No abstract

The introduced Asian parasitic bopyrid isopod, Orthione griffenis, was first discovered on the Pacific coast of North America in Washington in 1988 and next in California in 1992. The range of Orthione presently extends from British Columbia to Baja California, where it infests at least two species of the native estuary mud shrimp, Upogebia. Intense Orthione infestations are associated with the apparent demise of many local populations of Upogebia pugettensis yet nonindigenous origins of Orthione in North America and thus the ecological significance of its impacts have remained in doubt. Six criteria reveal that Orthione is introduced to North America: its conspecificity with disjunct Asian populations, its earliest (1950s) collections in Asia, its late discovery among symbiotic species associated with Upogebia, its historical absence, and its appearance in North America coincident with extensive new ballast water traffic from Asia. Orthione is the first recognized bopyrid isopod invasion globally. Coexistence of U. pugettensis, which are ecosystem engineers, with its newly acquired parasite cannot be assumed. Orthione threatens eastern Pacific estuary ecosystems where Upogebia were previously abundant.

No abstract

Aporobopyrus bourdonis, new species, earlier reported from the Pacific coast of Mexico but never described, infests Petrolisthes edwardsii (de Saussure), the same host species as before, in Costa Rica. Aporobopyrus muguensis Shiino, 1964, previously reported several times along the coast of California infesting Pachycheles rudis Stimpson and P. pubescens Holmes, is redescribed on the basis of material from Monterey, California, infesting P. pubescens. Aporobopyrus trilobatus (Nierstrasz and Brender a Brandis, 1925), previously known from the Caribbean Sea and the Pacific coast of Mexico, infests Petrolisthes ortmanni Nobili, a new host record, in Costa Rica. Discomorphus magnifoliatus, new genus, new species, infests Petrolisthes cinctipes (Randall) in central California. Synonymies are given for all species. BOPYRID ISOPODS OF PACIFIC AMERICAN COAST 147

No abstract