Studies On The Neobenedenia (Monogenea: Capsalidae) From Cultured Marine Fishes By Numerical Taxonomy And Molecular Analysis

Studies on the Neobenedenia (Monogenea: Capsalidae)from cultured marine fishes by numerical taxonomy andmolecular analysisAbstractParasitosis by the monogenean Neobenedenia has frequenily occurred in Fujian fishforing net-cage in the recent years. The tremendous threat to the health of culturedmarine fishes is indicated by its low host specificity wide distribution, and ability to causemortality due to heavy infection. The parasites were studied by following methods fmorphological observation and measurement, numerical taxonomy random amPlifiedpolpoorphic DNA (MD) and the 28S rDNA gene sequence analysis in the presentpaPer1. Through light microscope examination, most of the parasites on Seriola dumeriliXisso cultuTed in Xiamen were similar to Neobenedenia girellae Hargis in body shaPe,comparable measurements and possessing indented testes; Some of them, with wide andround body and prominelltly large anerior hamulus, aPpeared to be N melleni MacCallum,Bllt these feamres on other specimens were not such evideflt. The parasites onPseudosciaena crocea Xichardson in Putian and Lianjiang and on Nibea miichthioidesChu, Lo et Wu in Xiaxnen looked like N melleni according to the taxonomy of YamagUti(1963).2. Five species of Neobenedenia (N melleni, N girellae, N parg'Ueraensis Dyer,Wlliams and Bunkley-Wl1iams, N adenea Meserve and N isabellae Meserve) werestudied by numerical taxonomy based on l2 morphometric measurements. PrincipalcomPonent analysis (PCA) showed that the haPtor breadth and length, total length,maximum breadth, anterior haxnulus length, anterior attachment organs breadth andphM breadth might play imPortant roles in the classification of Neobenedenia. Theresult of hierarchica cluster analysis supports that species Nmelleni and Ngirellae areclosely related.3. The polyTnorphism of genomic DNA of N melleni, parasitized on the marine fishes,3AbstractS. dumerili, A. jaPonicus and P. crocea, cultWed in Xiamen, Pniian and Lianjiang ofFujian province were analyZed by RAPD. The results of 0.073~0.154 genetic differencesuggested that N melleni has vallation on the genetic level. The genetic distance (0.073)betWeen the Nmelleni col1ected from S. dumerili and A. jaPonicus in Xiamen was lowerthan that (0.094) betWeen the specimens from P. crocea in Lianjinag and Putian region.Furthermore, the great genetic similarity index (83. 1%~94.7%) indicated that there is littleobvious genetic differentaton betWeen N girellae and N melleni.4. 350bp of 28S MA fragments were obtained by Polamerrase Chain Reaction (PCR)and then sequenced for the closely related species, N girellae and N melleni, to test thehyPothesis that they are synOnwized. Also included fOr comPedson were othermorpho1ogically distinct sPecies within the genus, naxnely Benedenia luijani, B. rohde andB. seriolae. There was only 0.3% difference betWeen N girellae and N melleni, whereasthe intrasPecific divergence of N melleni was 0.59%. Meanwhi1e, the interspecificdifference among the B. luijani, B. roh de and B. serioIae were 2.08%~11.73%. Based onthe above genetic results and the morphological study, it is proposed that N girella and Nmelleni rePresent a single species.Furthermore, U'PGMA and MP molecular phylogenetic trees of 12monopisthocotyleans were constrUcted and proved to be consistent with the pologenybased on morphology HoweveT, the results of these tWo methods had difference in therelationships of families: ((CaPsalidae, Monocotylidae), Udone1lidae) from MP analysiswhi1e ((CaPsalidae, Udonellidae), Monocotylidae) from UPGMA analysis and the latterwas supported by higher bootstraP value.