The morphology and morphogenesis of a marine ciliate, Epiclintes auricularis rarisetus nov. sspec. (Ciliophora, Epiclintidae), from the Yellow Sea

Abstract

The morphology and morphogenesis of a marine ciliate, Epiclintes auricularis rarisetus nov. sspec., collected from Qingdao, northern China were studied on live and protargol-impregnated specimens. This isolate can be recognized by its elongate, contractile and tripartite body with a size of 200-400×20-40 μm in vivo, about 30 ventrally located adoral membranelles, short undulating membranes, 2-3 frontal and 10-18 transverse cirri as well as 8-9 fronto-midventral rows, 22-31 left and 35-54 right marginal cirri, but no caudal cirri, invariably 3 dorsal kineties, of which kineties 1 and 3 link together anteriorly, 24-70 macronuclear nodules, marine habitat, and contribution of almost all frontal-midventral transverse cirral anlagen (FVT anlagen) to the formation of fronto-midventral rows. In its divisional morphogenesis, this species demonstrates some features rarely if ever found in any other urostyloids, e.g. partial replacement of the old adoral zone of membranelles, de novo formation of the oral primordium and the anlagen for marginal rows and dorsal kineties, contribution of almost all FVT anlagen to the transverse cirri, lack of frontoterminal cirri. In addition, its morphogenesis appears to differ in detail from that of E. auricularis auricularis nov. stat., based on published data. These remarkable morphogenetic traits of Epiclintes suggests a questionable systematic position for this genus in the Urostyloidea, therefore, further researches are urgently needed.