Study On The Species Diversity Of Bdelloid Rotifers In Guangdong Province And The Genetic Differentiation Of Rotaria Sordida

The subclass Bdelloidea belonged to the class Eurotatoria of the phylum Rotifera are a unique group of rotifers and widely distributed in various aquatic and terrestrial habitats due to their two characteristics of obligatory parthenogenesis and anhydrobiosis.In the present study,Guangdong Province was chosen as the main research area to study the species diversity of bdelloid rotifers based on traditional morphological and molecular methods.The population genetic differentiation of wide-spread species,Rotaria sordida was studied and twelve cryptic species were found at the molecular level.The main results are as follows:(1)A total of 53 species were identified,including 9 species of genus Adineta,7species of Habrotrocha,2 species of Otostephanos,13 species of Macrotrochala,13 species of Philodina,2 species of Rotaria,2 species of Henoceros,and 1 species in genus Pleuretra,Mniobia,Bradyscela,Didymodactylos and Scepanotrocha.There is1 newly recorded family,3 newly recorded genera and 10 newly recorded species of bdelloid rotifers in China in the present study.The number of records of bdelloid rotifers in China increased from 88 to 98,and the morphological and structural characteristics of 10 new species and 3 species without described in China were described in detail.There were 35 species of bdelloid rotifers identified in moss habitats,21 species in fallen leaf habitats and 7 species in aquatic environment.Ten species were found in both moss and fallen leaf habitats,1 species in both moss and water environment,while no specie was found in all three habitats.(2)Thirty-seven CO? gene sequences from 16 bdelloid rotifer species belonged to four genera were obtained,and phylogenetic trees were constructed.Among them,the CO? gene sequences from 9 species are the first reported in China,and the CO? gene sequences from 2 species are the first recorded in the world.Results showed that species belonged to the same genus have a high degree of homology and species with similar feature often have a small genetic distance.(3)The population genetic differentiation of Rotaria sordida was studied.Twelve samples from 10 provinces and 12 cities in China were collected,and 32 CO?gene sequences of R.sordida were obtained.R.sordida in the same habitat type have high homology from various regions.Through GMYC model,the phylogeny and evolution of R.sordida were analyzed,and 12 cryptic species were found.With gene sequences from other countries downloaded from the Gen Bank,a total of 28 cryptic species were found globally.Results shows that the wide-spread species,R.sordida has high hidden diversity.The cryptic species may be caused by habitat environment,and geographic isolation may be not the main factor.Generally,the species diversity of bdelloid rotifers was studied,which increased the species richness of bdelloid rotifers in China,and supplemented the relevant data for the study of global biogeographic distribution pattern of rotifer species.