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Vigtorniella ardabilia sp. nov., a new chrysopetalid annelid, is described from a whale-fall in Sweden and from sediment samples collected beneath fish farms in Norway. The new Vigtorniella species is morphologically almost identical to Vigtorniella flokati from whale-falls in the Pacific Ocean, although molecular evidence from four genes shows that they are different species. Population genetic structure and phylogenetic relationships of V. ardabilia sp. nov. were assessed using molecular data from the nuclear genes 18S and 28S, and the mitochondrial 16S and cytochrome c oxidase subunit I (COI). High levels of gene flow are reported between contrasting organic-rich environments in the North Atlantic (fish farms and whale-fall). Observations of feeding biology and habitat suggest that V. ardabilia specializes on bacterial mats, rather than on whale-falls, although the two species of Vigtorniella for which data were available show very different feeding behaviours. Our results further showed an unexpectedly low divergence rate in Vigtorniella for the mitochondrial markers, suggesting stabilizing selection. Analyses carried out with parsimony, maximum likelihood, and MrBayes all placed the genus Vigtorniella as sister group to Dysponetus, suggesting a close evolutionary link to sediment-dwelling fauna.

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Heavy metal discharges to the marine environment are of great concern all over the world. Both essential (e.g., Fe, Zn, Cu) and non essential (e.g., Hg, Cd, Pb) metals are toxic to living organisms when subjected to high concentrations (Underwood and Mertz 1987). Many heavy metals accumulate in organisms and some also accumulate in the food chain (Ruiter 1995). The anthropogenic heavy metal outlets can in this way both reduce marine species diversity and ecosystems. Further, by consuming seafood, humans will be exposed to the metals with a potential danger to human health. Goldberg (1975) proposed to use marine mussels to monitor contamination levels of coastal waters. Since then marine mussels, especially the blue mussel (Mytilus edulis), has been used widely as a surveillance organism (Claisse 1989;Cossa 1988). The blue mussel is regarded a suitable species for this purpose because it accumulates metals, is sessile, has a relatively long life span, is large enough for individual analysis, can tolerate a relatively wide range of temperature and salinity regimes (Phillips 1977), and can also synthesize the metal-binding protein, metallothionein, for metal detoxification (Köhler and Riisgård 1982).