It seems that almost every time a new fossil primate is announced the first question everyone asks is "Is it one of our ancestors?" Nevermind that it is all but impossible to identify direct ancestors and descendants in the vertebrate fossil record (including primates). If the fossil can be construed to be a human ancestor it gets plenty of attention and if it is not the reports are left to wither. For a primate fossil to be seen, it must be promoted, and this often leads overblown reports. Such is the case with a new fossil anthropoid from Myanmar described by an international team of scientists today in the Proceedings of the Royal Society B.
When I fired up my computer this morning I was greeted by attention-grabbing headlines that proclaimed "Early Man Evolved in Burma", "Human, Ape Ancestor Hails From Asia", and "Rival Fossil Challenges 'Missing Link.'" The hype was not quite as intense as that which surrounded the lemur-like "Ida", but all this hullabaloo suggested that this new primate would tell us something significant about our own origins within the primate family tree.
After I actually read the paper I could only assume that this is yet another case of media outlets blindly swallowing press releases that overplay controversy and obscure the true significance of fossils. There is nothing in the paper to suggest that this new fossil anthropoid, named Ganlea megacania, is one of our ancestors or a common ancestor of monkeys and apes. It is only being marketed as a competitor with "Ida" to get it more attention; who would otherwise care about a 38-million-year-old seed-eating monkey?
Before I delve more deeply into the misinformation being promulgated about Ganlea, though, let me discuss what the paper actually says. During the past several decades paleontologists have been finding the fragmentary remains of a group of extinct primates called amphipithecids from Myanmar and a few other localities in Asia. There has been some debate as to how they might relate to each other and other primates in general. Some scientists have seen them as anthropoids (the group that contains monkeys and apes) or as adapiforms (an extinct group of lemur-like primates that includes "Ida"). Ganlea helps to resolve some of these relationships.
So far Ganlea is only represented by some jaw fragments and assorted teeth, but a mammal's teeth can tell you a lot. The teeth of Ganlea clearly group it with other amphipithecid primates from the area like Myanmarpithecus and Podaungia, and together these primates appear to belong to a monophyletic group (or they all shared a recent common ancestor and are closely related). Indeed, one key trait shared among these primates is a canine tooth that is compressed front-to-back so that it is wider than it is long. This and other minute details of the teeth appear to be unique characteristics of this group.
So how do the amphipithecids relate to other primates? The cladistic analysis undertaken by the scientists found that these primates were closely related to New World monkeys (platyrrhines) and an extinct group of anthropoid primates called propliopithecids (represented by creatures like Aegyptopithecus from the Fayum region of Egypt). Which of the two groups the amphipithecids were more closely related to is as yet uncertain, but this placement means that that the amphipithecids were anthropoid primates, not adapiforms. If were able to see Ganlena and its close relatives in life they might resemble living monkeys.
Indeed, the amphipithecids do not sit near the base of the anthropoid evolutionary bush, like the fossil primate Eosimias, but are more evolutionarily specialized. More fossil material will have to be discovered to further compare Ganlea and other amphipithecids to other fossil anthropoids to further test the hypotheses of the authors. (See this post for the difficulties in tracing primate evolution based upon jaws and teeth alone.)
What is particularly interesting about Ganlea, though, is that it had a huge canine tooth (hence the species name "megacania") that looks as if it was shaved down at a steep angle. This was not a break, but a particularly intense case of tooth wear. What could have caused this? The authors proposed that Ganlea (as well as the other amphipithecids) often fed on hard seeds and nuts that abraded the canines of these primates. The large lower canines of Ganlea, in particular, might have been an adaptation to this particular feeding niche represented today by saki monkeys of Central and South America.
To sum things up, then, Ganlea was a fossil anthropoid primate that was possibly closely related to New World monkeys and often fed on seeds and tough-skinned fruit. Depending upon whether it turns out to be more closely related to New World monkeys or the extinct propliopithecids, it could help paleontologists understand the evolution and dispersal of monkeys throughout the world. Why, then, is is being touted as proof that the early evolution of our own lineage began in Asia?
The first report I saw, kindly sent to me by Karen, claimed that Ganlea represented the "ultimate ancestral group of all anthropoids," thus making it one of our ancestors. Since humans are apes, and apes are anthropoid primates, the last common ancestor of all anthropoids would be one of our distant primate ancestors. Ganlea, though, may be more closely related to New World monkeys, a branch of the primate family tree that did not give rise to apes or humans. Perhaps some of the confusion came from this quote from Christopher Beard, one of the authors of the description of Ganlea, in which he compares Ganlea to "Ida";
Ida is a complete fossil, and that in many ways is its calling card. We have an incomplete fossil of Ganlea but even though it is not complete, its anatomy is far more compelling for it to be the ancestor of monkeys, apes and humans than it is for Ida to be the ancestor.
Given that Ganlea is an anthropoid it is likely more closely related to us than Darwinius ("Ida"), but if the analysis of Beard et al. is correct then it is far too specialized to be considered the common ancestor of anthropoid primates. If we had to choose between Ganlea and Darwinius alone for which better represents the last common ancestor of all anthropoids Ganlea would probably win, but since this is not the case Beard's quote all-too-easily creates confusion. Furthermore, there is a lot of irony in Beard's remark that;
Ida is a good-looking fossil but it was the victim of incredible marketing. It is not all that it was cracked up to be. I've never seen such hyperbole surrounding a primate fossil as the one that came with Ida - and I'm not alone in thinking that.
The same, to a lesser degree, could be said about Ganlea. The press release about Ganlea plays up its supposed relevance to the origin of anthropoid primates in Asia, a debate which Beard has been steeped in since his involvement in the description of Eosimias in 1994, but these statements stand in stark contrast to what is actually contained in the paper. I am sorry to say so, but the press office of the Carnegie Museum of Natural History has misled the public about what the paper describing Ganlea says and its relevance to primate evolution. Despite the complaints about the hype surrounding "Ida", they are marketing Ganlea in a similar way.
This is extremely unfortunate as the statements of the press release have been echoed without skepticism in many reports. I can only assume that almost no one has actually read the paper as each of the stories I have seen couches the actual details of the paper within the "Monkeys/Apes/Humans evolved in Asia and migrated into Africa" issue. This is a huge mess of a misunderstanding the press release played right into. Examples include the The Irrawaddy, ScientificBlogging, the Science Codex, the Pittsburgh Tribune Review, Discovery News, and MSNBC. The Pittsburgh Tribute Review is particularly confused. It starts off by saying;
An international team including a Pittsburgh researcher announced Tuesday it discovered a fossil in Myanmar that challenges the popular theory that humans evolved from a primate in Africa.
This is so vague that it can be easily misunderstood as saying that the earliest humans did not evolve in Africa, but it is contradicted further down: "This does not mean that humans evolved in Asia, Beard said." I know what the reporter probably means, but I don't think the average reader will have the background information to adequately parse these statements (which are the ones likely to gain the most attention). Beard has done a lot of work popularizing the idea that anthropoids first evolved in Asia, not Africa (see Hunt for the Dawn Monkey), but that is another story that Ganlea is only peripheral to. Ganlea might be important in figuring out the origins of New World Monkeys, but it does not overturn the notion that hominins originated in Africa.
Press releases and public relations announcements are skewing how Ganlea is being presented. The information being passed on to the public is being overblown to attract a wider audience, and this obscures the real scientific significance of the discovery. Indeed, the sites listed above are not engaging in journalism. They are simply parroting what they are being told because the reporters apparently do not have enough experience to read or understand the scientific research itself.
Some might argue that sensationalist headlines and hyped-up claims help bring in wider audiences, and while that is true it does not do any good if you end up confusing the people you are trying to educate. Trying to one-up other discoveries with impressive-sounding, but vague, pronouncements can be hazardous in that members of the public can be given misleading information (i.e. that humans did not evolve in Africa). People are going to remember the hook more than the details, and this is unfortunate when your hook is not accurate. If this represents standard practice in modern science communication among news outlets, we are in a helluva lot of trouble.
K. Christopher Beard, Laurent Marivaux, Yaowalak Chaimanee, Jean-Jacques Jaeger, Bernard Marandat, Paul Tafforeau, Aung Naing Soe, Soe Thura Tun and Aung Aung Kyaw (2009). A new primate from the Eocene Pondaung Formation of Myanmar and the monophyly of Burmese amphipithecids Proceedings of the Royal Society B DOI: 10.1098/rspb.2009.0836
- Log in to post comments
Interesting story, marred by the "missing link" comparisons with "Ida". There's a lot of irony in the AP story, with Chris Beard making bold claims suggesting anthropoids having a common ancestor in Asia, and Jorn Hurum saying that it was too early to draw conclusions from the Myanmar fossils â complete role reversal.
http://www.google.com/hostednews/ap/article/ALeqM5jfBpw9sw_qIrKFzUzGHNH…
Nice to see that the paper is free online, and while it's mostly over my head, it's noticeable that the phylogenetic analysis is based on a data matrix including 39 taxa and 326 characters â can a comparison be drawn with the Darwinius analysis which apparently compared only 30 traits?
Let me try and cut through some of the early confusion related to our publication describing Ganlea megacanina, a 38 million year old amphipithecid primate from Myanmar. Brian's summary of the anatomy of Ganlea is spot on, and my coauthors and I also appreciate his accurate reporting on how we have tried to reconstruct the distinctive ecology of this species and closely related amphipithecids from Southeast Asia. Remarkably, these early Asian anthropoids appear to be very close ecological analogues of living pitheciin monkeys (including the modern genera Pithecia, Chiropotes, and Cacajao), which inhabit the Amazon Basin and adjacent areas.
The main point of contention here is the phylogenetic position of Ganlea and its relatives with respect to other living and fossil primates (and the related issue of how this is being portrayed in the popular press). Our fairly detailed phylogenetic analysis, which we invite readers to compare with the far more rudimentary work performed on the fossil primate "Ida," indicates that Ganlea and other amphipithecids are nested within the clade that includes living New World and Old World anthropoid primates (as well as the extinct Propliopithecidae, which are unanimously regarded as early catarrhines, or Old World anthropoids, by primate paleontologists). Anatomical evidence for amphipithecids is so far restricted to data from the teeth and jaws and one ankle bone--the astragalus (= talus of human anatomy). Despite this paucity of anatomical evidence, amphipithecids appear to be relatively derived anthropoids or "crown anthropoids" in the jargon of some systematic biologists. Parenthetically, what little we can infer of amphipithecid behavior appears to be distinctly anthropoid-like too, in that they appear to have been specialized seed predators, unlike any living or fossil "prosimian" primates (the latter term is, of course, a paraphyletic grouping akin to "reptiles" or "amphibians"). Yet, amphipithecids are older than any well-documented anthropoid primates known from Africa, probably by about 3 million years. Disparity in the age of the earliest records of a given taxon in different places is one criterion for reconstructing historical biogeography, and the antiquity of Ganlea and other amphipithecids is therefore consistent with an Asian origin for Anthropoidea as a whole.
More compelling evidence that anthropoids arose in Asia comes from more basal taxa of anthropoids, such as Eosimias and its close relatives (including Bahinia, which lived alongside Ganlea in Myanmar 38 million years ago). Eosimiids are "stem anthropoids," meaning that they occur on the root of the anthropoid family tree. All living anthropoids, and presumably Ganlea, shared a single common ancestor for some unknown interval of time after Eosimias and its relatives had diverged evolutionarily. Eosimiids are so far only known from Asia. Their basal phylogenetic position with respect to "crown anthropoids" and their great antiquity (~45 million years) provides especially compelling evidence for an Asian origin for Anthropoidea.
The final piece of evidence for reconstructing the continental birthplace of anthropoids comes from the living sister taxon of Anthropoidea, which consists of modern tarsiers. Tarsiers are currently restricted to islands belonging to the Philippine archipelago and the eastern part of Indonesia (as well as northern Borneo, which is politically part of Malaysia and Brunei). Fossil tarsiers have been found on the Asian mainland, but never in Africa (Afrotarsius from the Fayum region of Egypt is misnamed--it is almost certainly an early anthropoid and not a tarsier). By definition, the anthropoid lineage (or clade) originated when it split apart from the lineage leading to modern tarsiers. Given the geographic restriction of tarsiers, anyone who wishes to argue that anthropoids originated someplace other than Asia has to explain why tarsiers are currently endemic to that landmass (as well as the distribution of fossil taxa like eosimiids and amphipithecids).
Summarizing all of the above, we believe that the evidence is now at least compelling, if not overwhelming, that anthropoids originated in Asia, and the press release from the Carnegie Museum of Natural History reflects this conclusion.
Have some science journalists made the mistake (or oversimplified the story) by claiming that Ganlea shows that humans originated in Asia? Perhaps. But I have consistently tried to emphasize that our data are irrelevant to reconstructing human origins per se, while these same data are critical for reconstructing anthropoid origins. Of course, depending on your time frame and taxonomic latitude, anthropoid origins is human origins writ large.
As far as the comparisons to Ida are concerned, our paper serves as a useful reminder that Ida really is only very peripherally related to anthropoids, as Figure 4 in our paper documents (Ida belongs to the Notharctidae in that figure). So don't worry too much about the level of "hype" related to Ganlea: we don't have a book deal, there is no TV documentary, and the only marketing behind our effort is that provided by the Carnegie Museum of Natural History and our collaborating scientific institutions, like CNRS in France.
Chris; Thank you for your comment here. I enjoyed that paper and thought the analysis of Ganlea was well done. Likewise, the only quote of yours I thought was a little too fuzzy was the one I mentioned above and I certainly do not blame you personally for what was presented in the mass media.
That being said, I think the way this story is being reported is causing a lot of confusion. If more discussion of Eosimias, &c. were included it might make some sense to talk about the origins of anthropoids in Asia, but I did not see the real connection with Ganlea. I think the conclusions of your paper were interesting enough by themselves that they did not have to be overhyped and contribute to what I think is a media model that focuses on "Was this primate our ancestor or not?" As I stated above, I think we run the risk of the hype overshadowing the facts unless we take great care to explain what we mean and put things in context.
Again, I thought the paper was wonderful, but the media coverage (based upon the press release) really got on my nerves.
Spot on for the most part. I think one of Beard's stronger argument both with this new discovery, Eosimias, and tarsiers, is that one would expect the greatest diversity of anthropoid primates closer to where they originally evolved. It is unlikely that new world monkeys (which seem to be related to Ganlea), tarsiers, eosimias, and other primitive forms of the primates we see today evolved elsewhere, then all moved to Asia (and some like the tarsier are only found in Asia). Rather, Beard is suggesting that the diversity of ancient primate forms in Asia, being home to earlier anthropoids, tarsiers, and now new world monkeys, makes the out of Asia scenario more compelling.
The Burmese junta has actually been trying to claim Burma as the seat of human evolution for a while. Check out this older article from the government-run newspaper:
http://www.myanmar.gov.mm/Article/Article2003/feb/feb4d.html
Of course, the region where many of these paleontological discoveries have been made (the Chin Hills) is a disaster with widespread famine. But that's another story.
Chris; Also, I did not mean to offend by using the words "hype" and "marketing." The latter term, particularly, I was thinking of in terms of "selling" the importance of new discoveries to popular audiences. Yes, Ganlea does not have a book, website, &c. behind it, but when I run a Google search it is most often presented as a competitor for "Ida" as the common ancestor of later anthropoids. Again, this is not your fault, but it is something I am concerned about since that thread of the story is superseding everything else.
Dom: Quite right, and I agree that Ganlea adds to that case. It just wasn't in the paper and that aspect of it is not being addressed publicly. Instead it is being shown as a competitor for the "last common ancestor" throne. That is the part that concerns me, but I fear we are stuck with this sort of "ancestor worship" in the popular press.
Ganlea is known only from a jaw and teeth. It differs from Darwinius, to the limited extent they can be compared, in having a fat canine. How does this make Ganlea a common ancestor of monkeys, apes, and humans, and how does this make Darwinius a lemur (in the view of K. Christopher Beard and the Carnegie Museum of Natural History)? Sounds like 'My fossils are anthropoids, your fossils are lemurs ... because I say so!'
Given the fossils we know of Ganlea and Darwinius, both look like adapoids: haplorhines, yes; anthropoids, possibly some relationship; lemurs, an outdated assertion with no supporting evidence (strepsirrhine lemurs and lorises aren't included in the Ganlea cladogram).
Philip:
First off, Ganlea differs from Darwinius in many more ways than simply having a fat canine. Take a closer look at, among other characters, mandibular depth, angle of incisor implantation, oblique orientation of the lower premolars in the jaw, upper and lower premolar morphology, and upper and lower molar morphology. Aside from both taxa being primates, I see very little that they share in common, and no reason to regard them both as "adapoids." By the way, if anything is an adapoid, Adapis is, and we tested and rejected the hypothesis that Ganlea is closely related to Adapis in our paper (see our Figure 4).
Another important point made by our paper (see the title) was the novel demonstration that all Burmese amphipithecids, including Myanmarpithecus, are monophyletic. Late last year, you coauthored a paper with Gunnell and multiple other authors in which you stated in passing that Myanmarpithecus was a "probable omomyiform." Have you now changed your mind, so that Myanmarpithecus is now an adapiform, along with all the other amphipithecids? If so, you are the first person (to my knowledge) to make this case, and I would be interested in learning about the morphological support for it.
I'm sorry Darwinius didn't pan out the way it was portrayed on the History Channel, but simply having a relatively complete fossil does not give anyone the right to assert it is something it clearly is not.
Phylogenetic analyses in two papers that I lead-authored in 2005 (Seiffert et al., 2005, Science, v. 310, pp. 300-304 and Seiffert et al., 2005, PNAS, v. 102, pp. 11396-11401) also showed, based on more characters and more taxa, that Myanmarpithecus, Amphipithecus, and Pondaungia form a clade to the exclusion of Siamopithecus. These papers were not cited in the description of Ganlea. Therefore I would take issue with the claim that "another important point...was the novel demonstration that all Burmese amphipithecids, including Myanmarpithecus, are monophyletic".
"Some might argue that sensationalist headlines and hyped-up claims help bring in wider audiences, and while that is true it does not do any good if you end up confusing the people you are trying to educate"
Where on Earth did you get the impression that journalism is about educating people?! (Note: don't confuse "what ought to be" with " what is"!)
We live in a capitalist economy and it's about making money, staying in business, growing business. In order to make money you need advertisers and in order to get those, you need readers. Apparently the only way they can see towards maintaining and increasing readership is to be more sensationalist than the other guy.
Even scientists, especially in anthropological and closely-related sciences are, in effect, in a capitalistic environment since they compete for grant money.
That's why the smartest of us rely on people like you to break through the scum floating on the surface and expose the clear and refreshing waters below.
Thank you!
What I great discussion! As much as I respect Phil for all of his prior achievements, I hope that he's learned something from the media circus and the exaggerated claims that accompanied it. I didn't think the paper was all that bad (although it could have been much, much better), but the tacit agreement with all of the ridiculous claims in the book/website/documentary is what provided the biggest hit the reputations of all involved.
I work a bit with Phil, so it's in my interests that he not be too damaged by all of this. Hopefully his recent work on Maiacetus, among various others, can be what people remember.