Aktipis, S. H., G. Giribet, D. R. Lindberg, and W. F. Ponder.  2008.  Gastropod Phylogeny:  an Overview and Analysis.  Pp. 199- 236 in Phylogeny and Evolution of the Mollusca.  (W. F. Ponder & D. R. Lindberg, eds.). University of California Press, Berkeley.



Abstract. This study is the first to use multiple molecular loci (ca. 3.2 Kb) and 166 morphological characters in a simultaneous analysis to provide one of the most comprehensive analyses of internal relationships among major gastropod clades. In this study, hypotheses of gastropod phylogeny based on the analysis of morphological or molecular data sets alone differed dramatically. Furthermore, results for individual molecular partitions were unstable because alignment parameters were varied, and only when the morphological data was included did the results become more stable. The monophyly of Gastropoda was not obtained under any molecular partitions, but after the inclusion of morphological characters a monophyletic Gastropoda was recovered.  Additionally, the jackknife support for most other clades increased in the combined analysis of all data; morphology provided additional support to the deepest nodes, while molecules in general added support to the shallower nodes of the tree. This result supports the arguments of proponents of the total-evidence approach; the most reliable evolutionary hypothesis for a particular group can be generated only by using all available data in the analysis.


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