NatGeo YouTube video on Basilosaurus: a little out of date

My comments follow:
Stories of these desert whale skeleton bone beds became the source for the legends of long, sinuous Chinese dragons ‘king lizards’ with similar morphologies. So, that means someone (and his crew) back then dusted off at least one of these skeletons to see the whole thing some 2000 years ago – but did not take it with him. Apparentley too big and too many parts.

Most mammals can be distinguished by the cusps on their teeth. Fun fact: dolphins and sperm whales have no cusps on their teeth (see @36:38 in the video) so those teeth demonstrate a reversal to more simple teeth that goes back to pelycosaurs and the earliest therapsids also without cusps on their teeth. Basilosaurus (see @37:26 in the video) represents a transitional taxon in that reversal, with transitional teeth similar to those of pre-mammal cynodonts.

Another fun fact: since mysticetes evolved from hippos and desmostylians and Miocaperea (see Triple Origin of whales at ResearchGate) at the same time that odontocetes evolved from tenrecs, Leptictidium, Indohyus, pakicetids and basilosaurids there is no longer any such thing as a ‘whale’ and the former clade ‘Cetacea’ should no longer be used in the literature because it does not represent a monophyletic clade.

Why did Basilosaurus have vestigial legs? Because legs don’t disappear overnight or in one generation. Takes awhile. Don’t make it a bigger deal than it really is.

Why did odontocetes enter the water? That happened when Pakistan (and Pakicetus) split from Madagascar (and Tenrec) during the Late Cretaceous. That leaves lots of shallows and ocean and the tiny Seychelles islands between them. Note: Pakicetus and Phiomicetus are giant tenrecs.

@27:13 Dr Brusatte reports, ‘hippos are the closest living relatives of the whale.’ But broad-snouted hippos don’t look like pointy-snouted, sharp-toothed Pakicetus. That’s because Pakicetus gives us toothed whales. Hippos give us baleen whales. BTW, tenrecs use echo-location. Hippos and mysticetes don’t use sonar, but they both sing.

@27:50 Dr Brusatte attempts to compare Pakicetus to Hippopotamus. It can’t be done because they are not related to one another. “Kinda like” is not good enough in paleontology. Phylogenetic analysis is needed. See ‘the large reptile tree’ online for that wide gamut analysis.

@37:26 that mandible is disarticulated from the skull. Small point, but that’s why the upper and lower teeth do not line up.

@39:52 Moertherium is not an elephant relative but transitional from Castoroides (a giant seagrass-eating beaver) to sirenians, including the seagrass-eating manatee with the round beaver-like flukes. See ‘the large reptile tree’ online for the cladogram.

@42:17 the narrator reports, “Basilosaurus couldn’t echolocate.” This is wrong according to phylogenetic bracketing. We’ve known for a few decades that Tenrec can echolocate and has the same sort of asymmetrical skull mentioned @42:28.