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

Partial sequences of the small subunit (SSU) rDNA g e n e of the parasitic dinoflagellates Hematodinium cf.perezi from the blue crab Callinectes sapidus and 3 Hematodjnium-like organisms from other decapods, Nephrops non~egicus, Chionoecetes bairdi and C. opilio, were compared.The V9 variable domain of this gene showed no nucleotide differences between the 4 parasitic dinoflagellates.Comparison of this region with other protozoans suggested that the 3 Hematodiniun~-like organisms should be considered to be within the genus Hematodinium Differences in nucleotide sequence in the partial ITSl regions from these 4 parasitic dinoflagellates suggest that there are 2 new species.The Hematodinium organism ex N. norvegicus warrants the creation of a new species.The Hematod~nium organisms ex C. bairdi and C, opilio are probably the same species and also warrant the creation of another new species, while H. cf.perezi remains distinct from the other isolates.