NEW RECORDS OF ELLOBIOPSIDAE (PROTISTA 



(INCERTAE SEDIS)) FROM THE NORTH PACIFIC WITH 



A DESCRIPTION OF THALASSOMYCES ALBATROSSI N.SP., 



A PARASITE OF THE MYSID STILOMYSIS MAJOR 



Bruce L. Wing^ 



ABSTRACT 



Ten species of ellobiopsids are currently known to occur in the North Pacific Ocean — three on 

 mysids and seven on other crustaceans. Thalassomyces boschmai parasitizes mysids of genera 

 Acanthomysis, Neomysis, and Meterythrops from the coastal waters of Alaska, British Columbia, 

 and Washington. Thalassomyces albatrossi n.sp. is described as a parasite of Stilomysis major 

 from Korea. Thalassomyces fasciatus parasitizes the pelagic mysids Gnathophausia ingens and 

 G. gracilis from Baja California and southern California. Thalassomyces marsupii parasitizes the 

 hyperiid amphipods Parathemisto pacifica and P. libellula and the lysianassid amphipod Cypho- 

 caris challengeri in the northeastern Pacific. Thalassomyces fagei parasitizes euphausiids of 

 the genera Euphausia and Thysanoessa in the northeastern Pacific from the southern Chukchi 

 Sea to southern California, and occurs off the coast of Japan in the western Pacific. Thalassomyces 

 capillosus parasitizes the decapod shrimp Pasiphaea pacifica in the northeastern Pacific from 

 Alaska to Oregon, while Thalassomyces californiensis parasitizes Pasiphaea emarginata from 

 central California. An eighth species of Thalassomyces parasitizing pasiphaeid shrimp from Baja 

 California remains undescribed. Ellobiopsis chattoni parasitizes the calanoid copepods Metridia 

 longa and Pseudocalanus minutus in the coastal waters of southeastern Alaska. Ellobiocystis 

 caridarum is found frequently on the mouth parts oi Pasiphaea pacifica from southeastern Alaska. 

 An epibiont closely resembling Ellobiocystis caridarum has been found on the benthic gammarid 

 amphipod Rhachotropis helleri from Auke Bay, Alaska. Where sufficient data are available, notes 

 on variability, seasonal occurrence, and effects on the hosts are presented for each species of 

 ellobiopsid. 



The family Ellobiopsidae (Protista {incertae 

 sedis)) is a heterogeneous group of parasites and 

 epibionts found on various crustaceans (mostly 

 planktonic) and on the benthic polychaete worm 

 Nephthys ciliata Miiller. The Ellobiopsidae have 

 been classified at various times as protistans, 

 colorless algae, fungi, or protozoans. The recent 

 work of Gait and Whisler (1970) suggests includ- 

 ing the parasitic ellobiopsids among the dino- 

 flagellates. 



The parasitic ellobiopsids are multinucleate 

 protistans with reproductive structures out- 

 side the host and absorptive portions inside. 

 The reproductive structures often resemble a 

 large mold; consequently, much of the descrip- 

 tive terminology of ellobiopsids is mycological. 

 The reproductive parts of an ellobiopsid (Figure 

 1) consist of a short primary stalk passing from 



'Northwest Fisheries Center Auke Bay Laboratory, National 

 Marine Fisheries Service, NOAA, P.O. Box 155, Auke Bay, 

 AK 99821. 



SIEVE PLj^TE — ^ 

 ABSORPTIVE FILAMENTS 



-D 



ORGAN OF FIXATION 



Manuscript accepted April 1974. 



FISHERY BULLETIN: VOL. 73. NO. 1, 1975. 



Figure 1. — Schematic of an ellobiopsid (Thalassomyces sp.) 



the organ of fixation through the cuticle of the 

 host and one or more trophomeres which branch 

 from the primary stalk. The trophomeres in turn 

 bear one or more gonomeres at their distal end. 



169 



