Bebej: A Maiacetus Fossil

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Responding to @John_Harshman now:

How weird is it that Thewissen and Gingerich published the first whale astragali nearly simultaneously? And both soon after the first SINE data were published?

I’m not going to divulge anything specific here because it’s not really my place to share secondhand accounts in a forum like this, but the timing of those two papers was not really all that coincidental. If you want to get in the weeds on this, just look at the submission/acceptance/publication dates of the papers, along with the acknowledgments for who provided feedback on the manuscripts…

Do you have any opinion on the phylogenetic position of mesonychids? Of Andrewsarchus ?

I haven’t kept up much on where exactly folks place mesonychids relative to all other ungulates, but I do consider them outside of Cetartiodactyla and not closely related to Cetacea.

Do you think the evolutionary story of whales would convince a creationist? Have you ever discussed that with a creationist?

I guess it depends on how open-minded the creationist was. I’ve certainly had many conversations with creationists over the years, but I tend not to participate in debates. I almost always talk about my work and why I find the evidence for whale evolution to be so compelling, but I recognize the variety of reasons why some well-meaning Christians can have trouble with that. My goal is generally to try and have thoughtful and respectful conversations with people, trying to help them to see that even folks with an evolutionary perspective on the world can still be brothers and sisters in Christ.

What do you think of Kurt Wise’s notion that artiodactyls might be a “kind” and that whales evolved over a hundred years or so after 2000 BC?

This is crazy to me. In supporting a position like this, they’re suggesting that evolution can render profound changes far more quickly than even the most ardent evolutionary biologists would imagine. Joel Duff has written about the evolution of this hyper-speciation model in YEC circles at his blog, and it is absolutely fascinating. I also know that they have a Pakicetus on the Ark Encounter, but I don’t know whether they’re suggesting that it was a now extinct creature unrelated to any modern forms, or if it was the ancestor of all modern cetaceans, which have evolved since the flood.

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Replying to @evograd and @swamidass re: pregnant specimens:

As for Maiacetus, there are two known specimens. While many species are known by many partial specimens, there are also many species that are just known from a few – or even one!

I would say that pregnant specimens are rare – usually so exceptional that they warrant a detailed description, even if the species is already well known to paleontologists. For instance, this stunning specimen of a well-known fossil horse species made headlines a few years ago. But we do see these published frequently enough that they are on our radar when interpreting new fossil assemblages.

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@T.j_Runyon: I’d love to hear more about your work on basilosaurids! My work has mostly focused a bit earlier in cetacean history (pakicetids, ambulocetids, remingtonocetids, and protocetids).

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That is about what I expected. So 50% of the Maiacetus of which we know are pregnant, against a background population of, say, 1%. Of course, this is a low sample size, but the chances of this are 1 out of 50. Fairly low. It seems that this was a very fortunate situation.

Nonetheless, the reasoning on this is really helpful. I’m glad I am not the only one who was skeptical. In the end, with such sparse evidence, it makes sense that there are a lot of open questions.