Diversity And Distribution Of The Nematocyst From Jellyfish

Jellyfish,classified as Cnidarian,is an important taxon of zooplankton,and distributes all over the world.The nematocysts located in the epithelial stinging cells(cnidocytes)of all cnidarians are an important taxonomical tool for the classification of the Cnidaria.Nematocysts can discharge under proper stimulations,exhibiting the significant diversity.Researches focused on nematocyst in domestic were rare and most studies are limited to light conditions.Therefore,it is necessary to study the morphological structure and classification of nematocyst.In this study,we investigated 30 species of jellyfish collected from Xiamen offshore water using light microscope and scanning electron microscope.The main results and conclusions are as follows:1)We identified 17 repotred types of nematocysts from 30 species of jellyfish,including atrichous isorhizas,basitrichous isorhizas,merotrichous isorhiza,desmoneme,haploneme,anisorhizas,microbasic laevis mastigophore,microbasic mastigophore,microbasic spin-mastigophore,macrobasic mastigophore,microbasic eurytele,heterotrichous microbasic eurytele,homotrichous microbasic eurytele,microbasic amastigophore,basidilatares,stenotele.Nematocysts are conspicuously diverse.2)Types of nematocyst in different jellyfish showed distinct.The subclass Narcomedusae have only one type of nematocyst(atrichous isorhizas).The subclass Tachymedusae have four types of nematocyst,including atrichous isorhizas,heterotrichous microbasic eurytele,microbasic spin-mastigophore.The subclass Anthmedusae of nematocyst have ten types of nematocyst,including haploneme,anisorhizas,desmoneme,basidilatares,stenotele,microbasicamastigophore,amastigophores,microbasic spin-mastigophore,atrichous isorhizas,homotrichous microbasic eurytele.The subclass Leptomedusae have six types of nematocyst,including basitrichous isorhizas,merotrichous isorhiza,microbasic eurytele,microbasic spin-mastigophore,atrichous,isorhizas,microbasic mastigophore.The subclass Siphonphorae have three types of nematocyst,including microbasic laevis mastigophore,desmoneme,haploneme.3).Distribution of nematocyst in the jellyfish exhibit a certain patterns.Overall,the nematocyst locate in the tentacles,lips,oral tentacles and exumbrella.Distribution of different tissue presents unique patterns.For example,there are three types of the distribution patterns in the tentacles,1)the nematocysts have a small number in the tentacles;2)form ball of nematocysts in the tentacles;3)large number of nematocysts distribute on the surface of tentacles.The number of nematocyst of the tentacles compared to nematocyst on the oral tentacles and lips.Overall,nematocysts on the exumbrella show scattered distribution or form small collection.Distribution of nematocyst in the subclass Siphonphorae is relatively special.In this study,we observed that tentacles on single vegetation period also have nematocyst,different types of nematocyst exhibitted significantly distinct distribution patterns.