title: Molecular and karyological aspects of Batoidea (Chondrichthyes, Elasmobranchi) phylogeny.
abstract: Although considerable progress has been made in elucidating the relationships within the Chondrichthyes, there is no agreement as it concerns the systematics of Batoidea, the most derived superorder among cartilaginous fishes, and many different interpretations exist. Our investigation provides the first assessment of relationships among the described batoid species using sequences from both mtDNA and nuclear genes as well as karyological morphology. Our work consists primarily in reconstructing the phylogenetic relationships of Batoidea by examining the mtDNA (16S) and nuclear gene (18S) sequences from 11 batoid species. The three analytical methods (NJ, MP and Bayesian analysis) grouped Rajiformes, Myliobatiformes and Rhinobatiformes. In these trees the two torpedoes diverge from the other batoid fishes. We also compare the molecular data with the available karyological evidence, which consist of the diploid number and the karyotype morphology of eight species belonging to the four orders examined. The results show that the karyological structure in the different species is generally consistent with the various phylogenetical trees, and that Torpediniformes confirm their unique genome organization.
authors.affiliation: Department of Life Sciences, Via Vivaldi, 43, Caserta, Italy. lucia.rocco@unina2.it
authors.forename: Lucia
authors.initials: L
authors.lastname: Rocco
authors.forename: Innocenza
authors.initials: I
authors.lastname: Liguori
authors.forename: Domenico
authors.initials: D
authors.lastname: Costagliola
authors.forename: Maria A
authors.initials: MA
authors.lastname: Morescalchi
authors.forename: Fausto
authors.initials: F
authors.lastname: Tinti
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Stingo
mesh_terms: D000818:Animals; D002871:Chromosome Banding; D002875:Chromosomes / Q000235:genetics*; D018940:Elasmobranchii / Q000145:classification / Q000235:genetics*; D007621:Karyotyping; D008677:Metaphase; D010802:Phylogeny