Whale Evolution

Last night on All Things Considered, they had a story about fossil whale ancestors:

They say that they are related to “even toed ungulates” like dear and hippos.

I thought that the thinking was that the whales came from the meonyschids (sp), a line that had died out – except for whales and pinnipeds.

Is this a change in thinking? Or, are they now saying that the meonyschids (sp) were even toed ungulates?

oops, that “dear” should be “deer”. I am in no way implying that my wife is an even toed ungulate.

The BBC has a nice diagram that may help. (or maybe it won’t)

So does the University of Arizona.

Darn. I should have remembered to mention that being related to a group or taxon is very different from being descended from a group or taxon. (And an extant species cannot be descended from a monophyletic taxon, it can only be a member of that taxon… cladistically speaking).

Are Meonyschids now considered related to the even toed ungulates? If not, how is this new? Is the ankle the “smoking gun” people knew would be there?

From what I’ve gathered without going through too many sources:

This isn’t particularly new since molecular phylogenies have placed the Cetaceans with the even-toed ungulates (Artiodactyla) previously (case in point: Buntjer, J. B., I. A. Hoff, and J. A. Lenstra. 1997. Artiodactyl interspersed DNA repeats in cetacean genomes. Journal of Molecular Evolution 45:66-69.), but this may either be the first morphological corroboration of the molecular evidence or the press picking up on things a few years after they happen (not too unusual in science reporting). My guess is that your comment about the “smoking gun” is correct.

The Mesonychia are thought to have diverged from the even-toed ungulate lineage at about the time of the “late Cretaceous or the early Paleocene,” according to Gingerich and Uhen, at least.