Species Composition, Season Dynamic And Molecular Systematic Analysis Of Marine Fish Cestodes In Minnan-Taiwan Bank

Species composition of marine fish cestodes and seasonal dynamic of 2 newly identified cestodes in Minnan-Taiwan Bank along the coastal area of Xiamen and Dongshan were investigated from October, 2004 to October, 2006.88 species of mareine fish and 456 individuals were examined in this survey. Among them, 12 species were found to be cestode-parasiting. All of those cestode-inhibiting fishes are elasmobranchs, except Psenopsis anomela. 27 species of cestode in total were obtained in this study, which can be allocated to 5 orders, 11 families, and 17 genera. Among those, 14 species can be positioned to actual species. On the other hand, there were 24 species that can only be allocated to genus, including 5 new species, 10 unidentified species, and 2 domestically first reported species (i.e., Echinobothrium longicolle Southwell, 1925; and Anteropora japonica Yamaguti, 1934). Notably, 3 species of Diphyllidea were firstly reported in China in this survey, furnishing the blankness Diphyllidean study and enhancing the diversity of bio-resources in China.10 species of cestodes in total, including 5 new species, 3 unidentified species, and two domestically first reported species were described in this research:1. Echinobothrium longicolle Southwell, 19252. Echinobothrium zugeimensis n. sp.3. Macrobothridium sinensis n. sp.4. Pterobothrium sp.5. Anteropora japonica Yamaguti, 19346. Yorkeria xiamenensis n. sp.7. Oncoboththrium parva n. sp.8. Carpobothrium sp.9. Scalithrium sp.10. Flabellobothrium parva n. g. n. sp.The seasonal dynamic of Macrobothridium sinensis n. sp. and Biotobothrium platyrhina in Platyrhina sinesis showed that the variety of monthly infection rate of these two species presenting in a complementary pattern, i.e., the percentage of co-occurance of these two cestodes is rather low, inferring that competition among these two species in the gut lumen of Platyrhina sinesis might exist. In addition, the transformation of monthly infection rate of these two species was somehow restricted by infection rate, thus the variety of quantity exhibited in complementary pattern, too.Based on the molecular techniques, interrelationship of partial marine fish cestodes in Minnan-Taiwan Bank was examined in this study. By analysing the sequences of 16S rRNA of 19 species from 5 orders and the sequences of 18S rRNA of 5 Lecanicephalidean species, phylogenetic trees were constructed. The results showed that each branch of the tree was constructed by species from one order, supporting the ordinal status of classical taxonomy. Besides, the transformation of bipartite scolex to tetrapartite scolex is appropriate to species-evolutionary law in which morphology of an individual becomes more complicated with the progression. Furthermore, the phylogenetic tree resulted not only corroborates the systematic treatment of Macrobothridium and Echinobothrium in order Diphyllidea, but also verifies the taxonomic position of Scalithrium and Anteropora which are originated of Tetraphyllidea and Lecanicephalidea, relatively.