Maristentor dinoferus was described in 2002, after it was first discovered on the coral reefs on Guam in 1996. However, until now its phylogenetic position has been puzzling. The 18S-ITS1-5.8S rDNA sequence of M. dinoferus is 320 bp including 222 bp from 18S rRNA gene, 77 bp from ITS1 region and 22 bp from 5.8S rRNA gene. Comparison of lengths of the ITS1 domain from the main ciliate groups(classes)was done, and it shows that short ITS1 may be the characteristics of heterotrichs. 18S rDNA sequence of M. din...