Pseudoklossia haliotis sp. n. (Apicomplexa) from the kidney of California abalone, Haliotis spp. (Mollusca)

A coccidian of the genus Pseudoklossia Leger and Duboscq, 1915 (Apicomplexa) occurs in the kidneys of abalone, Haliotis spp. (Mollusca), throughout waters off California. Parasites are often numerous in renal tissues, and developmental stages include oocysts, macrogametes, microgametocytes, and meronts. Renal coccidian infections occur in uninfected abalone after exposure to water occupied previously by infected animals. The life cycle of this parasite appears to be monoxenous and the coccidian evokes no host inflammatory response. We term this coccidian Pseudoklossia haliotis sp. n. and describe the morphologic characteristics of the endogenous stages and oocysts. This represents only the seventh named species described from the genus.