Phylogenetic morphometrics (I): the use of landmark data in a phylogenetic framework

Authors

  • Santiago A. Catalano,

    Corresponding author
    1. Consejo Nacional de Investigaciones Científicas y Técnicas
    2. Fundación Miguel Lillo, Miguel Lillo 251, 4000 S.M. de Tucumán, Argentina
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  • Pablo A. Goloboff,

    1. Consejo Nacional de Investigaciones Científicas y Técnicas
    2. Facultad de Ciencias Naturales e Instituto Miguel Lillo, Miguel Lillo 205, 4000 S.M. de Tucumán, Argentina
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  • Norberto P. Giannini

    1. Consejo Nacional de Investigaciones Científicas y Técnicas
    2. Programa de Investigaciones de Diversidad Biológica Argentina, Facultad de Ciencias Naturales, Miguel Lillo 205, 4000 S.M. de Tucumán, Argentina
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Corresponding author:
E-mail address:sacatalano@gmail.com

Abstract

A method for the direct use of aligned landmark data (2D or 3D coordinates of comparable points) in phylogenetic analysis is described. The approach is based on finding, for each of the landmark points, the ancestral positions that minimize the distance between the ancestor/descendant points along the tree. Doing so amounts to maximizing the degree to which similar positions of the landmarks in different taxa can be accounted for by common ancestry, i.e. parsimony. This method requires no transformation of the aligned data or the results: the data themselves are the x, y, z coordinates of the landmarks, and the output of mapping a character onto a given tree is the x, y, z coordinates for the hypothetical ancestors. In the special case of collinear points, the results are identical to those of optimization of (continuous) additive characters.

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