One way to think of potato, a type of articulation, is as a slightly sustained, or lengthened staccato. In fact, portato is sometimes called mezzo-staccato, and may be indicated with slurs over staccato marks. However, slurs over staccatos don't always imply portato articulation: sometimes a slur mark is not an articulation mark at all, but simply a structural indication of note groupings which might effect dynamic shaping and rubato instead of articulation.