Mesanophrys chesapeakensis n. sp., a Histophagous Ciliate in the Blue Crab, Callinectes sapidus, and Associated Histopathology

Abstract

Histophagous ciliate infections were infrequently detected in blue crabs, Callinectes sapidus, from Chesapeake Bay, Delaware Bay, and a coastal bay of Maryland. Associated pathology included hemocyte aggregations in various tissues and nodule formation. Protargol silver staining of cultured ciliates revealed an oral apparatus morphologically similar to that of other hemolymph-infecting ciliates of the genus Mesanophrys. The oral apparatus included three distinct oral polykinetids and an oral dikinetid consisting predominantly of a b segment and a smaller c segment. Morphologic comparison to other histophagous ciliates infecting crustaceans showed that the ciliate in blue crabs is a distinct species, Mesanophrys chesapeakensis n. sp., family Orchitophryidae. Additional key words: protargol, Orchitophryidae Histophagous ciliates from wild and captive crustaceans have been reported sporadically from various locations since 1888. The ciliate Mesanophrys (Anophrys COHN 1866) maggii CATTANEO 1888 was first reported parasitizing the hemolymph of a European shore crab, Carcinus maenus LINNAEUS 1758, from Italy. Incomplete or poor morphological descriptions of several crustacean-infecting ciliates have caused considerable confusion and elicited much discussion on systematics (Armstrong et al. 1981). Based on the morphology of oral structures of protargol-stained specimens, a new genus, Mesanophrys, was erected by Small & Lynn (1985) to include ciliates with only a short oral dikinetid and other features now found in the genera of the family Orchitophryidae. Two species, Mesanophrys (Paranophrys) maggii CATTANEO 1888, and Mesanophrys (Anophrys) carcini GROLIERE & LEGLISE 1977 (Small & Lynn 1985), were transferred into this newly erected genus; a third species, Mesanophrys pugettensis MORADO & SMALL 1994, was recently reported. However, incorrect generic placements of histophagous ciliates from crustaceans have continued, as discussed by Morado & Small (1994). Recently, the family Paranophryidae (JANOWSKI, in Small & Lynn 1985) was determined to be a junior synonym a To whom correspondence should be addressed: Gretchen Messick 410-226-5193 FAX: 410-226-5925 e-mail gmessick @ hatteras.bea.nmfs.gov. of Orchitophryidae CEPEDE 1907, due to rule of priority (Morado & Small 1994). Orchitophrya stellarum CEPEDE 1907 was recently reinvestigated using protargol staining and was determined to be a scuticociliate rather than an astome (Bouland et al. 1986). Thus, Paranophryidae falls as a junior synonym to Orchitophryidae (Morado & Small 1994). Most reports of ciliates in crustacean hemolymph involve captive hosts (Cattaneo 1888; Bang et al. 1972; Aiken et al. 1973; Groliere & Leglise 1977; Armstrong et al. 1981; Sparks et al. 1982). Reports of histophagous ciliates in wild crustacean populations are rare, and infection prevalence has typically been low. Poisson (1930) found only 0.2% (7 of 3000) shore crabs, C. maenus, infected with histophagous ciliates. Infections in wild stocks of the American lobster, Homarus americanus H. MILNE EDWARDS 1837, were found only three times in 14 years (Aiken & Waddy 1986). In contrast to these reported low prevalence levels in hemolymph of wild lobsters, a ciliate was present in smears of hepatopancreas tissue of all freshly caught Maine lobsters, H. americanus (n=89), although the ciliate was often undetected in hemolymph preparations (Sherburne & Bean 1991). Mesanophrys pugettensis was found in fewer than 0.4% (n=1916) of wild and captive Dungeness crabs, Cancer magister DANA 1852, although it was reported in 3% (n=87) of wild rock crabs, C. productus RANDALL 1839, and 29% (n 7) of wild kelp crabs, Pugettia producta RANDALL This content downloaded from 157.55.39.153 on Mon, 19 Sep 2016 04:45:06 UTC All use subject to http://about.jstor.org/terms