Members of Calamyzinae, a clade of free-living and ectoparasitic chrysopetalids, are mainly associated with deep-sea chemosynthetic environments. The three currently known free-living calamyzin species are placed in
Vigtorniella. A new free-living calamyzin species similar to these is described here. Phylogenetic analyses of Calamyzinae using mitochondrial (cytochrome
c oxidase subunit I and
16S rDNA) and nuclear (
Histone H3 and
18S rDNA) loci showed that
Vigtorniella and the new species form a grade with respect to an ectoparasitic clade, requiring two new genera to be erected. All free-living calamyzins show a similar anterior end and chaetal morphology.
Micospina auribohnorum gen. et sp. nov. is described for the small-bodied new species from deep-sea whale falls off California and methane seeps off Costa Rica. The maximum-likelihood and Bayesian analyses show
Micospina gen. nov. as sister to the ectoparasitic clade.
Boudemos gen. nov. is named for the clade of two larger-bodied species:
Boudemos flokati gen. et comb. nov. and
Boudemos ardabilia gen. et comb. nov., which is sister group to all other Calamyzinae.
Vigtorniella is retained for the type species,
Vigtorniella zaikai (Kiseleva, 1992), with the adults found amongst bacterial mats at the boundary of the hydrogen sulphide zone in the Black Sea.
Micospina gen. nov.,
Boudemos gen. nov., and
Vigtorniella form a grade of free-living taxa that is associated with feeding on organic-enriched sediments, and the latter two taxa display ontogenetic jaw change. Jaws are absent in
Micospina auribohnorum gen. et sp. nov. and most of the calamyzin clade of parasitic forms.