Recently in Transitional Fossils Category

A common bleat from creationists is “Where are the millions of transitional fossils Darwin said there should be?” Martin Brazeau has an excellent post on taphonomy at The Lancelet reporting a paper in which folks let poor innocent critters rot in order to ascertain which anatomical features are likely to be preserved and which are likely to be lost before fossilization, and the implications for interpreting fossils of ‘soft’ tissues for phylogenetics. Comment there, please.

Creationists are always very definite that there are absolutely, absolutely no transitional fossils between apes and humans. For example, according to a 1990 article by Answers In Genesis (AIG)

When complete fossils are found, they are easy to assign clearly as either ‘ape’ or human, there are only ‘ape-men’ where imagination colored by belief in evolution is applied to fragmented bits and pieces.

Very well then. Here are some photos of fossil skulls, all to the same scale. Some are of humans, some of apes. Care to identify which are which?

Answers after the fold.

By Don Prothero http://faculty.oxy.edu/prothero/index.htm

Don Prothero is a paleontologist and Professor of Geology at Occidental College in Los Angeles, and Lecturer in Geobiology at the California Institute of Technology in Pasadena, and author of Evolution: What the Fossils Say and Why it Matters, in my opinion the very best book on fossils and evolution for the general reader. Last night, Monday, November 30, Prothero debated (along with Michael Shermer) ID advocates Stephen Meyer (longtime head of the Discovery Institute’s Center for the Renewal of Science and Culture) and Richard von Sternberg (the former editor who in 2004 published Meyer’s pro-ID article in the last issue of the Proceedings of the Biological Society of Washington (D.C.) which Sternberg was scheduled to edit, despite the article being wildly off-topic for an alpha taxonomy journal, substantially copied from other Meyer publications, badly inaccurate, and just weird in several ways). Sternberg is now, I believe, an employee of the Discovery Institute.

Prothero wrote these remarks directly after the debate and emailed them to me. I have added links where relevant. — Nick Matzke

My mind is a bit fuzzy from the loss of sleep, and the two hours of “debate” went by very quickly, so I cannot recall all the details, let alone recount them. Here are my morning-after thoughts about last night’s “Battle in Beverly Hills.” I don’t know when they’ll release the video recording of the event, but when it does come out, hopefully it will be possible to post it so you can all see for yourself how it went. My subjective summary of it is that our side did very well: I caught them off-guard with new arguments they had no answer for; Shermer pushed them hard repeatedly to state who the “Designer” was (and Meyer finally conceded it was God), while we both pushed them hard on the fact that neither of them ever addressed the topic of the debate, “Origins of Life.” I could tell that they were rattled a number of times, and I definitely shook up Meyer and got under his skin with my answers. Several times Meyer and Sternberg were arguing with each other, leaving the moderator, our side, and the audience wondering who runs their show. The best sign of my effect on them was Meyer trying to challenge MY credentials, or dodging a tough question by playing the sympathy card and calling me “condescending” — and the virulent post on the Discovery Institute site this morning, full of lies and spin. Of course, the event is staged so that no one will really “win”. Their supporters turned out and dominated the audience, but I had a LOT of people come up to me during the book signing (we sold a LOT of books) and congratulate me, or discuss points further with me. And we got just as much applause and sympathetic laughter at our well-turned phrases as they did.

As a last treat for the 150^th anniversary of the Origin, have a look at young-earth creationist creationist Cornelius Hunter [Update: Hunter has stated he is not a young-earth creationist on his blog, so I guess he’s not, although that position directly follows from his stated theology/philosophy], author of the “Darwin’s God” book and blog. Hunter’s basic argument against virtually any common pro-evolution argument is, basically, “But you evolutionists are claiming that God wouldn’t have done it this way! You’re making an unscientific theological argument!”

As Matt Young pointed out recently, the fifteen year wait for the complete publication of the Ardipithecus ramidus skeletal material discovered by Tim White, and his research group, is over. The material was finally published in Science and is open access. I will discuss the morphology of Ardipithecus ramidus and its implications in a second post. In this post I would like to look at the geological, environmental, and taphonomic background to the discoveries. I examine these first because they provide strong evidence to back up some of the behavioral interpretations of Ardipithecus ramidus.

The English media is full of articles about the Dmanisi fossils, based on a talk by David Lordkipanidze at the British Science Festival. The articles mention the discovery of five or six specimens, with some giving the impression that these are new discoveries. The New Scientist commented that “it’s not clear whether Lordkipanidze was presenting new data, or simply wrapping up the story so far for a more lay audience at the festival.” However some of the other newspapers such as the Guardian clarified that most of these fossils were discovered early this decade, along with another recent discovery that is not yet published. According to The Times, this recent find is “a fifth well-preserved skull, the most complete yet”, which will make it a spectacular fossil. This is probably the specimen shown a photo in many of the articles, still half-embedded in rock.

As is usual, a number of newspapers somewhat overstated the significance of the find, especially the Daily Mail with its headline “Ancient skeletons discovered in Georgia threaten to overturn the theory of human evolution”. This is highly misleading. The Dmanisi fossils are a tremendous discovery, and may well change our ideas about some details of where, when, and how we evolved, but they’re certainly not going to overturn the idea of human evolution. They are actually superb evidence for human evolution.

The Dmanisi hominids are from the country of Georgia (http://www.talkorigins.org/faqs/homs/d2700.html). A number of skulls have been found so far, ranging from about 850 cc (the lower end of the H. erectus range) down to 600 cc (well into the H. habilis range). In 2007, details of some skeletal material was published.

The brain sizes of these skulls straddle the gap that creationists like to claim exists between humans and australopithecines. The skulls are also intermediate anatomically, looking like primitive H. erectus skulls with some habilis features. The same is true of the skeletal material: the creatures were indisputably bipedal, but have a number of primitive features.

Naturally, creationists don’t have a clue what these fossils are. Some of them think they’re humans, some think they’re apes, and, as I blogged last year, they’re both wrong:

Dmanisi fossils - more transitional than ever
Dmanisi and Answers in Genesis

Note: In the initial version of this post, I thought the articles were referring to new fossil discoveries, which turned out to be (mostly) not the case, so the post has been corrected accordingly.

This is an important new fossil, a 47 million year old primate nicknamed Ida. She’s a female juvenile who was probably caught in a toxic gas cloud from a volcanic lake, and her body settled into the soft sediments of the lake, where she was buried undisturbed.

What’s so cool about it?

A recent paper (Bennett et al. 2009) announced the discovery of 1.5 million year old fossilized footprints from Ileret, Kenya, almost certainly belonging to Homo erectus (see also this commentary article by Ann Gibbons). Homo erectus was already known from fossils such as the Turkana Boy to be very similar to modern humans below the neck, and completely adapted to bipedal locomotion. So it was no suprise when the footprint analysis showed that the owners of the Ileret footprints had a fully modern foot shape and were pushing off their big toes and shifting their weight exactly as modern humans do.

Answers in Genesis, of course, was delighted to report on this, claiming that it confirmed their belief that Homo erectus was a modern human (never mind the more primitive features of pelvis, shoulder and skull found in Homo erectus). So did the Institute for Creation Research. But AIG and ICR carefully avoided mentioning information from the paper that did not fit with their agenda.

We have already pointed you to afarensis’s deconstruction of Casey Luskin’s post on Lucy at the Discovery Institute Media/Museum Complaints Division. Luskin attempted to argue, based on his detailed study of a museum exhibit and some quote-mining, that the entire world community of paleoanthropologists has no idea what they are talking about when it comes to Lucy. Afarensis was calm and polite, which was fine and admirable, but the one danger of being completely polite when commenting on something like Luskin’s piece is that the degree of outrageousness, incompetence, and silliness in the creationists’ work is not fully exposed. For example, it’s not just wrong to say, as Luskin does, that Lucy is the most complete hominid skeleton available, it’s wildly, flabbergastingly, bang-your-head-against-the-wall obvious that this is wrong, and anyone even vaguely familiar with the field knows it. Anyone who didn’t know it could look it up in 10 seconds on google and find for example the Homo erectus specimen Turkana Boy.

Today’s most heavily blogged science story is probably the discovery of a new species of early whale. A team of researchers led by whale evolution expert Philip Gingerich discovered the remains - a largely complete adult male, and a female that was carrying a near-term fetus - during field work in Pakistan in 2000 and 2004. They’ve named the new species Maiacetus inuus.

If you’re interested in learning more about this fascinating discovery and what it can tell us about the evolution of whales, here are a few links to check out:

The PLoS one paper that describes the species

Bora’s collection of blog links
The article about the new find at Laelaps - if you don’t read any others, read that one.

Recently, I blogged about the newly discovered skeletal bones of the Dmanisi hominids (Lordkipanidze et al. 2007, Gibbons 2007, Lieberman 2007), and the Discovery Institute’s response to them. (In a nutshell, Casey Luskin of the DI attempted to argue that the Dmanisi hominids were apes, an argument that is untenable for any number of reasons).

I know of only one other creationist discussion of the Dmanisi skeletons, in an article by Answers in Genesis (AIG) (scroll down to the 2^nd item). It is fascinating to observe that AIG has decided that the Dmanisi hominids are humans, in contrast to Luskin’s opinion that they were probably apes. If either side is right, the other must be hopelessly incompetent (not excluding, of course, the possibility that both are incompetent).

It’s worth noting that AIG also disagrees with their own “expert” on human evolution, Marvin Lubenow. Lubenow is the author of Bones of Contention (2^nd edition, 2004), the leading creationist book on human evolution. It is enthusiastically praised by creationists, and sold and recommended by AIG, who call it “the leading creationist work in fossil study today”. Lubenow’s book doesn’t have any discussion of the Dmanisi skulls (the skeletal bones were not then known), but he does put the largest of the 3 Dmanisi skulls in his list of H. erectus fossils (which he considers human, p.350), and the smaller 2 Dmanisi skulls in his list of H. habilis fossils (p.352), which he considers to be apes.

So I have a question for Answers in Genesis. Why do they say that the smaller Dmanisi skulls belong to H. erectus and are human, if the man they recognize as the creationist expert on human evolution thinks they are apes?

In justifying their diagnosis, AIG quotes one of their other articles on human evolution, which claims:

The site of Dmanisi in the Republic of Georgia has produced four superb hominid skulls ranging in size from 600 cm³ to 780 cm³. These sizes range from the lower end of Homo erectus downwards into the Homo habilis range. The fossils contain a mixture of anatomical features from erectus and habilis. They could arguably be considered to belong either to primitive H. erectus (or H. ergaster), or to a new species, Homo georgicus. Vekua et al 2002 concluded:

The Dmanisi hominids are among the most primitive individuals so far attributed to H. erectus or to any species that is indisputably Homo, and it can be argued that this population is closely related to Homo habilis (sensu stricto) as known from Olduvai Gorge in Tanzania, Koobi Fora in northern Kenya, and possibly Hadar in Ethiopia.

These skulls are intermediate in both anatomy and size between Homo erectus and H. habilis, and as a result are exceedingly difficult for creationists to classify. Creationists therefore either ignored them (the usual reaction), or were forced into the absurdity of claiming that the biggest skull is human but the smallest two are apes (Lubenow 2004), or the almost equally implausible suggestion that all of them are human (Line 2005).

In 2007, further light was thrown on the Dmanisi hominids with the announcement that a substantial number of bones from below the skull had been discovered (Lordkipanidze et al 2007). These included a right femur, tibia and kneecap (the most complete known lower limb of early Homo); an ankle bone, part of a shoulder blade, three collar bones, three upper arm bones, five vertebrae, and a few other small bones. Some of these bones were associated with some of the previously discovered skulls.

Analysis of the bones shows that the Dmanisi hominids definitely walked bipedally and upright. However, the bones show a number of differences from modern humans and have some features associated with Homo habilis. The upper body differences lead the authors to suggest, with some caution, that “the Dmanisi hominins would have had a more australopith-like than human-like upper limb morphology”.

Their final conclusion was:

The New York Times’s science pages discuss a research study of Tiktaalik. The study in question has been published in the Journal Nature (1)

It was Neil Shubin’s team that found the Tiktaalik, as they had predicted.

Dr. Shubin said Tiktaalik was “still on the fish end of things, but it neatly fills a morphological gap and helps to resolve the relative timing of this complex transition.”

For example, fish have no neck but “we see a mobile neck developing for the first time in Tiktaalik,” Dr. Shubin said.

Anne Minard of National Geographic News writes on July 9^th

The discovery of a missing link in the evolution of bizarre flatfishes—each of which has both eyes on the same side of its head—could give intelligent design advocates a sinking feeling.

CT scans of 50-million-year-old fossils have revealed an intermediate species between primitive flatfishes (with eyes on both sides of their heads) and the modern, lopsided versions, which include sole, flounder, and halibut.

So the change happened gradually, in a way consistent with evolution via natural selection—not suddenly, as researchers once had little choice but to believe, the authors of the new study say. … Though known for their odd eye arrangement, no flatfish start life that way. Each is born symmetrical, with one eye on each side of its skull.

As a flatfish develops from a larva to a juvenile, one eye migrates up and over the top of the head, coming to rest in its adult position on the opposite side of the skull. … Palmer added that the new work is “a fantastic paper” that helps resolve a mystery “that’s bedeviled evolutionary biologists for more than a century.

“It’s really been a major, major puzzle to evolutionary biologists.”

As expected, the Magisterium of Intelligent Design was quick to condemn the finding as simply floundering around, while the Institute of Creation Research has a turbot-charged attack on the finding, pointing out that flatfish are sole-ly members of the flatfish ‘kind,’ and putting National Geographic in it’s plaice.

Neil Shubin’s latest book on evolutionary theory is by all standards a great success. It ranks around 200 in Amazon books and first in Evolution Science Books. When I checked the book’s availability in our library system there were close to 40 pending holds.

A sales rank of 200 means 225-250 books per week are sold. Compare this to a rank of 24,000 for Behe’s boo “Edge of Evolution” sold at a bargain price of $6.99 down from $28.00 or 111,550 for the regular priced version. Those numbers translate to few copies per month being sold.

Neil Shubin is a professor of organismal biology at the University of Chicago. He, as part of a team of scientists, discovered the now infamous Titaalik transitional fossil which causes so much consternation amongst Intelligent Design Creationists. His book Your Inner Fish introduces its readers to an exciting overview of how our evolutionary history links us back to a common ancestor with fish. Of course, that’s not where our common ancestry ends.

Why do we look the way we do? What does the human hand have in common with the wing of a fly? Are breasts, sweat glands, and scales connected in some way? To better understand the inner workings of our bodies and to trace the origins of many of today’s most common diseases, we have to turn to unexpected sources: worms, flies, and even fish.

In Your Inner Fish, Neil Shubin tells the story of evolution by tracing the organs of the human body back millions of years, long before the first creatures walked the earth. By examining fossils and DNA, Shubin shows us that our hands actually resemble fish fins, our head is organized like that of a long-extinct jawless fish, and major parts of our genome look and function like those of worms and bacteria.

Although many have read the transcripts of the Kitzmiller v. Dover trial (HTML version | PDF version) and found them interesting, reading the transcripts does not give the full sense of what it was like to be in the Kitzmiller courtroom. In real life, in addition to the witness answering questions, the lawyers and witnesses were constantly referring to exhibits that were digitally projected onto a large screen on the right wall of the courtroom. Usually the exhibits were just documents, but when the science witnesses testified, their powerpoint presentations contain fossils, flagella, and everything else in between. I think it is safe to say that the testimony is much easier to understand when read with the demonstrative exhibits available (the exhibit lists and a few exhibits are available online).

However, it takes a lot of work to convert the slides to web format, add captions, embed them in HTML, etc. But as a first step, I and others at NCSE have done this for Kevin Padian’s testimony (testimony+slides | just slides).

I missed this one a week or two ago. Simon Conway Morris and his colleague Jean-Bernard Caron published a paper in Science on a new Cambrian fossil called Orthrozanclus. The cool thing about the fossil is that it combines features from two other fossils that Conway Morris previously implicated as transitional stem groups between the modern crown groups (“phyla”) of mollusks, annelids, and brachiopods: Wiwaxia and Halkeria. Of course, according to Discovery Institute propaganda, transitional fossils like this don’t exist.

Here is a news summary. See also the Orthrozanclus post from PZ Myers, his post last year on another stem group mollusk-ish critter, Odontogriphus.