Understanding how gene‐flow and selection interact across environmental gradients is essential for assessing population resilience and evaluating the deep‐refugia potential of mesophotic habitats under rapid climate change. In the context of depth, genetic connectivity patterns have been documented for broadcast‐spawning species, but that of brooding marine invertebrates remains largely unexplored, leaving the role of mesophot...

Aim Genetic connectivity and local adaptation were examined across the distribution of the freshwater sponge Ephydatia muelleri . Because it occupies an exceptional breadth of freshwater environments across a broad geographic range, this species offers key insights into biogeographic processes shaping genetic structure and adaptation in inland waters. Location Freshwater habitats across North America, Europe and Asia. Taxon Fr...

Approximately, 40% of earthworm species can reproduce by parthenogenesis. This is the case for the cosmopolitan species, Aporrectodea trapezoides , although sexual forms have been described sporadically. We analyse the genotypes and microbiomes of 30 individuals from four localities where both forms appear in order to understand the evolutionary mechanisms related to parthenogenesis. In all sites, heterozygosity values were ap...

Aim We assess the role of spatial distance and depth difference in shaping beta diversity patterns across abyssal seascape regions. We measured the decrease of faunistic similarity across the northeast Pacific seafloor, to test whether species turnover rates differ between deep and shallow‐abyssal biogeographical provinces and whether these patterns vary across functionally or taxonomically different biotic groups. Location Ab...

Little is known about dispersal in deep-sea ecosystems, especially for sponges, which are abundant ecosystem engineers. Understanding patterns of gene flow in deep-sea sponges is essential, especially in areas where rising pressure from anthropogenic activities makes difficult to combine management and conservation. Here, we combined population genomics and oceanographic modelling to understand how Northeast Atlantic populatio...

Invasive species are among the most important, growing threats to food security and agricultural systems. The Mediterranean medfly, Ceratitis capitata , is one of the most damaging representatives of a group of rapidly expanding species in the family Tephritidae, due to their wide host range and high invasiveness potential. Here, we used restriction site‐associated DNA sequencing (RADseq) to investigate the population genomic...

Most animals, including sponges (Porifera), have species‐specific microbiomes. Which genetic or environmental factors play major roles structuring the microbial community at the intraspecific level in sponges is, however, largely unknown. In this study, we tested whether geographic location or genetic structure of conspecific sponges influences their microbial assembly. For that, we used three sponge species with different rat...

Bone-eating worms of the genus Osedax (Annelida, Siboglinidae) form unique holobionts (functional entity comprising host and associated microbiota), highly adapted to inhabit bone tissue of marine vertebrates. These gutless worms have developed nutritional symbioses housing intracellular, horizontally acquired, heterotrophic bacteria hypothesised to harness nutrients from organic compounds, sequestered within the bone. Despite...

Antarctic shallow‐water invertebrates are exceptional candidates to study population genetics and evolution, because of their peculiar evolutionary history and adaptation to extreme habitats that expand and retreat with the ice sheets. Among them, sponges are one of the major components, yet population connectivity of none of their many Antarctic species has been studied. To investigate gene flow, local adaptation and resilien...

The abyssal demosponge Plenaster craigi inhabits the Clarion‐Clipperton Zone ( CCZ ) in the northeast Pacific, a region with abundant seafloor polymetallic nodules with potential mining interest. Since P. craigi is a very abundant encrusting sponge on nodules, understanding its genetic diversity and connectivity could provide important insights into extinction risks and design of marine protected areas. Our main aim was to ass...

Shallow‐water polychaetes are abundant and diverse components of the Southern Ocean benthic communities, and although they have been widely studied, new species that are relatively common are still discovered. Here, we report the discovery of Pterocirrus giribeti sp. n., a new and abundant intertidal and upper‐subtidal Antarctic phyllodocid. To establish the phylogenetic relationships of the new species, we sequenced two nucle...

Over the past several years, there has been growing interest in how bones of decaying mammals are colonized in the marine seabed. One of the most common opportunistic taxa occurring worldwide on bones is dorvilleid polychaetes of the genus Ophryotrocha . In a recent study in the Mediterranean, Ophryotrocha puerilis and Ophryotrocha alborana were two of the most abundant species occurring in experimentally deployed bones. These...

Invertebrate and microbial marine communities associated with mammal bones are interesting and poorly understood habitats, mainly known from studies on deep‐water whale remains. In order to characterize these communities in the shallow‐water Mediterranean, we present here the results of a pioneering experiment using mammal bones. Minke whale, pig and cow bones were experimentally deployed on three different background communit...