Frontiers in Microbiology | www.frontiersin.org 1 July 2021 | Volume 12 | Article 718757 ORIGINAL RESEARCH published: 30 July 2021 doi: 10.3389/fmicb.2021.718757 Edited by: Weiwei Liu, South China Sea Institute of Oceanology, Chinese Academy of Sciences (CAS), China Reviewed by: Igor Dovgal, A.O. Kovalevsky Institute of Marine Biological Research, Russia Laura Utz, Pontifical Catholic University of Rio Grande do Sul, Brazil *Correspondence: Lifang Li qd_liliy@sina.com Chundi Wang chundiwang102@foxmail.com † These authors have contributed equally to this work Specialty section: This article was submitted to Aquatic Microbiology, a section of the journal Frontiers in Microbiology Received: 01 June 2021 Accepted: 06 July 2021 Published: 30 July 2021 Citation: Wang Z, Wu T, Lu B, Chi Y, Zhang X, Al-Farraj SA, Song W, Warren A, Li L and Wang C (2021) Integrative Studies on a New Ciliate Campanella sinica n. sp. (Protista, Ciliophora, Peritrichia) Based on the Morphological and Molecular Data, With Notes on the Phylogeny and Systematics of the Family Epistylididae. Front. Microbiol. 12:718757. doi: 10.3389/fmicb.2021.718757 Integrative Studies on a New Ciliate Campanella sinica n. sp. (Protista, Ciliophora, Peritrichia) Based on the Morphological and Molecular Data, With Notes on the Phylogeny and Systematics of the Family Epistylididae Zhe Wang 1,2† , Tong Wu 2† , Borong Lu 2 , Yong Chi 2 , Xue Zhang 2 , Saleh A. Al-Farraj 3 , Weibo Song 1,2,4 , Alan Warren 5 , Lifang Li 1 * and Chundi Wang 1 * 1 Marine College, Shandong University, Weihai, China, 2 Key Laboratory of Mariculture, Ministry of Education, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China, 3 Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia, 4 Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China, 5 Department of Life Sciences, Natural History Museum, London, United Kingdom During an investigation on freshwater peritrichs, a new colonial sessilid ciliate, Campanella sinica n. sp., was isolated from aquatic plants in an artificial freshwater pond in Qingdao, China. Specimen observations of this species were performed both in vivo and using silver staining. C. sinica n. sp. is characterized by the appearance of the mature colony, which is up to 2 cm high and contains more than 1,000 zooids, the asymmetric horn- shaped zooids, strongly everted and multi-layered peristomial lip, the slightly convex peristomial disc, and the well-developed haplokinety and polykinety, which make more than four circuits of the peristome before descending into the infundibulum. The small subunit ribosomal DNA (SSU rDNA), 5.8s rDNA and its flank internal transcribed spacers (ITS1-5.8s rDNA-ITS2), and large subunit ribosomal DNA (LSU rDNA) are sequenced and used for phylogenetic analyses which reveal that the family Epistylididae Kahl, 1933 is non-monophyletic whereas the genus Campanella is monophyletic and nests within the basal clade of the sessilids. The integrative results support the assertion that the genus Campanella represents a separate lineage from other epistylidids, suggesting a further revision of the family Epistylididae is needed. We revise Campanella including the transfer into this genus of a taxon formerly assigned to Epistylis, which we raise to species rank, i.e., Campanella ovata (Nenninger, 1948) n. grad. & n. comb. (original combination Epistylis purneri f. ovata Nenninger, 1948). In addition, we provide a key to the identification of the species of Campanella. Keywords: rDNA sequences, morphology, peritrichs, sessilid ciliate, phylogenetic analyses