Some problems about identification of freshwater invertebrates(PROCEEDINGS, JSSZ SYMPOSIUM,2007)

Abstract

Difficulties of identification by using illustrated book and dichotomous key, and problems of tabulating identified taxa are discussed. In many cases, information about diagnoses which discriminate a species from its relatives is not provided well in illustrated books. In dichotomous keys, on the other hand, discriminating characters are summarized tersely for each species but diagnostic characters tend to be subtle and judgment of them are often puzzling for beginner taxonomists. Use of matrix (or tabular) key, which avoid these difficulties, is recom mended. In the case that identification of a specimen does not reach species level, it is placed in a higher taxonomic group, which may contain various entities. Annotations for higher taxa may reduce problems caused by heteroge neity of higher groups.