Two new species of flatworm, collected from a beach at eastern Shenzhen, China, were studied through an integrative approach by combining morphological, histological, histochemical (acetylcholinesterase, AChE), and molecular (18S r- DNA) data. These species belong to two genera of marine triclads, previously unrecorded from China, viz. Nerpa Marcus, 1948 and Paucumara Sluys, 1989. Nerpa fistulata Wang & Chen, sp. nov. is characterized by: transparent body; principally pentamerous intestine with three distinct commissures; two very large, prepharyngeal testis follicles; a semi-circular lens in each eye cup; a penis papilla provided with a chitinized, pointed stylet; lateral bursae communicating with the oviduct and opening ventrally to the exterior via a duct. Phylogenetically N. fistulata groups with one member of the family Bdellouridae. This new, Chinese species of Nerpa introduces a major geographic disjunction, as the type species N. evelinae was described from the bay of Santos, Brazil, so that the genus is now known from both Atlantic as well as Pacific coasts. The species Paucumara falcata Wang & Li, sp. nov. is characterized by: three distinct pale yellow transverse pigmentation bands on its dorsal side, between which some snowflake-like specks are randomly distributed, and a brown transverse band anteriorly to the eyes; 8–11 testicular follicles on either side of the body, the follicles extending from immediately behind the ovaries to half-way along the pharyngeal pocket; a musculo-parenchymatic organ with a sclerotic, curved tip projecting from the anterior wall of the male atrium, ventrally to the root of the penis papilla. Phylogenetically P. falcata groups with its congener P. trigonocephala, with the genus Paucumara forming the sister taxon of the genus Ectoplana. Comparison of the nerve structure of P. falcata, as revealed by AChE histochemistry, with that of eight other species of triclad suggested that the nervous system of marine planarians is simpler than that of species of freshwater planarians, but revealed also that the nerve structure is rather variable among species. The copulatory position exhibited by two partners in Paucumara falcata is remarkable in that they intertwine, with their heads pointing downwards and the tails pointing upwards, the entire process lasting about 10 min. Such a copulatory position has never before been reported for triclad flatworms.
The excellent wall condition is essential for fusion devices to generate reproducible high-parameter plasma. Wall conditioning techniques should be validated before applying on large fusion devices to reduce potential risk. Helimak, a toroidal steady state magnetic confinement device, was reassembled and upgraded to a technical validation platform for wall conditioning. A new control system has been developed to achieve the upgrade of Helimak. The control system is based on a distributed control architecture, which provides not only efficient development but also flexible control mechanisms. For each auxiliary subsystem, a corresponding local control module is developed to drive and control a variety of equipment. The control network ensures real-time transmitting of the parameters and data. A dedicated trigger network and timing control module can improve synchronization and real-time performance. Data acquisition system based on mature commercial busses provides sufficient data acquisition capabilities for diagnostic tools. The data management system uses MDSplus to provide convenient data access. An independent interlock and safety system is designed for comprehensive and reliable personal protection. After engineering commissioning, the Helimak has realized wall conditioning by electron cyclotron resonance heating (ECRH) plasma at different resonance positions. The flexibility of control systems allows the installation of more wall conditioning tools in the future that will provide the ability to validate combined wall conditioning techniques. Helimak will become a low-cost, reliable technology verification platform, which will help to achieve advanced scenarios in tokamak and stellarator.
In this contribution, feeding behaviour assays with the three species Paucumara falcata, Dugesia sp. and Girardia sp. were used to investigate the function of the pharynx during feeding and whether absence of feeding behaviour until full regeneration is a widespread phenomenon among planarians from different taxonomic groups. Our results showed that feeding behaviour of decapitated flatworms was inhibited. Intact worms responded only to pork liver pieces, but isolated pharynges were highly responsive to both pork liver pieces and pork liver extracts. After transverse cutting, the oral part of the isolated pharynx was responsive, while the aboral part showed no response to food items, suggesting that the oral portion of pharynx plays a crucial role during feeding.
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