I remember speaking some time back-about 1yr ago to a friend and he mentionned a NZ species of shrimp that is a hermaphrodite. This shrimp starts out as juvie males and as it matures becomes a fully functional female. It is a member of the Atyidae group and is named Paratya curvirostris. More info can be found here http://www.nzfreshwater.org/crustacea.html
If anyone has contacts I'd like to acquire some of these or the little crab found further down the page.