text: what is the common name of "pseudoceros dimidiatos"? this is for a science project. there is a marine flatworm named pseudoceros dimidiatus, that lives in the seas around bali and indonesia.  i imagine that is the critter you are refering to.  it doesn't really have a common name though.  i guess the only ones who care about marine flatworms are people who use the scientific names.  it is a very attractive marine flatworm though, jet black with blazing yellow stripes.  very pretty.