The Ultrastructure of Adhensive organs in Pseudecheneis with Comments on Its Signifieance
Zhou Wei;Liu Desheng Kunming Institute of zoology, the Chinese Academy of Sciences
This paper deals with the ultrastructure of adhensive organs in the genus Psendecheneis (Siluriformes:Sisoridae). Adhensive organs in Pseudecheneis include two parts, one is laminated adhensive padon ventral sur-face of the outermost ray of the paired fins, the other one is laminated thoracie adhensive organ. The basicalultrastructure of both organs is same, i. e. epidermal surface is covered with slender, posteriorlydirected,hookshaped projects. However, there is difference between the laminae of the pelvic fin and of the thoracieadhensive organ on the ultrastrueture in Psendecheneis. There are ringshaped structure along front edge at ev-ery lamina of the thoracic adhensive organ, and there are none at laminae of the pelvic fin. The ultrastructuresdemonstrated above are conformed in the genus. Specialy, the fact that there are ringshaped structure atthoracic adhensive organ in all species may be a clue which implies all species originated from one ancestor. Thisidea supports the former work in which all species with tranverse laminae thoracie adhensive or-gan, but usedto be in different genera, had been classified into Pseudecheneis. Hookshaped projects are also found atepidermal surface near the thoracic organ. Most of sisorid fishes are bottom-dwelling, some of them have nonetaking-shaped thoracic organ. Does thcir cpidermal surface of thorax occur some changes, like hookshapedprojects? This is a very interesting problem. This supposal can be examined in the future work.