GARB, J.E.*; GILLESPIE, R.G.: Parallel patterns in the Pacific? A comparison of phylogenetic diversification in crab spiders (Araneae: Thomisidae) across three Polynesian archipelagos.
Crab spiders of the genus Misumenops(Araneae: Thomisidae) have repeatedly colonized and diversified on a number of Pacific island archipelagos. Depsite the similarity in the geologic formation of the Hawaiian, Society and Marquesan archipelagos, their endemic crab spider faunas possess remarkably different levels of diversity. Twenty-one crab spider species have been described from the Hawaiian Islands. These species are exceptionally diverse in coloration, reflecting their specialization of mimicry onto several different microhabitat types. In contrast, only one species is known from both the Marquesan and Society Islands. In an effort to understand if the different patterns exhibited in these three archipelagos is a result of different levels of colonizations and/or in situradiation, we conducted a phylogenetic investigation of Polynesian crab spiders using both molecular and morphological characters. The results of a combined analysis of morphological and mitochondrial DNA sequence data indicate that although a greater number of colonization to the Hawaiian archipelago may partially account for its species richness, the greater levels of morphological diversity exhitibed by the Hawaiian crab spiders are likely to have resulted from rapid in situdiversification.