title: A molecular approach to the tangled intrageneric relationships underlying phylogeny in Euplotes (Ciliophora, Spirotrichea).
abstract: The cosmopolitan genus Euplotes is remarkable among ciliates for its species richness. To understand the still tangled taxonomy and phylogenetic relationships within the genus, small subunit rRNA sequences of 11 morphologically defined species colonizing different habitats were determined. Euplotes 18S rRNA is unique among ciliates for its anomalous length and high evolutionary rate. Phylogenetic reconstruction pointed to a high divergence between this genus and the other Spirotrichea, together with a high variability within the genus. Some of the relationships within the Euplotes group were also resolved. Data from the literature, based on morphological features, habitat, and symbiotic relationships, have been compared with our results and are critically discussed. In many cases, the molecular phylogenetic analysis disagreed with species relatedness established on morphological and ecological grounds. The occurrence of a radiation phenomenon in the evolution of the genus is postulated.
authors.affiliation: Dipartimento di Etologia, Ecologia, Evoluzione, Università di Pisa, via A., Volta 4-6, 56126 Pisa, Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Petroni
authors.forename: Fernando
authors.initials: F
authors.lastname: Dini
authors.forename: Franco
authors.initials: F
authors.lastname: Verni
authors.forename: Giovanna
authors.initials: G
authors.lastname: Rosati
mesh_terms: D000818:Animals; D001483:Base Sequence; D016054:DNA, Protozoan / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D004777:Environment; D016812:Euplotes / Q000145:classification / Q000235:genetics* / Q000648:ultrastructure; D019143:Evolution, Molecular; D014644:Genetic Variation; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010802:Phylogeny; D016053:RNA, Protozoan / Q000737:chemistry / Q000235:genetics; D012337:RNA, Ribosomal, 18S / Q000737:chemistry / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid
chemical_list: D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D016053:RNA, Protozoan; D012337:RNA, Ribosomal, 18S