ABSTRACT
Although the crab superfamily Majoidea is well recognized as a distinct grouping within the Brachyura, resolving the classification of and relationships between different majoid families has been more difficult. In this study, we combine molecular and larval morphology data in a total evidence approach to the phylogeny of the Majoidea, using sequence data from three different loci and 53 larval morphology characters from 14 genera representing 7 majoid families. We examine the relative contribution of morphological and molecular characters in resolving relationships within the superfamily Majoidea and how different alignment and tree construction methods affect tree topology. Using maximum parsimony analyses and partitioned Bremer support, we show that molecular and larval morphology partitions are congruent in combined analyses and that both types of characters contribute positively to resolution of the tree and support for major nodes. Both Bayesian analysis and direct optimization of nucleotide sequences under parsimony supported some similar relationships, including a monophyletic Oregoniidae branching at the base of the majoid tree. However, Bayesian and direct optimization trees differed in their resolution of some relationships, namely in placement of inachid and tychid species relative to the remaining majoids. Neither Bayesian nor direct optimization trees of the combined dataset supported monophyly of the majority of majoid families proposed in recent taxonomic revisions of the group, suggesting the adult morphological characters used to classify majoids into families may be incongruent with larval characters and molecular data used in this study.
