The parasitic dinoflagellates of marine crustaceans

Abstract

Abstract. Parasitic dinoflagellates have recently emerged as significant disease agents of commercially important crustaceans. For example, epizootics of Hematodinium have seriously affected certain crab and lobster fisheries. The parasitic dinoflagellates of crustaceans are, however, relatively unknown. Marine crustaceans are parasitized by two orders of dinoflagellates: the Blastodinida and the Syndinida. Crustaceans are also parasitized by the Paradinida and the Ellobiopsidae, taxa that have close historical ties and possible taxonomic affinities with the dinoflagellates. The taxonomy and life history patterns of the different parasitic species are largely dictated by their host-parasite relationships. For example, sporulation in the blastodinids occurs internally but is completed externally with the expulsion of spores via the anus of the host. The egg-parasitic chytriodinids sporulate externally after destroying their host egg. The tissue-dwelling syndinids have plasmodia that sporulate internally and generally kill their hosts upon the expulsion of the dinospores. Unfortunately, complete life cycles have not been elucidated for any of the parasitic forms, hence characteristics of the life cycles must be applied cautiously to the systematics of the taxa. For example, gamogony and the presence of resting cysts are only known from a few species; they probably occur in most species. Further work on the life cycles of the parasitic dinoflagellates of crustaceans should concentrate on establishing the life cycles of representative species from each order or family. Parasitic dinoflagellates infect copepods, amphipods, mysids, euphausiids, and decapods. Their pathogenicity varies with their invasiveness in the host. The gut-dwelling blastodinids are relatively benign, while the chytriodinids kill their host egg. Members of the pervasive Syndinida and Paradinida are overtly pathogenic and insidiously ramify throughout the hemal sinuses and organs of their hosts. Members of the Ellobiopsidae vary from the commensal Ellobiocystis to the overtly parasitic Thulassomyces. Host castration and feminization are common pathologic results of infection by these parasites. The severity of the castration is dependent upon the invasiveness of the parasitic species and the duration of the infection, while the degree of feminization is related to the stage at which the host acquires the infection. Most of the parasitic dinoflagellates occur in epizootics in their host populations. Recent epizootics of Hematodinium spp. have had severe effects on crustacean fisheries in Alaska, Virginia, and Scotland, and may potentially result in changes to the benthic communities of the hosts. The epizootics are often associated with host-parasite systems that occur in regions with unique hydrological features, such as fjords or poorly draining estuaries with shallow sills. These regions are ideal for the application of a "landscape" ecology approach that could lead to a better understanding of the epizootiology of parasitic dinoflagellates and ...

Blastodinium galatheanumsp. nov. (Dinophyceae) a parasite of the planktonic copepodAcartia negligens(Crustacea, Calanoida) in the central Atlantic Ocean

“…GenBank accession numbers are given in Figure 28. been found in several host species, but never in Acartia (Shields, 1994). Another slender species with some resemblance to B. galatheanum is B. elongatum, which can reach up to 600 mm  80 mm (Chatton, 1912).…”

“…Table 2 summarizes the species within the genus; a more extensive list of Blastodinium hosts was given by Shields (1994). It appears that Blastodinium is particularly common in warm temperate and tropical waters (Chatton, 1920;Skovgaard & Saiz, 2005) and that the genus is rarer in cold temperate waters (Appstein, 1911;Jepps, 1937).…”

“…These species nourish themselves as functional parasites of an array of aquatic protists and metazoans (Drebes, 1984). Several parasitic dinoflagellate species cause diseases in aquatic organisms (Shields, 1994;Coats, 1999), and some are threats to populations of fish and crustaceans of commercial interest (Brown & Hovasse, 1946;Stentiford & Shields, 2005). Parasitic dinoflagellates have generally received less scientific attention than their free-living relatives.…”

Nucleotide sequence determination of the partial SSU rDNA gene and ITS1 region of Hematodinium cf. perezi and Hematodinium-like dinoflagellates

“…Marine crustaceans are parasitized by 2 orders of dinoflagellates: the Blastodiales and the Syndiniales (Shields 1994). In the Syndiniales, the type species, Hematodinium perezi Chatton & Poisson, 1931, was described from the portunid crabs Carcinus maenus and Portunus depurator; the second species, H. australis Hudson & Shields, 1994, was described from another portunid, Portunuspelagicus.…”

First Observations of Tumor-Like Anomalies in Planktonic Copepods in the Crimean Coastal Waters

“…Ellobiopsidae часто отмечаются как парази-ты веслоногих ракообразных (Théodoridès, 1989;Shields, 1994;Bridgeman et al, 2000;Albaina, Irigoien, 2006;Konovalova, 2008). Это семейство представляет собой небольшую гетерогенную группу паразитических про-тистов, имеющую несомненное родство с динофлагеллятами, однако четко системати-ческое положение эллобиопсид не определе-но (Bridgeman et al, 2000;Konovalova, 2008).…”