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Molecular Phylogeny and Evolutionary Relationships between the Ciliate Genera Peniculistoma and Mytilophilus (Peniculistomatidae, Pleuronematida)
Author(s) -
Antipa Gregory A.,
Dolan John R.,
Lynn Denis H.,
Obolkina Lubov A.,
StrüderKypke Michaela C.
Publication year - 2016
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/jeu.12316
Subject(s) - biology , monophyly , paraphyly , phylogenetic tree , ciliate , sister group , zoology , taxon , phylogenetics , ribosomal rna , evolutionary biology , ecology , gene , clade , genetics
Peniculistoma mytili and Mytilophilus pacificae are placed in the pleuronematid scuticociliate family Peniculistomatidae based on morphology and ecological preference for the mantle cavity of mytiloid bivalves. We tested this placement with sequences of the small subunit rRNA ( SSU r RNA ) and cytochrome c oxidase subunit 1 ( cox1 ) genes. These species are very closely related sister taxa with no distinct genetic difference in the SSU r RNA sequence but about 21% genetic difference for cox1 , supporting their placement together but separation as distinct taxa. Using infection frequencies, M. pacificae , like its sister species P. mytili , does not interact with Ancistrum spp., co‐inhabitants of the mantle cavity. On the basis of these ecological similarities, the fossil record of host mussels, and features of morphology and stomatogenesis of these two ciliates, we argue that M. pacificae derived from a Peniculistoma ‐like ancestor after divergence of the two host mussels. Our phylogenetic analyses of pleuronematid ciliates includes the SSU r RNA gene sequence of Sulcigera comosa , a Histiobalantium ‐like ciliate from Lake Baikal. We conclude: (i) that the pleuronematids are a monophyletic group; (ii) that the genus Pleuronema is paraphyletic; and (iii) that S. comosa is a Histiobalantium species. We transfer S. comosa to Histiobalantium and propose a new combination Histiobalantium comosa n. comb.