One freshwater species of the genus Cyclidium, Cyclidiumsinicum spec. nov. (Protozoa; Ciliophora), with an improved diagnosis of the genus Cyclidium.

Xuming Pan,Weijie Mu,Ying Chen,Hui Chen,Chengdong Liang,Lijie Yu,Alan Warren,Chundi Wang

doi:10.1099/ijsem.0.001642

Abstract

The morphology and infraciliature of one freshwater ciliate, Cyclidium sinicum spec. nov., isolated from a farmland pond in Harbin, northeastern China, was investigated using living observation and silver staining methods. Cyclidium sinicum spec. nov. could be distinguished by the following features: body approximately 20-25×10-15 µm in vivo; buccal field about 45-50 % of body length; 11 somatic kineties; somatic kinety n terminating sub-caudally; two macronuclei and one micronucleus; M1 almost as long as M2; M2 triangle-shaped. The genus Cyclidium is re-defined as follows: body outline usually oval or elliptical, ventral side concave, dorsal side convex; single caudal cilium; contractile vacuole posterior terminal; adoral membranelles usually not separated; paroral membrane 'L'-shaped, with anterior end terminating at the level of anterior end of M1; somatic kineties longitudinally arranged and continuous. Phylogenetic trees based on the SSU rDNA sequences showed that C. sinicum spec. nov. clusters with the type species, Cyclidiumglaucoma, with full support. Cyclidium is not monophyletic with members of the clade of Cyclidium+Protocyclidium+Ancistrum+Boveria.

Highlights

Scuticociliates are common inhabitants of freshwater, brackish, and marine habitats (Budiño et al., 2011; Castro et al, 2014; Fan et al, 2011a, b; Foissner et al, 2014; Foissner & Wilbert, 1981; Lynn &Strüder-Kypke, 2005; Pan H. et al, 2015; Pan X. et al, 2013a, b, 2015a, b, 2016; Pan & Bullard, 2016; Song et al, 2002, 2003, 2009; Zhan et al, 2014)
Cyclidium sinicum spec. nov. is distinguished by the following features: body approximately 20–25 × 10–15 μm in vivo; buccal field about 45–50 % of body length; 11 somatic kineties; somatic kinety n terminating sub-caudally; two macronuclei and one micronucleus; M1 almost as long as M2; M2 triangle-shaped
The genus Cyclidium is re-defined as follows: body outline usually oval or elliptical, ventral side concave, dorsal side convex; single caudal cilium; contractile vacuole posterior terminal; adoral membranelles usually not separated; paroral membrane “L”-shaped, with anterior end terminating at the level of anterior end of M1; somatic kineties longitudinally arranged and continuous

Summary

Introduction

Scuticociliates are common inhabitants of freshwater, brackish, and marine habitats (Budiño et al., 2011; Castro et al, 2014; Fan et al, 2011a, b; Foissner et al, 2014; Foissner & Wilbert, 1981; Lynn &Strüder-Kypke, 2005; Pan H. et al, 2015; Pan X. et al, 2013a, b, 2015a, b, 2016; Pan & Bullard, 2016; Song et al, 2002, 2003, 2009; Zhan et al, 2014). The morphology and infraciliature of one freshwater ciliate, Cyclidium sinicum spec. Is distinguished by the following features: body approximately 20–25 × 10–15 μm in vivo; buccal field about 45–50 % of body length; 11 somatic kineties; somatic kinety n terminating sub-caudally; two macronuclei and one micronucleus; M1 almost as long as M2; M2 triangle-shaped.

Results

Conclusion