title: Molecular systematics of marine gregarine apicomplexans from Pacific tunicates, with descriptions of five novel species of Lankesteria.
abstract: The eugregarines are a group of apicomplexan parasites that mostly infect the intestines of invertebrates. The high level of morphological variation found within and among species of eugregarines makes it difficult to find consistent and reliable traits that unite even closely related lineages. Based mostly on traits observed with light microscopy, the majority of described eugregarines from marine invertebrates has been classified into a single group, the Lecudinidae. Our understanding of the overall diversity and phylogenetic relationships of lecudinids is very poor, mainly because only a modest amount of exploratory research has been done on the group and very few species of lecudinids have been characterized at the molecular phylogenetic level. In an attempt to understand the diversity of marine gregarines better, we surveyed lecudinids that infect the intestines of Pacific ascidians (i.e. sea squirts) using ultrastructural and molecular phylogenetic approaches; currently, these species fall within one genus, Lankesteria. We collected lecudinid gregarines from six ascidian host species, and our data demonstrated that each host was infected by a different species of Lankesteria: (i) Lankesteria hesperidiiformis sp. nov., isolated from Distaplia occidentalis, (ii) Lankesteria metandrocarpae sp. nov., isolated from Metandrocarpa taylori, (iii) Lankesteria halocynthiae sp. nov., isolated from Halocynthia aurantium, (iv) Lankesteria herdmaniae sp. nov., isolated from Herdmania momus, (v) Lankesteria cf. ritterellae, isolated from Ritterella rubra, and (vi) Lankesteria didemni sp. nov., isolated from Didemnum vexillum. Visualization of the trophozoites with scanning electron microscopy showed that four of these species were covered with epicytic folds, whereas two of the species were covered with a dense pattern of epicytic knobs. The molecular phylogenetic data suggested that species of Lankesteria with surface knobs form a clade that is nested within a paraphyletic assemblage species of Lankesteria with epicytic folds.
authors.affiliation: School of Life, Sport and Social Sciences, Edinburgh Napier University, Sighthill Campus, Sighthill Court, Edinburgh EH11 4BN, UK.|Shimoda Marine Research Center, University of Tsukuba, 5-10-1 Shimoda, 415-0025 Shizuoka, Japan.
authors.forename: Sonja
authors.initials: S
authors.lastname: Rueckert
authors.affiliation: Departments of Zoology and Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.|Microbiology and Biochemistry of Secondary Metabolites Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Kunigami, 904-0412 Okinawa, Japan.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Wakeman
authors.affiliation: Microbiology and Biochemistry of Secondary Metabolites Unit, Okinawa Institute of Science and Technology, 1919-1 Tancha, Kunigami, 904-0412 Okinawa, Japan.
authors.forename: Holger
authors.initials: H
authors.lastname: Jenke-Kodama
authors.affiliation: Departments of Zoology and Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
authors.forename: Brian S
authors.initials: BS
authors.lastname: Leander
mesh_terms: D000818:Animals; D016782:Apicomplexa / Q000145:classification* / Q000166:cytology / Q000302:isolation & purification; D016054:DNA, Protozoan / Q000235:genetics; D020459:Genes, rRNA; D007422:Intestines / Q000469:parasitology*; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D010140:Pacific Ocean; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D053058:Trophozoites / Q000166:cytology; D014561:Urochordata / Q000469:parasitology*
chemical_list: D016054:DNA, Protozoan