Summary[edit] Description: the castrating parasitic barnacle Loxothylacus panopaei, infecting Eurypanopeus depressus. Little Annemessex River, Somerset County, MD - 06/21/13. Photo by Robert Aguilar, Smithsonian Environmental Research Center. Date: 13 September 2006, 04:11. Source: Loxothylacus_panopaei_(I0266). Author: Smithsonian Environmental Research Center.