Biodiversity of freshwater ciliates(Protista,Ciliophora)in the Lake Weishan Wetland,China:the state of the

Ciliates are core components of the structure of and function of aquatic microbial food webs.They play an essential role in the energy flow and material circulation within aquatic ecosystems.However,studies on the taxonomy and biodiversity of freshwater ciliates,especially those in wetlands in China are limited.To address this issue,a project to investigate the freshwater ciliates of the Lake Weishan Wetland,Shandong Province,commenced in 2019.Here,we summarize our findings to date on the diversity of ciliates.A total of 187 ciliate species have been found,94 of which are identified to species-level,87 to genus-level,and six to family-level.These species show a high morphological diversity and represent five classes,i.e.,Heterotrichea,Litostomatea,Prostomatea,Oligohymenophorea,and Spirotrichea.The largest number of species documented are oligohymenophoreans.A comprehensive database of these ciliates,including morphological data,gene sequences,microscope slide specimens and a DNA bank,has been established.In the present study,we provide an annotated checklist of retrieved ciliates as well as information on the sequences of published species.Most of these species are recorded in China for the first time and more than 20%are tentatively identified as new to science.Additionally,an investigation of environmental DNA revealed that the ciliate species diversity in Lake Weishan Wetland is higher than previously supposed.

Ontogenesis and systematic position of a new hypotrichous ciliate,Chaetospira sinica sp.nov.,with an improved diagnosis of the poorly defined family Chaetospiridae Jankowski,1985(Protozoa,Ciliophora,Hypotrichia)

Ciliates are unique single-celled organisms that play important roles in ecological,environmental,evolutionary,and ontogenetic research.In the present study,phylogenetic analyses based on 18S rRNA gene sequence data reveal that Chaetospira sinica sp.nov.clusters with Stichotricha aculeata with strong to full support(97%ML,1.00 BI),but is not closely related to members of Spirofilidae Gelei,1929 to which Chaetospira and Stichotricha have previously been assigned.Phylogenetic analyses,together with morphological and morphogenetic data from Chaetospira sinica sp.nov.,support the validity of family Chaetospiridae Jankowski,1985.Chaetospira and Stichotricha are here assigned to the family Chaetospiridae,the improved diagnosis of which is as follows:non-dorsomarginalian Hypotrichia with flask-shaped body;oral region extending along narrow anterior neck region;lorica usually present;two ventral and two marginal cirral rows,all distinctly spiraled or obliquely curved;pretransverse and transverse cirri absent.The basic morphogenetic features in C.sinica sp.nov.can be summarized as:(1)the oral primordium for the opisthe develops de novo and the parental adoral zone is completely retained by the proter;(2)all ventral cirral anlagen and marginal anlagen developed intrakinetally;(3)three dorsal kineties anlagen formed intrakinetally in each daughter cell;and(4)macronuclear nodules fuse into a single mass.Exconjugant cells were also isolated and their morphologic and molecular data are provided.