title: Focusing on genera to improve species identification: revised systematics of the ciliate Spirostomum.
abstract: Although many papers dealing with the description of new ciliate taxa are published each year, species taxonomy and identification in most groups of the phylum Ciliophora remain confused. This is largely due to a scarcity of surveys on the systematics of immediately higher levels (genera and families) providing data for old and new species together. Spirostomum is a common and distinctive inhabitant of fresh- and brackish water environments, including artificial and eutrophic ones, and is a good model for applied ecology and symbiosis research. Despite this, only 3 of the numerous species are commonly cited, and no studies have yet confirmed their monophyly, with the consequence that reproducibility of the results may be flawed. In this paper we present morphological and molecular data for 30 Spirostomum populations representing 6 different morphospecies, some of which were collected in previously unreported countries. We performed a detailed revision of Spirostomum systematics combining literature surveys, new data on hundreds of organisms and statistical and phylogenetic analyses; our results provide insights on the evolution, ecology and distribution of known morphospecies and a novel one: Spirostomum subtilis sp. n. We also offer tools for quick species identification.
authors.affiliation: Università di Pisa, Dipartimento di Biologia, Unità di Zoologia-Antropologia. Via A. Volta 4/6, 56126 Pisa Italy. Electronic address: vboscaro@biologia.unipi.it.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Boscaro
authors.affiliation: Università di Pisa, Dipartimento di Biologia, Unità di Zoologia-Antropologia. Via A. Volta 4/6, 56126 Pisa Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Carducci
authors.affiliation: Università di Pisa, Dipartimento di Biologia, Unità di Zoologia-Antropologia. Via A. Volta 4/6, 56126 Pisa Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Barbieri
authors.affiliation: Universidade Federal de Juiz de Fora, Laboratório de Protozoologia, Brazil.
authors.forename: Marcus V X
authors.initials: MV
authors.lastname: Senra
authors.affiliation: Università di Pisa, Dipartimento di Biologia, Unità di Zoologia-Antropologia. Via A. Volta 4/6, 56126 Pisa Italy.
authors.forename: Ilaria
authors.initials: I
authors.lastname: Andreoli
authors.affiliation: Università di Pisa, Dipartimento di Biologia, Unità di Zoologia-Antropologia. Via A. Volta 4/6, 56126 Pisa Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Erra
authors.affiliation: Università di Pisa, Dipartimento di Biologia, Unità di Zoologia-Antropologia. Via A. Volta 4/6, 56126 Pisa Italy.
authors.forename: Giulio
authors.initials: G
authors.lastname: Petroni
authors.affiliation: Università di Pisa, Dipartimento di Biologia, Unità di Zoologia-Antropologia. Via A. Volta 4/6, 56126 Pisa Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Verni
authors.affiliation: Università di Pisa, Dipartimento di Biologia, Unità di Zoologia-Antropologia. Via A. Volta 4/6, 56126 Pisa Italy; St.-Petersburg State University, Department of Invertebrate Zoology, Russia.
authors.forename: Sergei I
authors.initials: SI
authors.lastname: Fokin
mesh_terms: D016798:Ciliophora / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics
chemical_list: D012337:RNA, Ribosomal, 18S
keywords: 18S rRNA.; Feulgen staining; Heterotrichea; ITS; SSU rRNA; macronucleus type