Testing the Generality of Macroevolutionary Patterns with Bellerophont Molluscs

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The primary goal of this project is to test the idea that macroevolutionary parameters might be fairly general among larger groups. Bellerophontiform molluscs share numerous shell characters with contemporaneous gastropods even though bellerophonts are bilaterally symmetrical whereas early gastropods are asymmetrical. Workers consider many of these features to have similar biological implications for both bellerophonts and asymmetrical gastropods. If so, then PI expects to see similar rates of change in those characters as well as similar driven trends (i.e., biased productions of particular character states). He will evaluate alternative hypotheses using likelihood approaches designed by the author to simultaneously test phylogenetic and character evolution parameters. In doing so, tests will assess whether character parameters for bellerophonts are significantly different than for asymmetrical gastropods and, if so, in what ways. A secondary goal of the study is to test basic ideas about bellerophont relationships, such as whether they are monophyletic or polyphyletic, and ideas about how closely related bellerophonts are to asymmetrical snails.