[Publius]

However, the body lacks ambulocetus' legs. (Maybe they rotted away.) It looks like a descendant of ambulocetus that took a more streamlined shape, much like the earliest whales.

[Lady Jag]

I'd imagine the legs would have gone; there wasn't much to them.

Lack of Streamlining would be due to the skeletal collapse.

I'm trying to recall photos from long ago of a long dead sea creature that was pulled ashore by fishermen. One of the last reports of the hard to identify creature took into account post mortem occurrences.