Morphology and Molecular Phylogeny of Two Little-Known Species of Loxodes, L. kahli Dragesco & Njiné, 1971 and L. rostrum Müller, 1786(Protist, Ciliophora, Karyorelictea)

The morphology and phylogeny of two little-known species, Loxodes kahli Dragesco & Njiné, 1971 and L. rostrum Müller, 1786, isolated from freshwater muddy sediments in China, were investigated based on live features, infraciliature, and small subunit ribosomal DNA(SSU rD NA) sequence data. Loxodes kahli is distinguished from its congeners mainly by the number and arrangement of macronuclei(6-17 in one row) and the number of right somatic ciliary rows(11-26). The Chinese populations of L. kahli also exhibit differences with other populations in terms of the body size and the number of right ciliary rows. The characteristics of L. rostrum are consistent with those of previous studies except for the number of right ciliary rows(9-10). The studied species were redefined based on the new information and previous descriptions. This study also gave a brief morphological summary of the species in the genus Loxodes by an identification key. SSU rDNA sequence-based phylogenetic analyses revealed that both species are grouped with their congeners, supporting the monophyly of the genus Loxodes.

Integrative studies on the taxonomy and molecular phylogeny of four new Pleuronema species(Protozoa,Ciliophora,Scuticociliatia)

The ciliate genus Pleuronema comprises approximately 30 nominal species and has been reported in freshwater,brackish water,and marine habitats.Nevertheless,recent studies have indicated that there might be a large undiscovered species diversity.In the present work,four new Pleuronema species,namely P.foissneri sp.nov.,P.parasmalli sp.nov.,P.parasalmastra sp.nov.,and P.paraorientale sp.nov.,collected from Shenzhen,southern China,was investigated using taxonomic methods.The diagnosis,description,comparisons with morphologically related species and detailed morphometric data are supplied for each.The small subunit ribosomal RNA(SSU rRNA)gene of the four new species is sequenced and their molecular phylogeny is analyzed.The SSU rRNA gene tree shows that Pleuronema is polyphyletic comprising several separate clades.All four new species cluster consistently with P.orientale KF206429,P.puytoraci KF840520 and P.setigerum FJ848874 within the core Pleuronematidae+Peniculistomatidae clade.Phylogenies of Pleuronematidae-related taxa are also discussed.

Doublets of the unicellular organism Euplotes vannus(Alveolata,Ciliophora,Euplotida):the morphogenetic patterns of the ciliary and nuclear apparatuses associated with cell division

Ciliated protists are one of the most diverse and highly differentiated group among unicellular organisms.Doublets occur in ciliates when two cells fuse into a single individual.Doublets contain two major cellular components(either cell in a doublet)and have traditionally been considered as developmental anomalies.Nevertheless,doublets can divide or even conjugate effectively,which may represent dispersal forms of the life stages.In addition,morphogenesis,as an important process in the life cycle,will provide important insights into the complex differentiation mechanism and various physiological phenomena.However,morphogenetic studies focusing on doublets of ciliates are very limited,which has become an obstacle to understand their complete life history.Here we isolated a doublet strain from the marine species Euplotes vannus(Müller,1786)Diesing,1850 and investigated its morphogenetic events during asexual reproduction.Our results indicate that:(1)the opisthe’s oral primordium develops de novo beneath the cortex;(2)the frontoventral and transverse cirral anlagen,cirrus I/1,and marginal anlagen in both dividers develop de novo separately;(3)the dorsal kinety anlagen,the three rightmost ones of which produce three caudal cirri for the proter,occur within the parental structures in the mid-body region;(4)the opisthe acquires two caudal cirri,one from the end of each two rightmost kineties;and(5)there are two macronuclei and one micronucleus in the doublet and they divide amitotically and mitotically,respectively.Finally,we speculate that this special differentiation may be an adaptive form to adverse environments.

Phylogeny of the anaerobic ciliate genus Sonderia(Protista:Ciliophora:Plagiopylea),including the description of three novel species and a brief revision of the genus

Anaerobic protists in general,and ciliates in particular,are important components of anoxic or hypoxic environments,however,their diversity remains underestimated.Sonderia is a poorly studied genus that is distributed worldwide and is commonly found in anaerobic environments.In the present study,the taxonomy and phylogeny of three new species,namely Sonderia aposinuata sp.nov.,Sonderia paramacrochilus sp.nov.and Sonderia steini sp.nov.,collected from China,were investigated based on microscopic observations and SSU rRNA gene sequencing methods.Sonderia aposinuata sp.nov.is diagnosed mainly by having a relatively large body size,a crescent-shaped oral opening,numerous slender extrusomes,one suture on the ventral side and two on the dorsal side,and a buccal cavity that occupies the anterior third of the cell.Sonderia paramacrochilus sp.nov.closely resembles S.macrochilus but differs mainly by its oral opening being located closer to the anterior cell margin and its spindle-shaped extrusomes.Sonderia steini sp.nov.is a freshwater species that can be recognized by its shallow buccal cavity,sparsely distributed rod-shaped extrusomes,and having 68–79 monokinetidal somatic kineties that form sutures on both sides of the body.Phylogenetic analyses based on small subunit ribosomal RNA(SSU rRNA)gene sequence data support the monophyly of the family Sonderiidae,however,Sonderia is paraphyletic.The genus Sonderia is briefly revised and a key to the identification of species belonging to this genus is supplied.