WALSH, E.J.*; DE LA RIVA, V.: Molecular systematics of the Brachionidae (Phylum Rotifera) based on internal transcribed spacers (ITS) of the nuclear ribosomal gene complex.
Rotifers play important roles in freshwater communities. Despite their ubiquity, little is known about their evolutionary relationships. From an ecological perspective brachionid rotifers have received considerable attention yet the most basic feature of their phylogeny, the monophyly of the group, has not been investigated. We have sequenced both ITS regions from representatives of 5 genera and 23 species within Brachionidae in addition to species from families Epiphanidae, Lecanidae, and Euchlanidae. Both regions contained many informative sites and each data set contained a strong phylogenetic signal as indicated by g1 values of -0.0755 (p<0.01) and -0.6688 (p<0.01) for ITS1 and ITS2, respectively. Data sets were analyzed individually and in combination using parsimony and maximum likelihood. Support for monophyly of the Brachionidae was found in all analyses. Monophyly of genera Keratella and Notholca were also supported. The position of Plationus patulus is investigated as is the placement of genus Rhinoglena.