Biodiversity Of Marine Scuticociliates And Hymenostomatids (protozoa: Ciliophora)

Ciliates, as the most advanced heterotrophic protist, are the essential component of the food web marine ecosystem and plays an important role in the transfer of the productivity. In aquaculture waters, ciliates often act as harmful or even deathful pathogens and cause serious damage to the industry. In the fields, such as individual development and cytology, ciliates can be used as model organisms due to their short reproduction period and highly specialized organelles. But now the problem is highlighted: the entire diversity of this group is still unclear, and a large number of known species lack investigations basing on modern methods and thus are poorly defined. This situation causes a lot of inconveniences to the related researches as well as to the systematics.Aiming to solve the problem mentioned above, founded by the Natural Science Foundation of China, morphological and faunistic studies on free living ciliates in the coastal waters off Yellow Sea, Bohai Sea and South China Sea (including all kinds of habitats: sandy beach, openning water, tidal area, mari-cultural ponds etc.) were carried out during 2006-2010. As the result, 30 species belonging to 25 genera were collected and then studied using modern methods (living observations, protargol impregnation and silver carbonate impregnation methods). The achievements are summarized as follows:1. Wilbertia Fan et al., 2009. According to the infraciliature, it was classified to the Family Eurystomatidae. The diagnose for this genus is as followings: Eurystomatidae with sculptured, dorso-ventrally flattened body and dominant buccal field, which is almost completely enclosed by the highly developed PM; three long membranelles arranged in parallel; M1 and M2 multiple rowed, M1 well developed, M3 small; reticulate silverline system.2. Falcicyclidium nov. gen. Cyclidiid with dorsoventrally flattened body, hook-like (falciform) paroral membrane, paroral membrane anteriorly starting below the level of anterior end of membranelle 1 and multiple caudal cilia. Somatic kineties straight, with continuous kinetids.3. Cyclidium Ehrenberg, 1838Based the morphology and infraciliature of the genus type and related genera, a new diagnosis was given: Cyclidiidae with cylinder or drop-shaped body, single caudal cilium. Paraoral membrane L-shaped and anteriorly starting at the same level with membranelle 1. Somatic kineties straight, with continuous kinetids. Argyrome without secondary silverline meridian.4. Pseudoplatynematum Bock, 1952The genus has never been restudied since it was established, a new diagnosis was provided according to both living morphology and infraciliature: Body dorsoventrally flattened; cell surface conspicuously strengthened; thorn-like spines usually present; oral field subapically positioned; Loxocephalus-like oral structure; postoral kineties and extrusomes present; single caudal cilium; marine habitat. A Platynematum species was combinated: Pseudoplatynematum denticulatum (Kahl, 1933) nov. comb.5. Nine new species were describedBased on the detailed living morphology, infraciliature and comparison with known species, 9 new forms were founded and described: Wilbertia typica, Falcicyclidium fangi, Falcicyclidium atractodes, Sathrophilus planus, Pseudoplatynematum dengi, Uronema heteromarinum, Paratetrahymena parawassi, Frontonia magna, Frontonia mengi. 6. Description of psammophilic scuticociliatesEight scuticociliates Wilbertia typica, Falcicyclidium fangi, Falcicyclidium atractodes, Cristigera media, Histiobalantium marinum, Sathrophilus planus, Pseudoplatynematum dengi, P. denticulatum, which can be found only in sand were described. Several morphology characters were in common among this group: pellicle firm and tenacious, sometimes armored and forming ridges or even spines; body flattened with stiff cilia.7. Redescription of 20 known speciesBased on new populations, additional living and infraciliature information of the following 20 known species were afforded: Cyclidium varibonneti, Protocyclidium. cf. citrullus, Cristigera media, Pleuronema setigerum, Histiobalantium marinum, Sathrophilus holtae, Biggaria bermudensis, Uronema marinum, Metanophrys sinensis, Paranophrys magna, Mesanophrys carcini, Parauronema longum, Porpostoma notata, Philaster hiatti, Cohnilembus verminus, Miamiensis avidus, Uronemella parafilificum, Glauconema trihymene, Dexiostoma campyla, Glaucoma chattoni. Infraciliature of several species among these known form were firstly reported here.