title: Identification of the notothenioid sister lineage illuminates the biogeographic history of an Antarctic adaptive radiation.
abstract: BACKGROUND
  Antarctic notothenioids are an impressive adaptive radiation. While they share recent common ancestry with several species-depauperate lineages that exhibit a relictual distribution in areas peripheral to the Southern Ocean, an understanding of their evolutionary origins and biogeographic history is limited as the sister lineage of notothenioids remains unidentified. The phylogenetic placement of notothenioids among major lineages of perciform fishes, which include sculpins, rockfishes, sticklebacks, eelpouts, scorpionfishes, perches, groupers and soapfishes, remains unresolved. We investigate the phylogenetic position of notothenioids using DNA sequences of 10 protein coding nuclear genes sampled from more than 650 percomorph species. The biogeographic history of notothenioids is reconstructed using a maximum likelihood method that integrates phylogenetic relationships, estimated divergence times, geographic distributions and paleogeographic history.
  
  
  RESULTS
  Percophis brasiliensis is resolved, with strong node support, as the notothenioid sister lineage. The species is endemic to the subtropical and temperate Atlantic coast of southern South America. Biogeographic reconstructions imply the initial diversification of notothenioids involved the western portion of the East Gondwanan Weddellian Province. The geographic disjunctions among the major lineages of notothenioids show biogeographic and temporal correspondence with the fragmentation of East Gondwana.
  
  
  CONCLUSIONS
  The phylogenetic resolution of Percophis requires a change in the classification of percomorph fishes and provides evidence for a western Weddellian origin of notothenioids. The biogeographic reconstruction highlights the importance of the geographic and climatic isolation of Antarctica in driving the radiation of cold-adapted notothenioids.
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA. thomas.near@yale.edu.|Yale Peabody Museum of Natural History, New Haven, CT, 06520, USA. thomas.near@yale.edu.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Near
authors.affiliation: Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA. alex.dornburg@yale.edu.
authors.forename: Alex
authors.initials: A
authors.lastname: Dornburg
authors.affiliation: Department of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, UK. richardh@earth.ox.ac.uk.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Harrington
authors.affiliation: Department Morfologia, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil. claudio@ibb.unesp.br.
authors.forename: Claudio
authors.initials: C
authors.lastname: Oliveira
authors.affiliation: School of Aquatic and Fishery Sciences and Burke Museum of Natural History and Culture, University of Washington, Seattle, WA, 98105, USA. twp@uw.edu.
authors.forename: Theodore W
authors.initials: TW
authors.lastname: Pietsch
authors.affiliation: Research and Collections, Section of Ichthyology, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles, CA, 90007, USA. thacker@nhm.org.
authors.forename: Christine E
authors.initials: CE
authors.lastname: Thacker
authors.affiliation: National Museum of Nature and Science, Tsukuba City, Ibaraki, 305-0005, Japan. satotaka@kahaku.go.jp.
authors.forename: Takashi P
authors.initials: TP
authors.lastname: Satoh
authors.affiliation: National Museum of Nature and Science, Tsukuba City, Ibaraki, 305-0005, Japan. ekata@kahaku.go.jp.
authors.forename: Eri
authors.initials: E
authors.lastname: Katayama
authors.affiliation: Section of Evolution & Ecology, University of California, Davis, CA, 95616, USA. pcwainwright@ucdavis.edu.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Wainwright
authors.affiliation: Department of Biomedical Sciences, Ohio University, Athens, OH, 45701-2979, USA. eastman@ohio.edu.
authors.forename: Joseph T
authors.initials: JT
authors.lastname: Eastman
authors.affiliation: National Institute for Mathematical and Biological Synthesis, University of Tennessee, 1122 Volunteer Blvd, Ste. 106, Knoxville, TN, 37996, USA. jbeaulieu@nimbios.org.
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Beaulieu
mesh_terms: D000818:Animals; D000864:Antarctic Regions; D019143:Evolution, Molecular; D029941:Fish Proteins / Q000235:genetics; D016013:Likelihood Functions; D010473:Perciformes / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics*; D010802:Phylogeny; D013020:South America
chemical_list: D029941:Fish Proteins