| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1997: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1996: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
Triggerfishes of the family Balistidae are found mainly in tropical regions in the Indo-Pacific and Atlantic. The Balistidae are composed of 11 genera and 30 species. Systematic studies of this family were made by Matsuura (19780) and phylogenetic relationships were published by Matsuura (1979) and Tyler (1980). There remaine no large problems in the taxonomy of adult triggerfishes. However, as in many cases of other teleostean fishes, larvae of triggerfishes are difficult to be identified to species or even to generic level because it is not easy to obtain adequate materials including series from early developmental stage to young. Thus, the main purpose of this study is to describe diagnostic characters of triggerfish larvae based on many individuals being now available at museums and fisheries institutions.
The detailed examinations of many triggerfish larvae and adults led to a conclusion that they can be identified by using combinations of meristic characters of dorsal-fin rays, anal-fin rays, pectoral-fin rays, longitudinal scale rows, and head scales. In many cases color patterns of larvae and young are helpful to identify them to generic level and frequently to species level. Osteological examinations of larvae and adults show that the genus Xenobalistes is first separated phylogenetically from all other genera. In the remaining 10 genera, Canthidermis is differentiated from the others, then Xanthichthys, Rhinecanthus, and Balistapus are separated from the others. The most derived genus is considered to be Abalistes.
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