From oral structure to molecular evidence:new insights into the evolutionary phylogeny of the ciliate order Sessilida(Protista,Ciliophora),with the establishment of two new families and new contributions to the poorly studied family Vaginicolidae  

作　　者：Borong Lu Xiaozhong Hu Alan Warren Weibo Song Ying Yan 

机构地区：[1]Institute of Evolution&Marine Biodiversity,Ocean University of China,Qingdao,266003,China [2]College of Fisheries,Ocean University of China,Qingdao,266003,China [3]Department of Life Sciences,Natural History Museum,London,SW75BD,UK [4]Laoshan Laboratory,Qingdao,266237,China

出　　处：《Science China(Life Sciences)》2023年第7期1535-1553,共19页中国科学（生命科学英文版）

基　　金：supported by the Laoshan Laboratory(LSKJ202203201);the National Natural Science Foundation of China(32030015,41976086,32270558,32111530116);Young Taishan Scholar Program of Shandong Province(tsqn202103037);the Fundamental Research Funds for the Central Universities(202141007);the China Postdoctoral Science Foundation(2021M703037)。

摘　　要：Ciliated protists represent one of the most primitive and diverse lineages of eukaryotes,with nuclear dimorphism,a distinctive sexual process(conjugation),and extensive genome rearrangements.Among divergent ciliate lineages,the peritrich order Sessilida includes members with a colonial lifestyle,which may hint to an independent evolutionary attempt for multicellularity,although they are still single-celled organisms.To date,the evolution and phylogeny of this group are still far from clear,in part due to the paucity of molecular and/or morphological data for many taxa.In this study,we extend taxon sampling of a loricate group of sessilids by obtaining 69 new r DNA(SSU r DNA,ITS1-5.8S rDNA-ITS2,and LSU r DNA)sequences from 20 wellcharacterized representative species and analyze the phylogenetic relationships within Sessilida.The main findings are:(i)the genera Rhabdostyla and Campanella each represents a unique taxon at family level,supporting the establishment of two new families,i.e.,Rhabdostylidae n.fam.and Campanellidae n.fam.,respectively,the former being sister to a morphologically heterogeneous clade comprising Astylozoidae and several incertae sedis species and the latter occupying the basal position within the Sessilida clade;(ii)the structure of infundibular polykinety 3 is likely to be a phylogenetically informative character for resolving evolutionary relationships among sessilids;(iii)differences between sparsely and the densely arranged silverline systems could be a suprageneric taxonomic character;(iv)the monophyly of Vaginicolidae is confirmed,which is consistent with its specialized morphology,i.e.,the possession of a typical peritrich lorica which might be an apomorphy for this group;(v)within Vaginicolidae,the monotypic Cothurniopsis sensu Stokes,1893 is a synonym of Cothurnia Ehrenberg,1831,and a new combination is created,i.e.,Cothurnia valvata nov.comb.;(vi)Vaginicola sensu lato comprises at least two distinctly divergent clades,one affiliated with Thuricola and the other with a systematicall

关 键 词：evolutionary hypotheses new families peritrich ciliates PHYLOGENY PROTIST 

分 类 号：Q959.11[生物学—动物学]