Meeting Abstract

S8-2.4  Saturday, Jan. 5  Parasites as Phylogenetic Indicators in Decapod Evolution BOYKO, C.B.*; WILLIAMS, J.D.; Molloy College; Hofstra University cboyko@molloy.edu

The phylogenies of parasitic organisms and their hosts exhibit varying degrees of congruence based on the events their historical association (e.g., cospeciation, host switching). Comparison of two major groups of decapod parasites, the Bopyridae and Rhizocephala, shows two very different patterns of speciation. In the Bopyridae, only approximately 15% of described species occur on Brachyuran hosts, while in the Rhizocephala the majority of described species are in the Sacculinidae and are almost all on brachyurans. Although brachyurans are putatively the most recently evolved decapods, and the most rapid in terms of speciation rates, they are apparently not equally attractive hosts for all parasites. The rhizocephalans appear to have matched the rapid speciation rates of the brachyurans, while the bopyrids have not. The relatively low number of bopyrids in brachyurans does not appear to be due to increased carcinization as a barrier, since bopyrids have been evolutionarily successful in anomurans groups such as galatheids and porcellanids, which are �crab-like� in their overall morphology. Data is presented on the differing patterns of host specificity within both groups of parasites, with special emphasis on groups of parasites that show cospeciation with their decapod hosts as well as those which appear to show patterns incongruent with decapod evolution as currently understood.