Versuriga anadyomene,a newly recorded scyphozoan jellyfish(Scyphozoa:Rhizostomae)in Chinese waters

摘要

Scyphozoans are currently causing great concern worldwide due to the effects of their blooms on the marine environment.During a field survey in Beibu Gulf,South China Sea,on 27 May 2015,we found specimens of a rhizostome jellyfish that had not previously been recorded in Chinese seas.The morphological characters and DNA sequences of several specimens were examined in the laboratory.These specimens had the following morphological characters:hemispherical umbrella with reticular grooves;eight large semicircular velar lappets alternating with narrow lappets in each of the 8 octants;laterally fl attened mouth-arms with numerous fl at,membranous branches bearing many clubs and intermediate filaments;non-anastomosed broad perradial canals and anastomosed narrow interradial canals.The morphological characters of these rhizostome jellyfish were consistent with descriptions of Versuriga anadyomene.Furthermore,phylogenetic analysis of mitochondrial 16S rDNA and nuclear 18S rDNA gene fragments confirmed that these specimens were in the same cluster as V.anadyomene collected in Palau.Therefore,this rhizostome jellyfish was identified as V.anadyomene.This is the first record of the genus Versuriga and the species V.anadyomene in Chinese seas.The arrival of this species may be attributed to physical transport from the coastal waters of South East Asia.