title: Molecular systematics of Tanaidacea (Crustacea: Peracarida) based on 18S sequence data, with an amendment of suborder/superfamily-level classification.
abstract: Phylogenetic relationships within Tanaidacea were analyzed based on sequence data for the 18S rRNA gene. Our results strongly supported a monophyletic group composed of Neotanaidae, Tanaoidea, and Paratanaoidea, with the first two taxa forming a clade. These results contradict three previously suggested hypotheses of relationships. Based on the molecular results, and considering morphological similarities/differences between Neotanaidomorpha and Tanaidomorpha, we demoted Suborder Neotanaidomorpha to Superfamily Neotanaoidea within Tanaidomorpha; with this change, the classification of extant tanaidaceans becomes a two-suborder, four-superfamily system. This revision required revision of the diagnoses for Tanaidomorpha and its three super-families. The results for Apseudomorpha were ambiguous: this taxon was monophyletic in the maximum likelihood and Bayesian analyses, but paraphyletic in the maximum parsimony and minimum evolution analyses.
authors.affiliation: Department of Natural History Sciences, Hokkaido University, Sapporo, Japan. k_kakui@mail.goo.ne.jp
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kakui
authors.forename: Toru
authors.initials: T
authors.lastname: Katoh
authors.forename: Shimpei F
authors.initials: SF
authors.lastname: Hiruta
authors.forename: Norio
authors.initials: N
authors.lastname: Kobayashi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kajihara
mesh_terms: D000818:Animals; D003445:Crustacea / Q000145:classification* / Q000235:genetics*; D014644:Genetic Variation; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics*
chemical_list: D012337:RNA, Ribosomal, 18S