Ambulocetus Has No Pelvis
and is Largely Incomplete?

Jonathan Sarfati of Answers in Genesis in a rebuttal to the second episode of the PBS series Evolution wrote:

Ambulocetus

This was mentioned fairly briefly in this episode, but it features prominently in the anti-creationist book Finding Darwin’s God, by Kenneth Miller who starred in Episode 1 (see rebuttal). On p. 265, Miller claimed, ‘the animal could move easily both on land and in water’, and contained a drawing of a complete skeleton and a reconstructed animal. But this is misleading, bordering on deceitful and indicative of Miller's unreliability, because there was no indication of the fact that far fewer bones were actually found than appear in his diagram. Crucially, the all-important pelvic girdle was not found (see diagram…). Without this, it’s presumptuous for Miller to make that proclamation. His fellow evolutionist Annalisa Berta pointed out:

‘ … since the pelvic girdle is not preserved, there is no direct evidence in Ambulocetus for a connection between the hind limbs and the axial skeleton. This hinders interpretations of locomotion in this animal, since many of the muscles that support and move the hindlimb originate on the pelvis.’ ¹

See also A Whale of a Tale?

…

1. Berta, A., What is a Whale? Science 263(5144):180–181, 1994; perspective on Thewissen, J.G.M., Hussain, S.T. and Arif, M., Fossil evidence for the origin of aquatic locomotion in Archeocete whales, same issue, pp. 210—212.

[All of Sarfati’s links are included, but the links to Miller and his book are mine.]

The same story is told in AiG’s August 17, 2001 Answers With Ken Ham radio segment with the hysterical title “Evolutionists - after our children!” Since this essay was first put online, AiG put up another article with this story by Ken Ham and Carl Wieland called “A Whale of a Tale.” (AiG has two articles by that name.)

The first thing I will do is to include a bit more context for the Berta quote:

…Thewissen et al. [i.e. the paper announcing Amulocetus; see AiG’s reference above] provide some solid comparative data to support their conclusions regarding the evolution of locomotion in whales; however, a well-corroborated phylogenetic context with which to interpret these character transformations would greatly enhance its utility. For example, since the pelvic girdle is not preserved, there is no direct evidence in Ambulocetus for a connection between the hind limbs and the axial skeleton. This hinders interpretations of locomotion in this animal, since many of the muscles that support and move the hindlimb originate on the pelvis.

Sarfati provided the following image:

Image is from “AiG’s response to PBS-TV series Evolution Episode 2.”
A better image of the middle and bottom can be found here.

The top figure is a skeleton reconstruction of Ambulocetus. The second is an artist concept of the fossil. Sarfati’s description of the bottom is “Actual bones found (Yellow). Note missing pelvic girdle.”

A nitpicker would mention that the bones in yellow are from a single specimen but the same 1994 paper¹  that described them also described several other bones that are known because remains of other individuals were found nearby. I would not have bothered writing this article if that was the only problem with what Sarfati has done.

The real problem is that Sarfati’s claim is false. Here is an image of a fossil remains of a single Ambulocetus, the same one that Sarfati showed with the yellow bones above:

Image is from Thewissen’s Whale Origins page called “Locomotion.”
Click here for a large high-resolution image.

Compare to the reconstruction that Sarfati objects to:

Image is mirror imaged from Thewissen’s page on Ambulocetus

There is quite a bit more to that skeleton than what Sarfati would have us believe. What Sarfati did not mention or did not know (probably the later) is that the original specimen’s locality was not completely excavated due to safety concerns when the original paper¹  of Ambulocetus by “Hans” Thewissen et. al. was published in 1994. In 1996 a great deal more of the skeleton was found. The bones found in 1996 include much of the spine and the pelvis.²  The web site for an exhibit of a reconstructed skeleton of this fossil notes that it is “missing only the tip of the snout, scapula, humerus, distal part of the tibia and some ankle bones.” In other words it is remarkably complete. (Keep in mind if one has the limb bone from left side, one knows what the equivalent limb bone on the right side looks like.) A technical description of these are in press as I write this sentence.³

There is a black and white image of the same skeleton on Dr. Thewissen’s web site that was once used instead of the above color image in his “Locomotion” that has a time stamp of June 8, 1999. Many files of Thewissen’s pages on whale origins have June, 1999 time stamps (accessed by me on October 5, 2001). The discovery of the additional bones of this fossil was mentioned in the scientific literature in 1998.² 

I suppose some readers might question if this is really only one animal. A reading of the article that AiG cited makes it clear that the find was partially articulated. Also consider a very simple set of reasonings. If the bones shown in the above image are from more than one animal then it would have been extremely unlikely that there was no duplications of bones. If they found two copies of the same bone then one must conclude that there is more than one animal represented. Given how many bones were found it is very unlikely that more than one animal is represented. Also if two animals are present they are unlikely to leave bones of a consistent size and state of preservation.

Notice that this fossil, which has a skull that paleontologists consider to clearly a whale, has what are clearly legs. In other words we have a clear transitional form; a whale that walked. The identification of Ambulocetus as whale is based mostly on the skull that has many features that are found only in whales. Michael J. Novacek of the American Museum of Natural History explains in a “News and Views” article in Nature explained:⁴ 

…Ambulocetus can be clearly allied with archaeocetes and other cetaceans [whales], based on features of the middle ear, muzzle, skull roof and teeth [references omitted]. Behind the skull, however, the specimen shows an extraordinary combination of features that anticipate, but do not fully embody, the aquatic adaptations of cetaceans. Both front and hindlimbs are well developed, with flexible elbows, wrists, knees joints and digits. The hand is large and elongate and the hind foot is huge. Toes end in the hooves as in mesonychids and other ungulates, and the tail is notably long.

Those who want details on the cetacean features of Ambulocetus should consult the technical literature.^{1,3, 5}

Sarfati accused Miller of being unreliable and yet again it is Sarfati that has turned out to be unreliable. One might excuse him that he missed a discovery that has been public knowledge and mentioned in the scientific literature at least three years. But then again he has been quite willing to repeat falsehoods that have been widely corrected for twenty years. For details on this see my “Human Lysozyme Closest to a Chicken?”

And yet this is certainly not the only nonsense from Answers in Genesis on this fossil. Don Batten wrote in AiG’s Creation Ex Nihilo Technical Journal an article called “A Whale of a Tale? (Ambulocetus).” This was published in 1994 so the author cannot be faulted for not knowing about the pelvis and vertebrae found in 1996. He wrote:

…The reconstruction of the skeleton assumes it is a ‘whale’. The authors said, ‘Little is known about the tail, but there are always many caudal vertebrae in primitive cetaceans and their relatives’ and so they sketched in a long tail for Ambulocetus! There are several paragraphs of conjecture about locomotion on land and in water and yet there is not even a pelvis or any associated vertebrae!…

Let us look at a bit more of what Thewissen et al.¹ wrote:

…Little is known about the tail, but there is always many caudal vertebrae in primitive cetaceans and their relatives [reference omitted], whereas the length of individual elements varies widely. The only caudal vertebra known for Ambulocetus is elongate, suggesting that the tail was much longer than in modern cetaceans.

Thus Batten is wrong in saying that Thewissen et al. just assumed it was a whale. Instead they based their conclusion on the fossil evidence they found. Now Batten is certainly free to disagree with reasoning used by Thewissen et al., but he should not simply say they just assumed Ambulocetus was a whale when their paper shows that they did not. Now that most of the rest of the skeleton has been found (as discussed above), we can say that Thewissen et al. were correct in their original conclusion.

Updates: Since this page was posted, AiG added a note that mentions in a rather dismissive way the more complete fossils. Notice the false claim that they were attacked for not mentioning the newer find in an 1994 published before that newer find was found. I have not seen anyone doing this. And notice that this article attacked AiG on the basis stuff that came out long after the new finds were public knowledge and noted when quoting a 1994 AiG article that "the author cannot be faulted for not knowing about the pelvis and vertebrae found in 1996."

Also since this page was posted, Thewissen and Sunil Bajpai have published a review article for nonspecialists on whale evolution called "Whale Origins as a Poster Child for Macroevolution." It is the December 2001 issue (vol. 51, no. 12), pages 1037-1049 of the magazine BioScience. For those with access to a college or university library will find it worth a look at.

Reference 3 was previously listed in this article as "in press" and "cited by reference 6." It has now been published after being in press for almost a year after being accepted for publication. This article is a technical description of parts of the skeleton that were not described by reference 5 including the pelvis.

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