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A Molecular Phylogenetic Investigation of Opisthonecta and Related Genera (Ciliophora, Peritrichia, Sessilida)
Author(s) -
WILLIAMS DANIEL,
CLAMP JOHN C.
Publication year - 2007
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/j.1550-7408.2007.00262.x
Subject(s) - biology , monophyly , clade , phylogenetic tree , zoology , ribosomal rna , evolutionary biology , genetics , gene
. The gene encoding 18S small subunit ribosomal RNA (ssu rRNA) was sequenced in the sessiline peritrichs Opisthonecta minima and Opisthonecta matiensis , whose free‐swimming, paedomorphic trophonts resemble telotrochs. Using these new sequences, phylogenetic trees were constructed with four different methods to test a previously published association between Opisthonecta henneguyi and members of the families Vorticellidae and Astylozoidae. All trees had similar topologies, with O. minima , O . henneguyi , Vorticella microstoma , and Astylozoon enriquesi forming a well‐supported, certainly monophyletic clade. On the basis of genetic evidence, genera of the families Opisthonectidae and Astylozoidae are assigned to the family Vorticellidae, which already includes some species with free‐swimming morphotypes. The ssu rRNA sequence of O . matiensis places it in the family Epistylididae; its taxonomic revision will be left to another group of authors. A close association of Ophrydium versatile with members of the family Vorticellidae was confirmed, casting doubt on the validity of the family Ophrydiidae. Epistylis galea , Campanella umbellaria , and Opercularia microdiscum are confirmed as comprising an extremely distinct, monophyletic, but morphologically heterogeneous clade that is basal to other clades of sessiline peritrichs.