalgae from Africa and Australia. Finally, we introduce an ongoing project on the surface microbiome of key species in the Strait of Magellan. This is an international project that will provide novel microbiome information of several species in the Strait of Magellan. In the short-term, the project will improve our knowledge about microbial diversity in the region, while long-term potential benefits include the use of these data to assess host-microbial responses to the Anthropocene derived climate change. [ABSTRACT FROM AUTHOR]

Sedimentary postabdominal claws, among other remains, have been used successfully in paleolimnological studies to reconstruct past environmental conditions and the distribution pattern of certain Daphnia species. However, morphological analysis of postabdominal claws has not proven adequate for the clear taxonomic differentiation among species within a complex, such as the Daphnia pulex complex. The presence of the invasive North American (NA) D. pulex lineage was recently detected in an alpine lake in the Sierra Nevada mountain range (Southeast Spain). This lineage has spread throughout Africa and the Mediterranean basin, suggesting a trend towards its increased presence in Europe. The aim of this study was to examine whether this invasive lineage could be differentiated from the native European (Eu) Daphnia pulicaria lineage based on morphological differences in postabdominal claws recovered from three alpine lakes in the Sierra Nevada. The most useful differential variables were the postabdominal claw length (PCL), ratio of distal comb length to PCL (Cldist/PCL), and number of stout spines. Thus, NA D. pulex may be identifiable by a short PCL, low Cldist/PCL value and the presence of < 5 stout spines. Because of a wide variability in PCL within the Eu D. pulicaria species and an overlap in stout spine number between the species, morphological analysis results cannot unequivocally differentiate these lineages. However, they make a useful contribution to recognition of the possible presence of this invasive lineage. The present findings assist identification of the invasive NA D. pulex lineage in potentially affected regions, facilitating reconstruction of its historic dispersion and colonization. [ABSTRACT FROM AUTHOR]

Background: The use of DNA based methods for assessing biodiversity has become increasingly common during the last years. Especially in speciose biomes as tropical rain forests and/or in hyperdiverse or understudied taxa they may efficiently complement morphological approaches. The most successful molecular approach in this field is DNA barcoding based on cytochrome c oxidase I (COI) marker, but other markers are used as well. Whereas most studies aim at identifying or describing species, there are only few attempts to use DNA markers for inventorying all animal species found in environmental samples to describe variations of biodiversity patterns. Methodology/Principal Findings: In this study, an analysis of the nuclear D3 region of the 28S rRNA gene to delimit species-like units is compared to results based on distinction of morphospecies. Data derived from both approaches are used to assess diversity and composition of staphylinid beetle communities of a Guineo-Congolian rain forest in Kenya. Beetles were collected with a standardized sampling design across six transects in primary and secondary forests using pitfall traps. Sequences could be obtained of 99% of all individuals. In total, 76 molecular operational taxonomic units (MOTUs) were found in contrast to 70 discernible morphospecies. Despite this difference both approaches revealed highly similar biodiversity patterns, with species richness being equal in primary and secondary forests, but with divergent species communities in different habitats. The D3-MOTU approach proved to be an efficient tool for biodiversity analyses. Conclusions/Significance: Our data illustrate that the use of MOTUs as a proxy for species can provide an alternative to morphospecies identification for the analysis of changes in community structure of hyperdiverse insect taxa. The efficient amplification of the D3-marker and the ability of the D3-MOTUs to reveal similar biodiversity patterns as analyses of morphospecies recommend its use in future molecular studies on biodiversity. [ABSTRACT FROM AUTHOR]