title: Two New Genera of Planktonic Ciliates and Insights into the Evolution of the Family Strombidiidae (Protista, Ciliophora, Oligotrichia).
abstract: Oligotrich ciliates are common marine microplankters, but their biodiversity and evolutionary relationships have not been well-documented. Morphological descriptions and small subunit rRNA gene sequences of two new species representing two new strombidiid genera, Sinistrostrombidium cupiformum gen. nov., sp. nov. and Antestrombidium agathae gen. nov., sp. nov. are presented, and their taxonomy and molecular phylogeny are analyzed. Sinistrostrombidium gen. nov. is characterized by a sinistrally spiraled girdle kinety and a longitudinal ventral kinety. Antestrombidium gen. nov. is distinguished by tripartite somatic kineties (circular and ventral kineties plus dextrally spiraled girdle kinety). Sinistrostrombidium and Antestrombidium branched separately from one another in phylogenetic trees, clustering with different clades of strombidiids. The new genera added to the diversities of ciliary patterns and small subunit rRNA gene sequences in strombidiids leads to presentation of a new hypothesis about evolution of the 12 known strombidiid genera, based on ciliary pattern and partly supported by molecular evidence. In addition, our new morphological and molecular analyses support establishment of a new order Lynnellida ord. nov., characterized by an open adoral zone of membranelles without differentiation of anterior and ventral membranelles, for Lynnella, but we remain unable to assign the genus to a subclass with confidence.
authors.affiliation: Laboratory of Protozoology, Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, South China Normal University, Guangzhou, China; Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China; Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Science, Guangzhou, China.
authors.forename: Weiwei
authors.initials: W
authors.lastname: Liu
authors.affiliation: Laboratory of Protozoology, Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, South China Normal University, Guangzhou, China.
authors.forename: Zhenzhen
authors.initials: Z
authors.lastname: Yi
authors.affiliation: State Key Laboratory of Marine Environmental Science, Institute of Marine Microbes and Ecosphere, Xiamen University, Xiamen, China.
authors.forename: Dapeng
authors.initials: D
authors.lastname: Xu
authors.affiliation: Department of Biology, North Carolina Central University, Durham, United States of America.
authors.forename: John C
authors.initials: JC
authors.lastname: Clamp
authors.affiliation: Laboratory of Protozoology, Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, South China Normal University, Guangzhou, China.
authors.forename: Jiqiu
authors.initials: J
authors.lastname: Li
authors.affiliation: Laboratory of Protozoology, Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education, South China Normal University, Guangzhou, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Lin
authors.affiliation: Laboratory of Protozoology, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao, China.
authors.forename: Weibo
authors.initials: W
authors.lastname: Song
mesh_terms: D005075:Biological Evolution; D002681:China; D016798:Ciliophora / Q000145:classification* / Q000235:genetics; D020459:Genes, rRNA; D010802:Phylogeny; D010933:Plankton / Q000145:classification* / Q000235:genetics