The phylogenetic relationships of eight genera within the Calappidae H. Milne Edwards, 1837 (Crustacea: Brachyura) were examined based on a cladistic analysis of 55 adult morphological characters. A single tree was produced (CI=0.833, RCI=0.717). The data revealed two major lineages within the Calappidae: the ‘calappine’ clade, consisting of Calappa, Cryptosoma, Cycloes, Paracyclois and Cyclozodion, and the ‘mursiine’ clade, consisting of Acanthocarpus, Mursia and Platymera. Analyses of the fossil record and biogeographic patterns point to vicariance events associated with Gondwanan fragmentation. Optimization of depth distributions on the cladogram suggests that the family had a deep-water origin with only a single lineage moving into shallow waters.
