Dorsal Fins

[zopteryx]

We know most (if not all) ichthyosaurs had them, but what about mosasaurs? And ancient whales like Basilosaurus, would they have had a dorsal fin like they are usually depicted, or more of a Gray/Humpback Whale type ridge?

Thanks for the help!

[Griffin]

I'm pretty sure mosasaurs wouldn't have had a dorsal fin on the back. There has been a specimen found that is very nicely preserved and there is no evidence of such a thing. They did have a tail fluke like a shark though.

I have no clue about whales.