title: DNA capture reveals transoceanic gene flow in endangered river sharks.
abstract: For over a hundred years, the "river sharks" of the genus Glyphis were only known from the type specimens of species that had been collected in the 19th century. They were widely considered extinct until populations of Glyphis-like sharks were rediscovered in remote regions of Borneo and Northern Australia at the end of the 20th century. However, the genetic affinities between the newly discovered Glyphis-like populations and the poorly preserved, original museum-type specimens have never been established. Here, we present the first (to our knowledge) fully resolved, complete phylogeny of Glyphis that includes both archival-type specimens and modern material. We used a sensitive DNA hybridization capture method to obtain complete mitochondrial genomes from all of our samples and show that three of the five described river shark species are probably conspecific and widely distributed in Southeast Asia. Furthermore we show that there has been recent gene flow between locations that are separated by large oceanic expanses. Our data strongly suggest marine dispersal in these species, overturning the widely held notion that river sharks are restricted to freshwater. It seems that species in the genus Glyphis are euryhaline with an ecology similar to the bull shark, in which adult individuals live in the ocean while the young grow up in river habitats with reduced predation pressure. Finally, we discovered a previously unidentified species within the genus Glyphis that is deeply divergent from all other lineages, underscoring the current lack of knowledge about the biodiversity and ecology of these mysterious sharks.
authors.affiliation: Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources, Shanghai Ocean University, Ministry of Education, Shanghai 201306, China; Hollings Marine Laboratory, College of Charleston, Charleston, SC 29412;
authors.forename: Chenhong
authors.initials: C
authors.lastname: Li
authors.affiliation: Hollings Marine Laboratory, College of Charleston, Charleston, SC 29412;
authors.forename: Shannon
authors.initials: S
authors.lastname: Corrigan
authors.affiliation: Hollings Marine Laboratory, College of Charleston, Charleston, SC 29412;
authors.forename: Lei
authors.initials: L
authors.lastname: Yang
authors.affiliation: Hollings Marine Laboratory, College of Charleston, Charleston, SC 29412;
authors.forename: Nicolas
authors.initials: N
authors.lastname: Straube
authors.affiliation: Florida Fisheries Consultants Elasmobranch Studies, New Port Richey, FL 34655;
authors.forename: Mark
authors.initials: M
authors.lastname: Harris
authors.affiliation: Institute of Biochemistry and Biology, Faculty of Mathematics and Natural Sciences, University of Potsdam, 14476 Potsdam, Germany;
authors.forename: Michael
authors.initials: M
authors.lastname: Hofreiter
authors.affiliation: Wealth from Oceans Flagship, Commonwealth Scientific and Industrial Research Organisation Marine and Atmospheric Research, Hobart, TAS 7001, Australia.
authors.forename: William T
authors.initials: WT
authors.lastname: White
authors.affiliation: Hollings Marine Laboratory, College of Charleston, Charleston, SC 29412; naylorg@cofc.edu.
authors.forename: Gavin J P
authors.identifier: http://orcid.org/0000-0002-8731-2626
authors.initials: GJ
authors.lastname: Naylor
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D063147:Animal Distribution; D000818:Animals; D001208:Asia; D001483:Base Sequence; D004272:DNA, Mitochondrial / Q000235:genetics; D056727:Endangered Species; D051456:Gene Flow / Q000235:genetics*; D016013:Likelihood Functions; D008957:Models, Genetic; D008969:Molecular Sequence Data; D015876:Northern Territory; D010802:Phylogeny; D045483:Rivers; D054712:Salinity; D017422:Sequence Analysis, DNA; D012754:Sharks / Q000235:genetics*; D013045:Species Specificity
chemical_list: D004272:DNA, Mitochondrial
keywords: DNA; freshwater sharks; museum specimens