Hydromedusae from the Arctic in 2010 during the 4th Chinese National Arctic Research Expedition(CHINARE 4)

Fifty-seven stations （48 grid stations and nine stratified stations） were sampled across the study region （67.000°-88.394°N, 152.500°-178.643°W） during the 4th Chinese National Arctic Research Expedition （CHI- NARE 4） from July to August 2010 by the icebreaker R/VXuelong. A total of 24 species of Hydromedusae were identified from 130 zooplankton samples, of which seven species belonged to Automedusa, eight species to Anthomedusae, four species to Leptomedudae, and three species to Siphonophora. Catablema multicir- ratum Kishinouye, 1910, Bougainvillia bitentaculata Uchida, 1925, and Euphysajaponica （Maas, 1909） were recorded for the first time in the Arctic sea. In the present paper, 18 species of Hydromedusae were described and illustrated, of which three species were described for the first time in the Arctic sea, and 15 species were described for the first time in China.

Ecological studies on the Hydromedusae, Siphonophores and Ctenophores in the Xiamen Harbour and adjacent waters

This paper deals with species composition, seasonal change and horizontal distribution of the Hydromedusae (Hyd.), Siphonophores (Sip.) and Ctenophores (Cte.) and their relationship to the environmental factors. Materials from 17 stations in the Xiamen Harbour and adjacent waters were taken once monthly for the period from Sep. 1980 to Aug. 1981. The results indicate that for the dominant species of Phialidium folleatum, Lensia subtiloides and Pleurobrachia globosa , the total annual number of species has one peak and the total annual number of individual has one peak and two secondary peaks. On the basis of their ecological characteristice, the Hydromedusae, Siphonophores and Ctenophores found in the region investigated may be divided into the following ecological groups: estuarine group, neritic group and oceanic group. Their seasonal succession is correlated with the relative intensity of several water systems.

Occurrence and Identification of the Hydromedusae Sarsia tubulosa(Hydrozoa, Corynidae) in Chinese Coastal Waters

Sarsia tubulosa(M. Sars, 1835) belongs to the family Corynidae, and is mainly distributed in coastal boreal and arctic waters. During regular zooplankton sampling in a coastal artificial lake(Lake Fenghuang) near the northern Yellow Sea(36?55?N, 122?24?E) in May 2015, we found high densities of Sarsia sp. in the zooplankton samples. The mean density of the medusae was 50± 40 individuals m^(-3)(mean ± SD). These specimens were characterized by a long tube-like manubrium and were consistent with previous descriptions of S. tubulosa. Furthermore, a molecular phylogenetic analysis of the mitochondrial cytochrome c oxidase I subunit gene fragments revealed that these individuals clustered with S. tubulosa. Therefore, based on both morphological and molecular data, these specimens were identified as S. tubulosa. This report represents the first formal record of S. tubulosa in Chinese coastal waters, which extended its known geographical distribution.

Three new species of Genus Euphysora from China seas(Hydrozoa:Anthomedusae,Corymorphidae)

Three new species of Genus Euphysora (Hydrozoa: Anthomedusae, Corymorphidae ) from China seaswere described in great detail. All type specimens are deposited in the Department of Oceanography, Xiamen University.

Bacterial communities associated with hydromedusa Gonionemus vertens in diff erent regions in Chinese coastal waters

Bacteria communities in cnidarian jellyfi sh can be harmful to many important aquaculture species,as they can be key vectors of bacterial pathogens.However,our knowledge of bacterial communities associated with jellyfi sh in culture ponds and their potential roles in the regulation of aquaculture species remains unclear.In this study,sequencing based on the bacterial 16S rRNA gene was used to investigate the composition and variation of the bacterial communities associated with hydromedusa Gonionemus vertens in sea cucumber culture ponds and natural marine environment.The associated bacterial communities of G.vertens from the culture ponds in the Yellow Sea and Bohai Sea had signifi cantly diff erent compositions,when compared with those from ambient seawater environment.Furthermore,bacterial communities associated with G.vertens had similar diversity and composition in culture ponds and natural marine environment in the Yellow Sea.There were 31 unique bacterial biomarkers identifi ed in three locations.The major communities were highly abundant in Kiloniellales,Octadecabacter,Polynucleobacter,and Polaribacter,and are related to the environmental information processing.Pathogen candidates such as Vibrionales and Chlamydiales had notably low relative abundances(<1%).The venom of the jellyfi sh was considered responsible for damage to the aquaculture.This study provides important data to help assess the impact of cnidarians-associated bacterial communities on pond aquaculture and the infl uences on material cycling and energy fl ow in marine ecosystems.

Two new species of hydromedusa(Cnidaria)from the Leizhou Bay,the northern South China Sea

Two previously unknown species of hydromedusae,i.e.Bougainvillia leizhouensis Xu,Guo&Wang,sp.nov.and Octocannoides tetranema Xu,Guo&Wang,sp.nov.were found in plankton samples collected during oceanographic cruises along the Leizhou Bay of the northern South China Sea.All new species are described and illustrated here.Identification keys to the known species of genera Bougainvillia and Octocannoides,and the genera of family Octocannoididae are provided,respectively.In addition,the genus name Pedunculus Xu,Huang&Guo,2019 is preoccupied,and Stylogastria Xu,Huang&Guo,nom.nov.is proposed to replace it.All type specimens are deposited in the College of Ocean and Earth Sciences,Xiamen University.