Here is a nice addition to our discussion of Dawkin's whale fossil presentation, discovering origins and relationships from an earlier time:- http://www.sciencedaily.com/releases/2009/09/090924185533.htm-I have also mentioned bilaterians as a group immediately preceding the Cambrian Explosion. An article concerning them:-http://www.sciencedaily.com/releases/2009/09/090923112543.htm