CHANGES IN MORPHOLOGY, DIVERSITY, AND ENVIRONMENT IN THE SPONGE CRABS (DECAPODA, BRACHYURA, DROMIOIDEA) FROM THE CRETACEOUS TO HOLOCENE

The Superfamily Dromioidea is one of the earliest groups of extant crabs to appear in the fossil record. Though the superfamily has been recognized since the 1800s, a comprehensive study of the evolution, paleoecology, and biogeography of fossil extant members has yet to be conducted. Dromioidea first appeared in the fossil record in the Cretaceous, and members of three of the included families still exist today. Dromioidea are typically considered as coral associated crabs. By investigating the changes through time that Dromioidea have experienced, trends in change in locations inhabited and body size can be correlated with climate change through time. Faunal turnover has been previously established (Schweitzer and Feldmann, 2015) as an important trend in brachyurans and their role in the ecosystem. Preliminary analysis suggests that since the Cretaceous, members of the superfamily have changed environmental preferences in terms of depth and latitude, moving deeper and toward the tropics. Initial studies also indicate that overall carapace size has increased through time. With the current threats to corals due to climate change and other environmental stressors, this study is intended to offer insight into environmental changes that were factors in the extinction of members of Dromioidea.