[AndrewC]

Is Pezosiren portelli a likely real ancestor of modern sirenians or are you frantically combing the literature to undermine yet another new piece of evidence for what you accepted long ago?

I choose to what I comment. But your link provides this

This reconstruction is a composite, including bones from several individuals. Most elements of the skeleton are represented by actual fossils, except for the following: jugal (= zygomatic), atlas, most of the caudal vertebrae, xiphisternum, fibulae, carpals, tarsals, most metapodials, and most phalanges. The bones painted a lighter color are restored based on their shape in related animals.

[VadeRetro]

This reconstruction is a composite, including bones from several individuals. Most elements of the skeleton are represented by actual fossils, except for the following: jugal (= zygomatic), atlas, most of the caudal vertebrae, xiphisternum, fibulae, carpals, tarsals, most metapodials, and most phalanges. The bones painted a lighter color are restored based on their shape in related animals.

As expected, a one-sided analysis, an attempt to undermine. You can get an idea of how much white there is from looking at the picture. So, is it a legged sirenian or not? There's no question it had legs. If it's a sirenian, you can add another vertebrate transitional to Kathleen Hunt's list.

So what do you believe accounts for the diversity of life on Earth? Would this something have produced the fossil record we have so far?

What is the frantic haste to discredit the evidence for what you believe? Do you really accept what you "believe?" Clarify, please!