That's fascinating! Do you know any references for that?
There was a short review in either Science or Nature at the time that the latest terrestrial whale discoveries were published, either 2001 or 2002. I'm actually working with that literature now, so I'll edit this post with a more specific reference when I get back from work.
--Axe
Edit: Here' s the ref for the journal:
Science vol. 293, 21 September 2001
The article I have at hand is by Gingerich et al. starting on p. 2239. There's another article describing a similar (but completely independent, believe it or not) discovery by Thewissen et al. in Nature. There's also a News and Views kind of review by someone (deMuizon?) near the front of the issue, but I can't remember if it's the Science or the Nature.
Here's the full ref for the Nature article:
Thewissen, J., E. Williams, L. Roe, and S. Hussain. (2001) Skeletons of terrestrial cetaceans and the relationship of whales to artiodactyls. Nature 413: 277-281.
EDITED AGAIN: In order to add the info for the Nature article.