Coastal and demersal chondrichthyans(sharks,rays,and skates)are expected to exhibit high levels of genetic differentiation in areas of complex geomorphology.Population genetic studies investigating the extent to which...Coastal and demersal chondrichthyans(sharks,rays,and skates)are expected to exhibit high levels of genetic differentiation in areas of complex geomorphology.Population genetic studies investigating the extent to which demographic history shapes the genetic structure of thesefishes are rare.Here,we combined mitochondrial DNA(Cytb and ND2)and 8 nuclear microsatellite loci from 244 individuals to examine the population genetic structure and demographic history of the 3 Indo-West Pacific species of sharpnose rays(Telatrygon zugei,Telatrygon biasa,and Trygon crozieri).High levels of genetic variation both within and between species were identified.Phylogenetic analysis partitioned haplotypes into 2 lineages supporting divergence of T.zugei from T.crozieri and T.biasa during the Pleistocene.Furthermore,microsatellite-based clustering analyses identified 4 genetic groups(i.e.T.zugei from Japan,T.zugei from coastal China,T.biasa from Gulf of Thailand,and T.crozieri from the Andaman Sea).Measurements of genetic differentiation also support these 4 groups.Additionally,Pleistocene demographic expansions were examined in all genetic groups.The climate oscillations and current hydrologic cycles in the Indo-West Pacific appear to coincide with the hypothesis regarding speciation and the observed demographic history trends of the sharpnose rays.Considering the species group has,until recently,been thought to be one species,these results are critical for defining management units and guiding conservation efforts to preserve stingray biodiversity.展开更多
INTRODUCTION Sharks,skates and rays originated 400 Ma,with a further radiation throughout every ocean,and play a vital role in maintaining the balance of marine ecosystems as top predators(Weigmann 2016).T...INTRODUCTION Sharks,skates and rays originated 400 Ma,with a further radiation throughout every ocean,and play a vital role in maintaining the balance of marine ecosystems as top predators(Weigmann 2016).There are more than 1000 species of sharks,skates,rays and chimaeras in the world,244 of which are distributed in Chinese seas.That is,Chinese chondrichthyan fauna make up at least one-fifth of the world’s extant species.Recent habitat degradation and overexploitation have caused sharp declines in many populations of elasmobranchs(White 2007;Dulvy et al.2017).Environmental changes and loss of oceanic apex predators due to overfishing could affect the migration routes and distribution of batoids(rays),resulting in community restructuring in the coastal ecosystem(Yamaguchi et al.2005;Myers et al.2007).Despite the combination of known high biodiversity and heavy exploitation of elasmobranchs in China,there is little reliable information on the population genetics of many shark and ray species.Consequently,clarification of the population structure is crucial for conservation and management,especially for endangered elasmobranchs.展开更多
基金financially supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDA19050202)the Natural Science Found of China(No.31272287 and No.41666008)+1 种基金the Grants-inaid for Conservation of Fishery Resources of the Ministry of Agriculture in China(No.171721301354052003)the JSPS Invitation Fellowship Program for sampling and Research in Japan.
文摘Coastal and demersal chondrichthyans(sharks,rays,and skates)are expected to exhibit high levels of genetic differentiation in areas of complex geomorphology.Population genetic studies investigating the extent to which demographic history shapes the genetic structure of thesefishes are rare.Here,we combined mitochondrial DNA(Cytb and ND2)and 8 nuclear microsatellite loci from 244 individuals to examine the population genetic structure and demographic history of the 3 Indo-West Pacific species of sharpnose rays(Telatrygon zugei,Telatrygon biasa,and Trygon crozieri).High levels of genetic variation both within and between species were identified.Phylogenetic analysis partitioned haplotypes into 2 lineages supporting divergence of T.zugei from T.crozieri and T.biasa during the Pleistocene.Furthermore,microsatellite-based clustering analyses identified 4 genetic groups(i.e.T.zugei from Japan,T.zugei from coastal China,T.biasa from Gulf of Thailand,and T.crozieri from the Andaman Sea).Measurements of genetic differentiation also support these 4 groups.Additionally,Pleistocene demographic expansions were examined in all genetic groups.The climate oscillations and current hydrologic cycles in the Indo-West Pacific appear to coincide with the hypothesis regarding speciation and the observed demographic history trends of the sharpnose rays.Considering the species group has,until recently,been thought to be one species,these results are critical for defining management units and guiding conservation efforts to preserve stingray biodiversity.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA19050202)the National Science Fund of China(No.31272287)+1 种基金the Ministry of Agriculture of China,Grants-in-aid for Conservation of Fishery Resources under Grant No.17162130135252095the JSPS Invitation Fellowship Program for Research in Japan.
文摘INTRODUCTION Sharks,skates and rays originated 400 Ma,with a further radiation throughout every ocean,and play a vital role in maintaining the balance of marine ecosystems as top predators(Weigmann 2016).There are more than 1000 species of sharks,skates,rays and chimaeras in the world,244 of which are distributed in Chinese seas.That is,Chinese chondrichthyan fauna make up at least one-fifth of the world’s extant species.Recent habitat degradation and overexploitation have caused sharp declines in many populations of elasmobranchs(White 2007;Dulvy et al.2017).Environmental changes and loss of oceanic apex predators due to overfishing could affect the migration routes and distribution of batoids(rays),resulting in community restructuring in the coastal ecosystem(Yamaguchi et al.2005;Myers et al.2007).Despite the combination of known high biodiversity and heavy exploitation of elasmobranchs in China,there is little reliable information on the population genetics of many shark and ray species.Consequently,clarification of the population structure is crucial for conservation and management,especially for endangered elasmobranchs.
