title: Towards a phylogenetic classification of Leptothecata (Cnidaria, Hydrozoa).
abstract: Leptothecata are hydrozoans whose hydranths are covered by perisarc and gonophores and whose medusae bear gonads on their radial canals. They develop complex polypoid colonies and exhibit considerable morphological variation among species with respect to growth, defensive structures and mode of development. For instance, several lineages within this order have lost the medusa stage. Depending on the author, traditional taxonomy in hydrozoans may be either polyp- or medusa-oriented. Therefore, the absence of the latter stage in some lineages may lead to very different classification schemes. Molecular data have proved useful in elucidating this taxonomic challenge. We analyzed a super matrix of new and published rRNA gene sequences (16S, 18S and 28S), employing newly proposed methods to measure branch support and improve phylogenetic signal. Our analysis recovered new clades not recognized by traditional taxonomy and corroborated some recently proposed taxa. We offer a thorough taxonomic revision of the Leptothecata, erecting new orders, suborders, infraorders and families. We also discuss the origination and diversification dynamics of the group from a macroevolutionary perspective.
authors.affiliation: Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo Rua do Matão Trav. 14, 101, 05508-090, São Paulo, Brazil.
authors.forename: Maximiliano M
authors.initials: MM
authors.lastname: Maronna
authors.affiliation: Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo Rua do Matão Trav. 14, 101, 05508-090, São Paulo, Brazil.
authors.forename: Thaís P
authors.initials: TP
authors.lastname: Miranda
authors.affiliation: Instituto Cavanilles de Biodiversidad y Biología Evolutiva, Departamento de Zoología Universidad de Valencia, Valencia, Spain.
authors.forename: Álvaro L
authors.initials: ÁL
authors.lastname: Peña Cantero
authors.affiliation: Departamento de Zoologia, Caixa Postal 19020, Universidade Federal do Paraná, 81531-990, Curitiba, PR, Brazil.
authors.forename: Marcos S
authors.initials: MS
authors.lastname: Barbeitos
authors.affiliation: Departamento de Zoologia, Instituto de Biociências, Universidade de São Paulo Rua do Matão Trav. 14, 101, 05508-090, São Paulo, Brazil.|Centro de Biologia Marinha, Universidade de São Paulo, São Sebastião, Brazil.
authors.forename: Antonio C
authors.initials: AC
authors.lastname: Marques
mesh_terms: D000818:Animals; D037402:Hydrozoa / Q000145:classification*; D016013:Likelihood Functions; D010802:Phylogeny; D058974:Phylogeography
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