The "Million-Dollar Pig's-Tooth Mystery"

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The "Hesperopithecus" tooth discovered by Harold Cook.


I could see it coming from a mile away. As soon as I heard all the hype surrounding "Ida", the exceptionally preserved specimen of Darwinius announced last week, I knew creationists would soon be citing our old friends "Archeoraptor", "Piltdown Man", and "Nebraska Man" as reasons not to trust evolutionary scientists. Each was a public embarrassment to scientists, that is true, but there is no reason to sweep these mistakes under the rug. Each can tell us something valuable about the way science works and how scientists interact with the media, and the case of "Nebraska Man" in particular has some interesting similarities to the recent hubbub over Darwinius.

It all started in 1922, a time when Christian fundamentalism was on the rise and evangelical orators like William Jennings Bryan decried the dangers of evolution. Not only did it debase our special place in the universe, they argued, but religious leaders like Bryan believed that evolutionary science had a direct role in triggering World War I. They were convinced that the leaders of Germany had imbibed the Social Darwinian Kool-Aid and were simply weeding out the unfit through war and conquest.

Bryan did not go unchallenged, however. Henry Fairfield Osborn of the American Museum of Natural History saw no conflict between Christian faith and his vision of the internally-directed course of evolution. Osborn was as appalled by Bryan's call to make a choice between faith and science as he was about Bryan's misrepresentation of evolution. As Osborn stated in his polemic response, The Earth Speaks to Bryan, he thought that;

The moral principle inherent in evolution is that nothing can be gained in this world without an effort; the ethical principle inherent in evolution is that only the best has the right to survive; the spiritual principle in evolution is the evidence of beauty, of order, and of design in the daily myriad of miracles which we owe our existence.

These principles also echo Osborn's support for eugenics, and are a combination of his unconventional views on evolution and his religious zeal. Bryan, of course, did not agree with Osborn, and the two argued through the pages of periodicals like the New York Times. Indeed, in an February 26, 1922 article published in the New York Times Bryan famously declared "truth is truth and must prevail". Osborn might have chuckled to himself when he read these words. Just the day before Osborn had received a lead about a fossil find, from Bryan's home state of Nebraska no less, that had the potential to publicly embarrass the "Great Commoner."

The letter that arrived on February 25 was from Harold Cook, a fossil hunter from Nebraska who said he had found a tooth from beds bearing other fossil mammals (like horses and antelope) "that very closely approaches the human type." (Cook had earlier tried to contact the paleontologist Frederick Loomis, but had received no response.) Osborn could hardly believe his luck, and he replied that the tooth should be sent to him immediately. He received it on March 14, and he recorded his thoughts on opening the package in a letter to Cook;

The instant your package arrived, I sat down with the tooth, in my window, and I said to myself: "It looks one hundred per cent anthropoid." I then took the tooth into Doctor Matthew's room and we have been comparing it with all the books, all the casts and all the drawings, with the conclusion that it is the last right upper molar tooth of some higher Primate, but distinct from anything hitherto described. We await, however, Doctor Gregory's verdict tomorrow morning; he certainly has an eagle eye on Primate teeth. . . . We may cool down tomorrow, but it looks to me as if the first anthropoid ape of America had been found by the one man entitled to find it, namely, Harold J. Cook!

This was not a tooth from a human, but rather seemed to represent some kind of ape. This made it all the more interesting. All the fossil apes that had been discovered came from Europe and Asia; if Cook's tooth was from an ape it would be the first fossil ape to be found in North America. Although tempted to call it "Bryopithecus after the most distinguished Primate which the State of Nebraska has thus far produced", Osborn dubbed it Hesperopithecus haroldcookii, Harold Cook's ape of the western world. Even so, Osborn was tentative in his views on Hesperopithecus. The tooth Cook found and a similar one found in the AMNH's stores was little to go on, and as Osborn wrote in the American Museum Novitates;

...it would be misleading to speak of this Hesperopithecus at present as an anthropoid ape; it is a new and independent type of Primate, and we must seek more material before we can determine its relationships.

After his initial description, however, Osborn stepped away from the scientific study of Hesperopithecus. Instead he set some of his best paleontologists, W.K. Gregory, W.D. Matthew, and Milo Hellman, to the task of figuring out what Hesperopithecus was. The analysis by the three scientists supported the ape as an intermediate offshoot between Dryopithecus, the hypothesized ancestor of the living African apes, and Sivapithecus, a fossil ape from Asia close to our own lineage. It lived in a long-lost North American world populated by rhinos, camels, elephants, horses, antelope, and a fossil peccary called Prosthennops that would soon take on greater significance to the Hesperopithecus story.

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The place of "Hesperopithecus" among other primates. "Hesperopithecus" is underlined in red.


Not everyone agreed about the identification of the teeth, however. In 1923 Gregory and Hellman wrote a second paper to defend the hypothesis that Hesperopithecus was truly a fossil ape. Other scientists who had read the earlier papers thought the teeth more likely belonged to a monkey, bear, rodent, or carnivore, and one scientist (who is not named) even proposed that Cook's tooth was truly "An incus bone [inner ear bone] of a gigantic mammal." None of these alternate interpretations seemed to hold up, though, and Gregory and Hellman upheld the status of Hesperopithecus as an ape.

To confirm this hypothesis, however, the rest of the skeleton of Hesperopithecus would have to be found. This was especially important since the original tooth was nearly destroyed. In an interview Gregory later gave to Popular Science in 1931 the anthropologist referred to the whole event as the "million-dollar pig-tooth mystery", the "million-dollar" aspect coming from when the tooth was going to be x-rayed. When Gregory handed the tooth to the x-ray operator he jokingly told him to be careful for the specimen was worth a million dollars. The man became so nervous that he dropped it, and it shattered into bits which Gregory had to collect and later glue together.

Hence the search for more Hesperopithecus fossils became more important than before. The area from which Cook found the first tooth were searched but no more of Hesperopithecus turned up. Instead Gregory and the other workers who picked over the site found more remains of Prosthennops, and Gregory was shocked to find that the teeth of this ancient pig-like animal matched those of Hesperopithecus perfectly. In 1927 Gregory published a letter in Science in which he announced the downfall of the "western ape";

Last summer (1927) Mr. Thomson made further excavations in the exact locality where the type of Hesperopithecus haroldcookii was discovered. A number of scattered upper and lower premolar and molar teeth were found in different spots, but every one of them appears to me to pertain to Prosthennops, and some of these also resemble the type of Hesperopithecus, except that the crown is less worn. Thus it seems to me far more probable that we were formerly deceived by the resemblances of the much worn type to equally worn chimpanzee molars than that the type is really a unique token of the presence of anthropoids in North America.

This was a very embarrassing situation, but sometimes hypotheses turn out to be wrong. Within the space of five years scientists formed a hypothesis about a tooth, knew they required more information to fully understand it, and sent out field workers to find more bones to test their idea. This is how science works. Also, as Gregory would later state, it was probably just as well that they were wrong. If they had found an ape closely related to humans from North America it would have confused efforts to understand our ancestry; it would have thrown anthropologists off the track and have them searching North America in vain. Why, then, do creationists continue to mention "Hesperopithecus" as a case of science gone awry?

Much like the present controversy over "Ida", the scientific statements about "Hesperopithecus" did not match how the creature was presented to the public. First, Osborn could not contain his excitement over finding what he thought was a fossil ape from Nebraska. How could Bryan deny evolution when one of our relatives used to inhabit his home state? It was such a fortuitous find that Osborn could hardly control his enthusiasm and in The Earth Speaks to Bryan he wrote;

It is noteworthy that shortly after his pledge to accept the Truth appeared in 1922 ["truth is truth and must prevail." - Bryan in the New York Times, Feb. 26, 1922], the Earth spoke to Bryan and spoke from his own native State of Nebraska, in the message of a diminutive tooth, the herald of our knowledge of anthropoid apes in America. This Hesperopithecus tooth is like the "still small voice"; its sound is by no means easy to hear. Like the hieroglyphics of Egypt, it requires a Rosetta Stone to give the key to interpretation. Our Rosette Stone is comparison with all the similar grinding teeth known, collected from all parts of the world, and described or figured in learned books and illustrations. By these means this little tooth speaks volumes of truth-truth consistent with all we have known before, with all that we have found elsewhere. [emphasis mine]

Unfortunately the right "Rosetta Stone" to understand "Hesperopithecus" was a fossil peccary, and Osborn was so abashed by his blunder that he never mentioned "Hesperopithecus" again. Yet this does not explain why creationists still go on and on about "Nebraska Man." Osborn never applied the title to the teeth and he had maintained that "Hesperopithecus" was a non-human ape from the very start. Where did "Nebraska Man" come from?

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"Nebraska Man" and wife. From the Illustrated London News.


Shortly after the announcement of "Hesperopithecus" in 1922 the Illustrated London News ran an article about the find by Grafton Elliot Smith. Included with it was a restoration of what "Hesperopithecus" might have been like by Amedee Forestier, but it was a far cry from what Osborn, Gregory, Matthew, and Hellman envisioned. Forestier, taking inspiration from depictions of "Java Man" (known as Homo erectus today), turned "Hesperopithecus" into "Nebraska Man." He is seen walking, club in hand and "wife" by his side, through a landscape inhabited by camels and other prehistoric mammals.

Osborn was not happy about this. So little was known of "Hesperopithecus" at the time that "such a drawing or 'reconstruction' would doubtless be only a figment of the imagination of no scientific value, and undoubtedly inaccurate." Smith, though, thought that Forestier's painting hit pretty close to the mark. Contrary to the findings of the AMNH team Smith thought that "Hesperopithecus" might have been "a primitive member of the Human Family." Smith's thoughts on "Hesperopithecus" aside, "Nebraska Man" was never a scientific idea, only a speculation of what might be by Forestier.

The rise and fall of "Hesperopithecus", then, cannot be represented by a single thread. It is a complex story where there was little agreement about the tooth from Nebraska until the issue was finally settled in 1927. The scientists who first described the teeth thought that it was a North American ape, not a fossil human, but the Illustrated London News painting stuck more firmly in the minds of people than the actual scientific discussions about the fossil. Will it be the same with "Ida"? Will the media hype overshadow scientific discussions about her exquisitely-preserved bones? Only time will tell, but at least in this case Darwinius is represented by a nearly-complete fossil. "Ida" is most definitely a fossil primate, and I look forward to the forthcoming debates over where she fits in the primate family tree.

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Osborn:

The moral principle inherent in evolution is that nothing can be gained in this world without an effort; the ethical principle inherent in evolution is that only the best has the right to survive;

Tapeworms are well known for their industry and upstanding moral character.

Well said, hope this turns out better. In the BBC documentary, Attenborough closes with the revelation that Ida has a Talus bone shaped like that of monkeys, apes and humans, while prosimians such as lemurs have a completely different shape, proving that Ida was one of us. A minor problem, as a layman I can't find any sign of this amazing proof in the PLoS ONE paper. Did you see it?

A related issue is that it's really hard to get a grasp of the various phylogenic trees being proposed, and to add to the fun there seems to be a dispute as to whether Anthropoidea should really be called Simiiformes, or indeed what's included under each name. Your "poor, poor Ida" post is very helpful, any further clarification will be welcome.

By dave souza (not verified) on 27 May 2009 #permalink

Dave; Yes, the cladistics for this are very complicated. A basic overview can be seen in Chris Beard's editorial about Ida from last week at New Scientist. I will try to work up something of my own soon to explain how Ida fits into the larger debate.

As for the talus issue, Afarensis just posted something about it. it is in the paper, but strangely it is not illustrated. The short story, though, is that it may or may not be very important to Ida's status. Lots of groups outside primates share a similar talus shape so it could very well be a case of convergence. Further study will be needed, but I find it interesting that earlier in the week we were hearing all about toilet claws and tooth combs and now it's all about the talus.

From a creationist critique of a biology textbook used in South Carolina:

The Nebraska man used previously to show descent of man was fabricated from one tooth in 1922. And this tooth was proven to be an extinct pigâs tooth and in 1972 the extinct pig was found to demonstrate a fraud used to promote the evolutionary worldview point in textbooks for 50 years.

Note the "mistake" of "1972" for "1927" giving rise to "50 years" when it should have been "5 years"--and of course the false claim that Nebraska Man was "a fraud used to promote the evolutionary worldview point in textbooks".

Thanks for another great article on one of the obscurer incidents in the history of science. It's a genuinely interesting story, especially taking into account the personalities and politics of the time. William Jennings Bryan is a favorite character of mine, a walking mass of contradictions clearly invented for a satirical novel rather than a figure out of sober history.

Most interesting to me is that everyone says "talus" instead of "astragalus". Is that the human nomenclature or something?

By David MarjanoviÄ (not verified) on 27 May 2009 #permalink

David; Yup, that's the name I learned for it in human osteology. I am not sure if it is typically used just for humans or just for primates, but it is an interesting point.

What makes Ida quite different from 'Nebraska Man' - or Ramapithecus - is that is very complete and hence its flesh reconstruction is probably fairly accurate. The similarity to these is the media hype. The idea that Ida is a very early and crucial supposed ancestor does remind me of Ramapithecus. But never did I imagine that a prosimian would be the center of hype storm.

Thanks for the links and pointing out where to find the talus in the paper â I did try searching for talus and astragalus, but epic fail. Now I know it's there, and it's just that it's over my head. The odd thing is that their Table 3 shows a grand total of 6 synapomorphies, three of which including "21. Relatively small, steep tibular facet on astragalus" are shown as shared with "Tar". So, it's got tarsier features.

It actually appears in the press release dated 19th May, downloadable from the otherwise uninformative flash loaded "Link" website. Two paragraphs after a paragraph about the tooth comb and the grooming claw differentiating Ida from lemurs, a paragraph starts with "Evidence in the talus bone links Ida to us. The bone has the same shape as in humans today. Only the human talus is obviously bigger." then goes on to the evidence that she was immature and female. Not quite as much impact as the dramatic climax to the TV programme.

By dave souza (not verified) on 27 May 2009 #permalink

Colugo; Yes, I did try to drive that home towards the end. The part that the "Hesperopithecus" farrago that most reminded me of this Ida business, though, was that different sources have had very different interpretations; the paper says something different from what the author is saying which is different from what some of the media is saying. It's just a mess. A year from now I'll have to write a follow-up about how things have turned out for Ida.

Interesting comparison! So the moral of the story is that humility in human knowledge is a good idea as we test it and expand it, that sensationalism is ultimately damaging to it, and that unfortunately kids are exposed to textbooks that promote fake facts.

Textbooks do include false facts; no rabbits in South America, Dimetridon is a dinosaur, etc. I don't think any of this is intentional. Particularly in a general introductory text, it is difficult to get the right reviewer on every issue. I have long thought that introductory textbooks should intentionally include false facts. Otherwise why do we need cosmically knowledgable Distinguished Full Professors teaching introductory classes? The virtue of false facts is that the teacher can document for the student that the facts are false, and thus decrease the students' unquestioning acceptance of the written word. If textbooks were perfect, we could just give a rotating group of students $10/hr to stand in front of the class and read them aloud.

By Jim Thomerson (not verified) on 27 May 2009 #permalink

You make some valid and important points about the Hesperopithecus incident that are relevant to the current situation.

There was far from universal acceptance in the scientific community of Hesperopithecus as a potential human ancestor, but the fact is that in the public view it was seen as such. That public view didn't just happen, it was the result of the staements made by scientists at the time, and the spin put on it in the popular press and publications. While the text book referred to in (4) certainly overstates the case when it referrs to 50 years, the fact is that Hesperopithecus was turning up in books and popular works as being of significance to human evolution long after the truth was known to the scientific community. Once the wrong message was put over it seemed to be very difficult to undo.

With Ida the public perception is apparently very different to that of the majority of the scientific community. Friends who are not scientists, and who usually have no interest in science, have been talking about this and they have accepted the hype as served up. I have suggested to some that they read the paper for themsleves, and check out the comments on on-line blogs such as this, but the reaction of one of them sums it up, he said I watch documentaries such as David attenboroughs so I don't have to read stuff like that (I paraphrase him of course). On some internet blogs there are descriptions of Ida as the 'new Lucy', as the end of religion, etc etc. I am really disappointed in the TV documentary which seems to just add to the one-sided presentation and misconceptions. I just hope it won't take decades to correct the view.

But lets not lose sight of the real significance of Ida - an amazingly beautiful and informative fossil, that gives us the best insight yet to the biology and lifestyle of adapids.

Well done! This will now be my standard reference in response to creationists still humping Nebraska Man. That it does double duty countering the all-but-certain exploitation of the Ida hoopla by creationists is a bonus.

John; Thanks! This was meant as a repost, but I decided to write it over again from scratch. I thought it was very interesting that Hesperopithecus was interpreted in so many different ways by some many different people, and wanted to make it clear that "Nebraska Man" was never a scientific concept.

Corax; Indeed, Ida is wonderful, and I am looking forward to further studies of her by other scientists like Beard, Kay, Ross, Symons, etc.

The reactions you describe are precisely the kind I was concerned about. Even with the skeptical treatment of the "missing link" claims I have seen in many UK papers and the NYT it is difficult to overcome the hype. The History Channel, like it or not, is a trusted source for science among many people, and no matter how many blog posts or op-eds I write I just can't compete.

I was also a little disturbed by Hurum's reluctance to engage the scientific community over the claims he has made about Ida. He seems to have had a key role in organizing this whole PR mess yet he admits he is not a primate expert and he has no intention of going to conferences where he could talk to other scientists about the find (he would rather just read papers he's interested in, he says). Perhaps my worries are unfounded, but I am concerned that access to Ida is going to be restricted and it might take years for another team to get access and do some competing research.

Really, very interesting topic. If possible, please more information. This is one of the better blogs that I read.

Colugo; Yes, I did try to drive that home towards the end. The part that the "Hesperopithecus" farrago that most reminded me of this Ida business, though, was that different sources have had very different interpretations; the paper says something different from what the author is saying which is different from what some of the media is saying. It's just a mess. A year from now I'll have to write a follow-up about how things have turned out for Ida.