title: Coccidian parasites of fish encompass profound phylogenetic diversity and gave rise to each of the major parasitic groups in terrestrial vertebrates.
abstract: Fish are the oldest and most diverse group of vertebrates; it therefore stands to reason that fish may have been the original hosts for many types of extant vertebrate parasites. Here, we sought to determine whether coccidian parasites of fish are especially diverse. We therefore sampled such parasites from thirty-nine species of fish and tested phylogenetic hypotheses concerning their relationships, using 18S rDNA. We found compelling phylogenetic support for distinctions among at least four lineages of piscine parasites presently ascribed to the genus Goussia. Some, but not all parasites attributed to Eimeria were confirmed as such. Major taxonomic revisions are likely justified for these parasites of fish, which appear to have given rise to each of the major lineages of coccidian parasites that subsequently proliferated in terrestrial vertebrates, including those such as Toxoplasma gondii that form tissue cysts in intermediate hosts.
authors.affiliation: Beltsville Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, 10300, Baltimore Avenue, Beltsville, MD 20705, United States. Electronic address: Benjamin.rosenthal@ars.usda.gov.
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Rosenthal
authors.affiliation: Beltsville Agricultural Research Center, Agricultural Research Service, United States Department of Agriculture, 10300, Baltimore Avenue, Beltsville, MD 20705, United States.
authors.forename: Detiger
authors.initials: D
authors.lastname: Dunams-Morel
authors.affiliation: Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Hungária krt. 21, H-1143 Budapest, Hungary.
authors.forename: Gyorgyi
authors.initials: G
authors.lastname: Ostoros
authors.affiliation: Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Hungária krt. 21, H-1143 Budapest, Hungary.
authors.forename: Kálmán
authors.initials: K
authors.lastname: Molnár
mesh_terms: D000818:Animals; D003044:Coccidia / Q000145:classification* / Q000166:cytology / Q000235:genetics* / Q000302:isolation & purification; D004275:DNA, Ribosomal / Q000235:genetics; D019143:Evolution, Molecular; D005399:Fishes / Q000469:parasitology*; D017125:Genes, Protozoan; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D014714:Vertebrates / Q000469:parasitology*
chemical_list: D004275:DNA, Ribosomal
keywords: Coccidia; Evolution; Origins; Parasitism; Phylogeny; Vertebrates