Ska is roughly a mixture of calypso and jazz. It is more percussive than melodic and very upbeat.
Raggamuffin is a sub-style of dancehall (more electronic), reggaeton is an urban mix of reggae (Sean Paul, Daddy Yankee. Reggaeton can also be a part of Latino music) and reggae-fusion is a mix of reggae and the genres popular in America, like R&B, jazz and hip hop.
Read more at Buzzle: http://www.buzzle.com/articles/different-types-of-music.html