Verbruggen H., De Clerck O. & Coppejans E. (2005)
Deviant segments hamper a morphometric approach towards Halimeda taxonomy
Cryptogamie Algologie 29: 259-274


Traditional taxonomy of the segmented green algal genus Halimeda is largely based on descriptive expressions of thallus habit, segment shape and anatomical structures. In the course of the last decade, molecular phylogenetic studies have revealed non-monophyly and cryptic diversity in several species. In an attempt to tackle the taxonomic problems that were raised by these molecular studies, a combined molecular and morphometric method was developed. In this study, a morphometric pilot data set is explored. This resulted in the discovery of segments aberrant in morphology and/or anatomy. These are primarily apical and non-calcified segments, and segments from the basal part of the algal body. To answer the question whether incorporation of comparison of discriminant analyses that included and excluded deviant segments demonstrated the negative influence of such segments on the taxonomic power of the data. Omitting non-calcified and apical segments and segments from the basal thallus region yielded the same results as the exclusion of all deviant segments, irrespective of their location in the algal body. This result permits a simple recommendation towards precluding these types of segments from further studies.

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