I forgot her name, but the former no.31 (or 30? Tabatha I think) was observing Riful as their eye. Like you said, her proficiency doesnt match up anywhere close to Galatea's, but they're the same type of skill. Back during the first arc with Miria, she said that her sensing range could cover the mountain area which they were in, so I assume that this other girl's range is greater (or greatest in the group) if Miria asks her to scout.

Actually I'm a bit interested in seeing what will become of Cynthia. Other than being the next-highest ranked to not be targeted by the Lion (heh... too lazy to search the archives for another name ><) we don't really know anything about her except that she was a defensive type.