A tale of two chitons: is habitat specialisation linked to distinct associated bacterial communities?

摘要: Although most chitons (Mollusca: Polyplacophora) are shallow-water molluscs, diverse species also occur in deep-sea habitats. We investigated the feeding strategies of two species, Leptochiton boucheti and Nierstraszella lineata, recovered on sunken wood sampled western Pacific, close to Vanuatu Islands. The display distinctly different associations with bacterial partners. harbours Mollicutes regions its gut epithelium has no abundant bacterium associated gill. lineata displays dense gut-associated bacteria, but filaments attached gill epithelium, related Deltaproteobacteria symbionts found gills wood-eating limpet Pectinodonta sp. Stable carbon nitrogen isotope signatures an absence cellulolytic activity give evidence against a direct wood-feeding diet; both secondary consumers within food web. suggest that distinct partners linked niche specialisations species. is taxonomic family restricted possibly adapted more anoxic conditions thanks gill-associated bacteria. phylogenetically proximate ancestral form not specialised may itself be generalist; this observation congruent association Mollicutes, clade comprising bacteria occurring several metazoan phyla.