The Sanguicolous Apostome Metacollinia luciensis Jankowski 1980 (Colliniidae, Apostomatia, Ciliophora) Is Not Closely Related to Other Sanguicolous Apostomes

The apostome family Colliniidae includes species that are adapted to the hemocoel/blood of various invertebrates, particularly crustaceans. To explore the phylogeny of these sanguicolous apostomes, Metacollinia luciensis was collected in August 2015 at Roscoff from the amphipod host, Orchestia gammarellus . Ciliates were Protargol stained and DNA was extracted. The small subunit rRNA ( SSU r RNA ) and cytochrome c oxidase subunit I ( cox 1) genes were amplified. Molecular phylogenetic analyses of the SSU r RNA genes unambiguously grouped M. luciensis with other apostomes with robust bootstrap support, but separated it distinctly from the pseudocolliniid clade. While there are only cox 1 sequences for a subset of these apostomes, M. luciensis was also distant from the pseudocolliniids and separated from them by species of the exuviotrophic apostome Hyalophysa . These results confirm the distinctness of the families Colliniidae and Pseudocolliniidae.