Taxonomic Study On Deep-Sea Hexactinellid Sponge From The West Pacific Ocean,South China Sea And Preliminary Study Of Their Molecular Phylogeny

Porifera,commonly known as sponge,is the most primitive multicellular animal that was already present and diversified in the lower Cambrian.sponges are sedentary filter feeder animals that have considerable ecological,commercial and biopharmaceutical value.Sponges are also one of the common species in the deep sea.The morphological identification of most sponges is very difficult as the literature involve languages from several counthries.Its convergent evolution and polymorphism even confused taxonomists.To date,there are 9,125 accepted species of aarine and freshwater sponges,with at least twice as many still undiscovered.Among them,the vast majority of the class Hexactinellida(also known as glass sponges)are deep-sea species,living on hard and soft bottom from 200 m to 6000 m deep.However,the slow development of the taxonomic research on sponges in China has largely hindered the development of the related research field of sponges in China and its subsequent industrialized application.This paper bases on framework of glass sponges,focuses on taxonomic study of deep-sea samples collected during Cruise 37,Cruise 48 and Cruise KK1803 from the western Pacific,combined with molecular biology techiniques.7 individuals were identified as new species out of 10,which covers the main three orders of class Hexactinellida to a certain extent,contributed to the progresses of taxonomic study of Hexactinellid sponges in China.10 species belonging to 8 genera,4 families,3 orders were included in the study with detailed description of each species.No similar species have been recorded or reported in this region,so all species are the first reported in this region.This paper has carried molecular and phylogenetic work on the samples collected by three cruises.All experimental material of DNA extraction were carried,all 16S rDNA gene fragments and parts of 18S,28S rRNA,COI gene fragments were obtained,which showed 16S rRNA amplification efficiency is highest.The phylogenetic tree based on 16S rRNA gene fragment and multi-gene could reflect the classification status and phylogenetic relationship of the species described.The phylogeny of Hexactinellids including the described species and related species in this paper is discussed,providing important reference and molecular biological data for current Hexactinellid sponge phylogeny.