Yes it’s time for some more “stinkin’ mammals”, though in my defence I generally keep the place pretty synapsid-free. Anyway, one of the truly great transitional series in palaeontology is the origin of whales. It’s not a surprise really, they are relatively big and recent animals that hung around in water, all things that help fossilisation. Combined with their nicely diagnostic anatomy and the public’s general affection for cetaceans, this makes them a superb example of a major transition (here from land to water, obviously) as well as making the origin and radiation of an important clade. I’ve used it in my lectures and it seems to be a particularly popular subject with the students.
Among other things, the aquatic section of the ‘history of life’ room in Toyko houses a magnificent collection of casts of various stem whales. From Ambulocetus, Pakicetus and Basilosaurus (and indeed others) there is a lovely and clear pattern of the shape of the skull and teeth changing and the back elongates, and the hindlimbs atrophy. Put together, it’s a great series and I spent some time photographing as much of it as possible for my lecture notes. I’ll be able to make better use of this in the future thanks to such a great set-up.
Kutchicetus
Kutchicetus skull
Ambulocetus
Ambulocetus skull
Pakicetus
Pakicetus skull
Durodon
Durodon skull
Durodon hindlimbs
Basilosaurus
Basilosaurus skull
Dave Hone's Archosaur Musings 
I saw a similar series sans Basilosaurus in a temporary exhibit in the Naturalis museum, Leiden, NL back in June. It really is striking to see. Thanks for the photographs.
No worries. I’d like to flesh it out if anyone had Indohyus or Maiacetus or something similar.
That stinkin’ synapsid on the top should be Kutchicetus from the western Indian region of Kutch. It forms a clade of basal whales with Remingtonocetus. They appear to have been a group of small longirostral whales that retain both the ancestral mammalian land hearing type ear and also an incipient water hearing ear.
Ah yes, sorry my bad typing again, I’ll fix it.
It’s also Dorudon, not Durodon. Awesome shots.
Now that one is not a typo, that’s me having the name wrong in my head. Though I should have realised as the teeth really don;t look like durophage and that had been bugging me!
Those Remingtonocetids look like someone’s taken a giant otter and tried to turn it into a gharial. I wonder what its bite strength would have been like- that’s a whopper of a saggital crest its got there.
More American museums need exhibits like this. There’s a lot of emphasis on what lived where and when, how they interacted, and eferences to major events, but when it comes to evolution, there tends to be the occasional statement and not much else. Small wonder that creationism is so popular over here, with people denying the existence of transitional forms. Displaying a series of transitional fossils like this would get the point across so much better than any labels could.