title: Phylogeny of the Haplosporidia (Eukaryota: Alveolata) based on small subunit ribosomal RNA gene sequence.
abstract: The phylogenetic position of the phylum Haplosporidia was investigated with the complete small subunit rRNA gene sequences from 5 species in the phylum: Haplosporidium nelsoni and Haplosporidium costale, parasites of the eastern oyster Crassostrea virginica; Haplosporidium louisiana, a parasite of the mudcrab Panopeus herbstii; Minchinia teredinis, a parasite of shipworms (Teredo spp.) and Urosporidium crescens, a hyperparasite found in metacercariae of the trematode Megalophallus sp. in the blue crab, Callinectes sapidus. Multiple alignments of small subunit rRNA gene sequences included the 5 haplosporidian taxa and 14 taxa in the alveolate phyla Ciliophora, Dinoflagellida, and Apicomplexa. Maximum parsimony analysis placed the phylum Haplosporidia as a monophyletic group within the alveolate clade, as a taxon of equal rank with the other 3 alveolate phyla, and as a sister taxon to the clade composed of the phyla Dinoflagellida and Apicomplexa. Transversionally weighted parsimony placed the haplosporidians as a sister taxon to the ciliates. A separate analysis focused on the relationships of species in the genus Haplosporidium. Analyses were conducted with the haplosporidians as a functional ingroup, using each of the alveolate phyla individually as functional outgroups. The results indicated that species in the genus Haplosporidium do not form a monophyletic assemblage. As such, the present morphological criteria for distinguishing the genera Haplosporidium and Minchinia are insufficient.
authors.affiliation: School of Marine Science, Virginia Institute of Marine Science, College of William and Mary, Gloucester Point 23062, USA.
authors.forename: B S
authors.initials: BS
authors.lastname: Flores
authors.forename: M E
authors.initials: ME
authors.lastname: Siddall
authors.forename: E M
authors.initials: EM
authors.lastname: Burreson
mesh_terms: D000818:Animals; D001483:Base Sequence; D003386:Brachyura / Q000469:parasitology; D016054:DNA, Protozoan / Q000737:chemistry*; D004275:DNA, Ribosomal / Q000737:chemistry*; D056890:Eukaryota / Q000145:classification* / Q000235:genetics / Q000648:ultrastructure; D008969:Molecular Sequence Data; D010802:Phylogeny; D016053:RNA, Protozoan / Q000235:genetics; D012335:RNA, Ribosomal / Q000235:genetics*; D016415:Sequence Alignment; D013170:Spores / Q000648:ultrastructure
chemical_list: D016054:DNA, Protozoan; D004275:DNA, Ribosomal; D016053:RNA, Protozoan; D012335:RNA, Ribosomal