Sequence of the small subunit ribosomal RNA gene of Perkinsus atlanticus-like isolated from carpet shell clam in Galicia, Spain

Parasites identified as Perkinsus atlanticus have been reported infecting c arpet shell clams in Galicia (northwest Spain). We have sequenced the 18S r ibosomal RNA gene of in vitro cultured Perkinsus atlanticus-like or hypnosp ores from diseased clams, and compared it with the same genomic region from P. marinus and Perkinsus sp. We have also compared the sequence of interna l transcribed spacer (ITS) 1, ITS 2, and 5.8S rRNA from our isolate with th e P, atlanticus GenBank sequence. The phylogenetic analysis of our cultured parasite based on the 18S gene led us to conclude that this isolate is not related to the genus Perkinsus but to the protists Anurofeca, Ichthyophonu s, and Psorospermium, located near the animal-fungal divergence. These last two genera have been included, together with Dermocystidium, in the newly described DRIPs (Dermocystidium, rossete agent, Ichthyophonus and Psorosper mium) clade, recently named Mesomycetozoa.