形態空間解析による生物の形態的多様性の研究(<特集>生物多様性と古生物学)

抄録

Morphospaces are geometric spaces in which a particular organic form can be plotted with reference axes chosen to represent morphological parameters. The amount of the morphospace occupied by a taxonomic group provides a reliable assessment of morphological diversity of the group. Two types of parametric morphospaces have seen applications to analyses of morphological variation within a body plan; theoretical and empirical. Theoretical morphospaces are constructed on the basis of parameters of a geometric model of form which are a priori defined without the organisms being studied. The theoretical morphospaces have been used to document the range of actual forms of organisms as a subset of the forms that are theoretically possible but may be nonexistent. Empirical morphospaces, on the other hand, are produced with actual measurement data typically using such ordination techniques as principal components analysis and canonical variates analysis. A complex structure lacking simple geometry such as coiling or branching can be accommodated in an empirical morphospace. The morphospace concept has been extended to include discrete categories based on qualitative characters. The entire set of the combinations of the characters defines a hyperspace which is depicted as a table or tree. This type of morphospace, or design space, is applicable to a broad range of taxa with distinct body plans. There may be a great utility in morphospace for developing comprehensive collections on morphological information such as morphological databases.