Cladistic analysis

Cladistic analyses suggest that vertebrates evolved from a common ancestor of chordates through a stepwise increase in complexity of the body plan. This process involved the appearance of a number of vertebrate innovations both at an anatomical and a molecular level (Shimeld and Holland, 2000). Morphologically... 

Certain results of cladistic analyses suggest that the Mol-luginaceae and Caryophyllaceae are not closely related, but are relatively advanced and derived from betalain-containing... 

All morphological cladistic analyses have identified (or, more correctly, assumed) the sister-group of the seed-plants to be at least one progymnosperm. Where multiple progymnosperms have been included and they have not been constrained to monophyly, they have generally been depicted as paraphyletic with one or more heterosporous species placed as sister to the seed-plants (reviewed by Hilton and Bateman, 2006). The primary candidates are Archaeopteris halliana (Upper Devonian Phillips et al., 1972), Protopitys scotica (Mississippian Walton, 1957) and Cecropsis luculenta (Pennsylvanian Stubblefield and Rothwell, 1989). 

Fig. 2.1 Phylogenetic tree of the lamiids sensu Bremer et al. (2002) (syn. Euasterids I) established by cladistic analyses based on molecular data sets outgroup CampanuUds sensu Bremer et al. (2002) (syn. Euasterids II) for details and further references see text...

Fig. 2.3 Phylogenetic tree of the Convolvulaceae established by cladistic analyses based on molecular data sets (Stefanovic et al. 2003) outgroup Solanaceae for deteiils see text. Genera in bold indicate the significance for this book (presence of phytochemical data in the literature for this specific genus), in addition the genus Cressa ought to be printed in bold-face genera in standard type indicate that there are no data available...

De Luna, E., Buck, W. R., Akiyama, H., Arikawa, T., Tsubota, H., Gonzalez, D., Newton, A. E. and Shaw, A. J. (2000) Ordinal phylogeny within the hypnobryalean pleurocarpous mosses inferred from cladistic analyses of three chloroplast DNA sequence data sets trnL-F, rps4, and rbcL. Bryologist, 103 242-256. 

Morphologically some of these results make little sense, even if the support for some of the suggested relationships was moderately strong to strong. This example demonstrates that results from cladistic analyses of limited molecular datasets may not be more reliable than limited morphological and anatomical datasets, and that neither should be used uncritically for suggesting relationships among taxa. 

Nielsen, C., Scharff, N. and Eibye-Jacobsen, D. (1996) Cladistic analyses of the animal kingdom . Biological Journal of the Linnean Society, 57, 385-410. 

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