Morphology of Cyclotrichium taniguchii sp nov and C. cyclokaryon with establishment of a new genus, Dicyclotrichium gen. nov (Ciliophora: Haptorida)

The morphology and infraciliature of two planktonic marine ciliates, Cyclotrichlum cyclokagon, type species of the genus and G taniguchii sp. nov. were investigated on live and protargol-impregnated specimens collected from the jiaozhou Bay at Qingdao, China. Based on the present as well as previous studies, an improved diagnosis for the poorly defined genus Cyclotrichlum is suggested: Didinildac with ovoid to barrel-shaped body; cell-surface densely ciliated except in the domed proboscis region; anterior ends of kinetics with long cilia forming one circumoral wreath of pectinelles; one circumoral kinety composed of a zig-zag structure; dorsal brushes absent. Cyclotrichlum taniguchii is distinguished from its congeners by the combination of the following features: ellipsoid body shape, marine habitat, details of ciliature, and lack of a posterior tuft. Based on the characters of the ciliary pattern, a new genus, Dicyclotrichium gen. nov., with the type species Dicyclotrichlum sphaericum comb. nov. is established. The new taxon differs from Cyclotrichlum by having two wreaths of pectinelles. Two known morphotypes are suggested to be assigned into this genus: Dicyclotrichium faurei comb. nov. [basionym: Askenasla faurei] and D. humills comb. nov. [basionym: Askenasia humills].