Analysis of shape variation of the third upper molar in the rock vole Alticola (Cricetidae) by geometric morphometrics

摘要

The shape variation of M~3 talon in five tara of the genus Alticola is analyzed numerically by using x, y-coordinates of landmarks set on tips of the tooth inlands and outfolds instead of standard measurements. The original data are processed by methods of routine multivariate statistics and geometric morphometrics. The shape transformations of the talon might be considered as two independent constituents: longitudinal (correlated with tooth size) and transversal displacements of the fold tips. It means that complication of the tooth occlusial surface by transformations of its folds does not correlate with the tooth elongation. The multiple regression analysis revealed several groups of specimens differing in shape of the talon. The discriminant analysis of Alticola tara appears to provide the greated resolution, when landmark coordinates are used directly as characters, than relative warps obtained on the basis of the same coordinates by the method of geometric morphometrics.