碩士 / 國立海洋大學 / 水產養殖學系 / 87 / Most taxonomic studies of mollusks rely heavily on morphological characters. However,the shape and color pattern of many shellfishes is irregular and depends on the type of substrate on which it is grown,as well as on the degree of crowding. Structural characteristics of molluscan sperm are often used to define phylogenetic relationships and cladistic tree,and are especially useful when comparing closely related species. The structure of the sperm of 2 species from two families of archaeogastropod (Trochidae,Turbinidae) and three families of bivalvia (Veneroida,Mytilidae,Arcidae), has been examined with electron microscopy. A comparative study of sperm ultrastructure from these ecologically and economically important order of Taiwan mollusks has revealed significant differences between taxa.Similarly sperm morphology can be used to differentiate between archaeogastropod . The sperm of the Trochidae and Turbinidae all have a head which is cylindrical The nucleus, which is cylindrical has a narrow anterior fossa. The acrosome,which constitutes 40-50% of the total length of the sperm head and has a narrow anterior canal containing an axial rod. The acrosomal contents may or may not be differentiated. The overall ultrastructure of sperm from Trochidae , Turbinidae corresponds to the primitive type of externally fertilizing archaeogastropods, and is similar in appearance to those of investigated Haliotids. However, each of these can be differentiated by slight details.Most bivalves sperm are of the aquasperm type (general features:conical acrosome,nucleus usually short, midpiece consisting of a ring of round mitochondria surrounding the centrioles,single simple flagellum). Several principle sperm morphologies can be recognized in the Veneroida,these correlating to varying degrees of precision with groups of superfamilies.The results of the present study strongly support the suggestions that sperm ultrastructure is of great potential use as a taxonomic and may be a phylogenic criterion in the mollusks.
| Identifer | oai:union.ndltd.org:TW/087NTOU0086002 |
| Date | January 1999 |
| Creators | Chen, Ping-Chi, 陳平基 |
| Contributors | Gwo, Jin-Chywan, 郭金泉 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 58 |
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