Molecular and morphological phylogenies of the Antarctic teleostean family Nototheniidae, with emphasis on the Trematominae

Abstract

Four independent molecular data sets were sequenced in order to solve longstanding phylogenetic problems among Antarctic teleosts of the family Nototheniidae. The anatomical data of Balushkin (2000) were also coded into a matrix of 106 characters in order to test the parsimony of his taxonomic conclusions. Molecular results confirm Balushkin’s Pleuragrammatinae but not his Nototheniinae. Different genes used here found the “clade A” establishing the paraphyly of the Nototheniinae sensu lato; i.e. Lepidonotothen and Patagonotothen are more closely related to the Trematominae than to Notothenia. The genus Notothenia is paraphyletic and Paranotothenia should become Notothenia. Previously no molecular data set could assign a reliable position for the genus Gobionotothen. For the first time robust results are obtained for the phylogeny among the Trematominae. Trematomus scotti is the sister-group of all others, then Trematomus newnesi emerges, then Trematomus eulepidotus. Among the crown group, three clades emerge: 1: Trematomus hansoni + Trematomus bernacchii + Trematomus vicarius; 2: Trematomus pennellii + Trematomus lepidorhinus + Trematomus loennbergii; 3: Trematomus (Pagothenia) borchgrevinki + Trematomus nicolai. Pagothenia should become Trematomus to make the genus Trematomus monophyletic. The Trematomus tree found here did not match the topology obtained with Balushkin’s morphological matrix. The tree shows that the tendencies shown by some trematomines to secondarily colonize the water column are not gained through common ancestry.