Little Foot Finally Extricated

Nature News is reporting on the excavation and description of "Little Foot," a fossil initially discovered twenty years ago by Ron Clarke, at Sterkfontein Cave, in South Africa.  Colin Barras writes:

After a tortuous 20-year-long excavation, a mysterious ancient skeleton is starting to give up its secrets about human evolution.

The first of a raft of papers about ‘Little Foot’ suggests that the fossil is a female who showed some of the earliest signs of human-like bipedal walking around 3.67 million years ago. She may also belong to a distinct species that most researchers haven’t previously recognized.

“It’s almost a miracle it’s come out intact,” says Robin Crompton, a musculoskeletal biologist at the University of Liverpool, UK, who has collaborated with the research team that excavated the skeleton.

Why has this task taken so long and why is it so important? Barras continues:

By late last year, Clarke’s team had successfully removed enough bones to reconstruct more than 90% of the skeleton, and the specimen was unveiled to the world. No other Australopithecus fossil comes close to that level of completeness. For comparison, the most famous Australopithecus — Lucy — is around 40% complete.

Clarke and colleagues have posted a number of papers on the BiorXiv biology pre-print server. One of the papers is titled "The skull of StW 573, a 3.67 Ma Australopithecus skeleton from Sterkfontein Caves, South Africa."  Because these papers are unpublished, they are open-access. 

As Clarke and Kuman notes, this fossil is unlike those of Australopithecus africanus, a species ubiquitous in South Africa but more closely resembles, in some ways, Au. afarensis (Lucy) and Au. anamensis, both of which are north east African variants of Australopithecus and are the earliest members of that genus.  The fossil has been included, taxonomically, with a species originally described by Raymond Dart in 1948: Australopithecus prometheus.  Given its early date, the researchers argue that it cannot be descended from Au afarensis but must be coeval with it.  This suggests that both are descendants of an earlier species that had a large home range. 

More pieces to the puzzle. 

Ardipithecus May Not Have Been Entirely a Facultative Biped After All

In a new article in the Proceedings of the National Academy of Sciences, several researchers have concluded, using 3D morphometric analysis have discovered that Ardipithecus ramidus, while still having facultative (didn't have to but could) bipedalism, when it did walk, its bipedal gait was nearly human.  From the abstract:

We show that hamstring-powered hip extension during habitual walking and climbing in living apes and humans is strongly predicted, and likely constrained, by the relative length and orientation of the ischium. Ape pelves permit greater extensor moments at the hip, enhancing climbing capability, but limit their range of hip extension, resulting in a crouched gait. Human pelves reduce hip extensor moments but permit a greater degree of hip extension, which greatly improves walking economy (i.e., distance traveled/energy consumed). Applying these results to fossil pelves suggests that early hominins differed from both humans and extant apes in having an economical walking gait without sacrificing climbing capability. Ardipithecus was capable of nearly human-like hip extension during bipedal walking, but retained the capacity for powerful, ape-like hip extension during vertical climbing. Hip extension capability was essentially human-like in Australopithecus afarensis and Australopithecus africanus, suggesting an economical walking gait but reduced mechanical advantage for powered hip extension during climbing.

This positions Ardipithecus as the classic intermediate in terms of bipedal locomotion.Although there are many traits in Australopithecus afarensis that are still transitional in terms of the rib cage, dentition and aspects of the hip, it is clear that the major adaptations for bipedalism were in place nearly a million years earlier.  This also suggests that it is not out of the realm of possibility that the fossil footprints in Crete really do reflect a bipedal hominin.  At the risk of positing heresy, the fact remains that we really don't know exactly where hominins first appeared.  This study also reinforced the distinct separation between apes and humans in terms of iliac shape, and that this split must have taken place even further back in time that we have supposed.

The Independent has a news story on this here.  One of the authors, Herman Pontzer remarks:

“It kicks us out of this old paradigm of thinking about human evolution,”...“In that old picture that is everywhere where you have the evolution of man going from crouching thing to upright thing to a human – as much as we have known that is not right, I still think people have it in their heads.”

3.3 Million Year Old Vertebral Column Confirms Human Pattern of Au. afarensis

The science site PhysOrg has posted a story on a study of the 3.3 million year old fossil from the site of Dikika, in the Afar Triangle.  The fossil, known as Selam, is an almost complete skeleton of a 2 ½ year-old child. From the story:

Many features of the human spinal column and rib cage are shared among primates. But the human spine also reflects our distinctive mode of walking upright on two feet. For instance, humans have fewer rib-bearing vertebrae - bones of the back - than those of our closest primate relatives. Humans also have more vertebrae in the lower back, which allows us to walk effectively. When and how this pattern evolved has been unknown until now because complete sets of vertebrae are rarely preserved in the fossil record.

"For many years we have known of fragmentary remains of early fossil species that suggest that the shift from rib-bearing, or thoracic, vertebrae to lumbar, or lower back, vertebrae was positioned higher in the spinal column than in living humans. But we have not been able to determine how many vertebrae our early ancestors had," said Carol Ward, a Curator's Distinguished Professor of Pathology and Anatomical Sciences in the University of Missouri School of Medicine, and lead author on the study. "Selam has provided us the first glimpse into how our early ancestors' spines were organized."

This gives us much better evidence of how bipedality was practiced in some of the earliest hominins. We know, from the footprints at Laetoli and the hip remains of Lucy, that Au. afarensis was bipedal but now we know that the rib structure had evolved into a more human pattern. 

New Hominin Species Coeval with Au. afarensis

A new hominin has been announced by Haile-Selassie and colleagues.  Here is the abstract from the Nature paper¹:

Middle Pliocene hominin species diversity has been a subject of debate over the past two decades, particularly after the naming of Australopithecus bahrelghazali and Kenyanthropus platyops in addition to the well-known species Australopithecus afarensis. Further analyses continue to support the proposal that several hominin species co-existed during this time period. Here we recognize a new hominin species (Australopithecus deyiremeda sp. nov.) from 3.3–3.5-million-year-old deposits in the Woranso–Mille study area, central Afar, Ethiopia. The new species from Woranso–Mille shows that there were at least two contemporaneous hominin species living in the Afar region of Ethiopia between 3.3 and 3.5million years ago, and further confirms early hominin taxonomic diversity in eastern Africa during the Middle Pliocene epoch. The morphology of Au. deyiremeda also reinforces concerns related to dentognathic (that is, jaws and teeth) homoplasy in Plio–Pleistocene hominins, and shows that some dentognathic features traditionally associated with Paranthropus and Homo appeared in the fossil record earlier than previously thought.

The Washington Post has a write-up of the new find, which they glibly refer to as “An Ethel for Lucy.” Rachel Feltman:

Haile-Selassie and his co-authors believe the find should encourage reexamination of other possible instances of pre-Homo cohabitation.  Two other species have been proposed as living at the same time as Australopithecus afarensis -- Australopithecus bahrelghazali and Kenyanthropus platyops -- but both remain controversial, with some scientists saying they aren't different enough from A. afarensis to constitute a new species. And in a previous expedition, Haile-Selassie himself found a partial foot that he believed was from the same time period -- but not the same species -- as Lucy. Unlike the jaw reported in Nature, the foot didn't provide enough evidence to name a new species.

As noted with the Ledi jaw, there seems to be quite of a bit of morphological variability and experimentation going on at the Plio-Pleistocene boundary.   

¹Haile-Selassie, Y., Gibert, L., Melillo, S.M., Ryan, T.M., Alene, M., Deino, A., Levin, N.E., Scott, G., Saylor, B.Z. (2015) New species from Ethiopia further expands Middle Pliocene hominin diversity. Nature. 521(7553): 483-488.
http://dx.doi.org/10.1038/nature14448

Earliest Stone Tools?

Artifacts have been found near Lake Turkana that are reported to be the earliest stone tools yet produced.  Live Science has this:

Until now, the earliest known tools were about 2.8 million years old, the researchers said. The artifacts are by far the oldest handmade stone tools yet discovered — the previous record-holders, known as Oldowan stone tools, were about 2.6 million years old.

"We were not surprised to find stone tools older than 2.6 million years, because paleoanthropologists have been saying for the last decade that they should be out there somewhere," Harmand said. "But we were surprised that the tools we found are so much older than the Oldowan, at 3.3 million years old."

It remains unknown what species made these stone tools. They could have been created by an as-yet-unknown extinct human species, or by Australopithecus, which is currently the leading contender for the ancestor of the human lineage, or by Kenyanthropus, a 3.3-million-year-old skull of which was discovered in 1999 about a half-mile (1 kilometer) from the newfound tools. It remains uncertain exactly how Kenyanthropus relates to either Homo or Australopithecus.

Part of this is because Kenyanthropus is very badly deformed postmortem and it is very hard to figure out its morphology. In recent years, it has not been seriously included in human lineage models.There is evidence at the site of Gona for the use of tools, around 3.3 million years ago, but no actual tools, themselves.  This represents a more concrete example of early tools.  According to the picture, these are very rudimentary choppers.  More pieces of the puzzle.

Elizabeth Mitchell, David Menton and Andrew Snelling Take on the Ledi Jaw

As noted, the promised report from Answers in Genesis about the Ledi jaw (LD 350-1) is out.  Let's see what they say.  This is an interesting group of authors.  Andrew Snelling is the resident geologist, while David Menton is a former anatomist who wrote a truly terrible article on the evidence for human evolution, which I tackled over six long, straggly posts, ending here.  In it he, effectively, revealed that he has little to no knowledge of the fossil record.  I have read little of Elizabeth Mitchell's posts, other than the one in which she championed the evidence for unicorns in the Bible. 

The opening salvo in the “Lucy Connection” contains this:

An extinct knuckle-walking ape, “Lucy” is generally depicted strolling about East Africa 3 million years ago on her two supposedly arched feet with tiny teeth smiling from her gorilla-like face and tiny brain. That image has created an imaginary place for Australopithecus afarensis in the human lineage.

The initial problem with this paragraph is that there is no evidence to back up their depiction of Au. afarensis. The fossil remains that make up Au. afarensis, of which Lucy is a member, clearly indicate a hominin that was bipedal; that much is not debatable.  It carries none of the traits of an ape in this regard.  However, Au. afarensis does have some ape-like characteristics as well.  In fact, there are quite a list of traits that are Hominin and some that are ape-like.  I chronicled those here, in the fourth part of my response to Menton's 2010 article on human origins.  (Aside: It doesn't bother me that Menton didn't read my post, although Ken Ham knows I write for BioLogos because he referenced one of my posts for them.  It does bother me that Menton persistently mischaracterizes the transitional evidence in Au. afarensis, which is pretty hard to miss, if you are paying any attentional, whatsoever.)

Now, on to the jaw, itself, for which they get the account correct (Here is my short post for BioLogos on the jaw).  In fact, they report pretty much exactly what the discoverers and Fred Spoor determined about the jaw and the reconstruction of the related OH 7 skull. 

The the wheels fall off.

They write:

Could the Ledi jaw’s owner have been a transitional form? No. Evolutionists strain to see something ape-like in the array of Homo traits in the Ledi jaw because its position in the fossil record is so “far back” they think it must be their much sought-after transitional form. Since it lacks a protruding chin no one would suggest this fossil belonged to a modern human, but the lack thereof does not demonstrate that it is Australopithecus afarensis or an ape descended from it or even a less-evolved part of the human lineage. The relatively chinless jaw is simply not typical of modern humans. Nothing about this fossil indicates that its owner still had one foot in the ape-camp and was only in the process of evolving into a full-fledged human.

They are correct that the lack of a chin keeps it out of the modern human camp.  They are incorrect that it doesn't have transitional characteristics. Here is the relevant quote from the article¹:

Indeed, in overall dental and mandibular size LD 350-1 matches smaller specimens of A. afarensis (figs. S1 to S4 and tables S1 to S3). In addition, LD 350-1 shares with A. afarensis a primitive anterior corpus, including an inclined symphyseal cross section, a bulbous anterior symphyseal face, and a projecting inferior transverse torus that is only slightly elevated above the corpus base (Fig. 2A).

What then follows in the scholarly article is a long discussion of no fewer than five distinct characteristics that align the Ledi jaw with Homo to the exclusion of Au. afarensis.  Villmoare and colleagues are keenly aware of the differences between australopithecine and human morphology.  This is why they can recognize these traits.  Thus, when Mitchell, Menton and Snelling write that nothing about the Ledi Jaw is transitional, and provide no evidence of their position, one is tempted to not take them seriously.  The next paragraph is no better:

The Ledi jaw’s bid to be Homo or an early transition to Homo rests largely on the fact that its assigned dates place it in the desired gap between the ape Lucy and archaic varieties of humans. Had its host sediment been dated substantially older, its human features would likely have been ignored or explained away. Evolutionists have been known to dismiss fossil evidence of very early Homo, no matter how similar to modern man, if the stratigraphically assigned dates are too old to fit into the evolutionary schema.

This is illogical. Why would evolutionists care how old it is? There are some, in fact, who would relish the idea of our line being pushed back even further.  The human features are there, regardless of how old it is.  That is why it is making waves—because it has the human features.  If it had been found to be older, the human-like features would not have vanished like the snows of yesteryear.  They would still have been there. 

The last sentence in the quote is, once again, presented without evidence and calls into question the integrity of the scientists involved in this discovery and others like it.  What evidence has been dismissed?  How has it been explained away? To call into question the motives of scientists and call them duplicitous without giving evidence to that effect is worthy of scorn and disrespect.  Put up or shut up.

Next.

The Ledi jaw wouldn’t even be close to being the oldest “Homo” if certain other fossil bones and footprints that are virtually identical to modern man were rightly recognized as Homo sapiens. For example, the Laetoli footprints are claimed to be 3.66 million years old and are virtually identical to modern man’s footprints, but no evolutionist considers them to be human because they are simply too old. The Kanapoi elbow fossil from the Lake Rudolf region of northern Kenya is the distal end of a humerus that is indistinguishable from Homo sapiens, but it is considered to be australopithecine in origin because it is also too old at 4.0–4.5 million years to be considered human. These assigned dates, based on a host of worldview-based unverifiable assumptions, blind evolutionists to the true identity of fossils like these. In truth, humans have been around since the sixth day of the Creation Week, the first two people having been created by God the same day as the land animals.

They are right, the footprints are too old, given that there is no evidence for modern humans until around 190 thousand years ago. The footprints are securely dated by radiometric techniques that the folks from AiG will never accept, despite their robusticity.  Same with the Kanopoi remains.  What this simply means is that, as with many transitional forms at this time, some characteristics were more human-like than others.  What these authors do not mention is that in other fossils from the time period, there are ape-like characteristics as well.  The elbow traits, along with the knee and hip traits are derived in the direction of Homo.  The simian traits are retained from their ancestors.

What these authors do fail to demonstrate is that there are fully modern humans in the same strata as the australopithecines.  That would sink our understanding of human origins once and for all.  Yet, that has never been done. 

They write that this fossil is dated using methods found to have “unverifiable assumptions.”  Curiously, this links to another AiG page on radiometric dating, which, in turn, links to an article authored by Steve Austin, of the ICR, on radiometric dating of Mount St. Helens, rather than actual peer-reviewed scientific articles.

Austin collected dacite samples from around the new St. Helens lava dome, which he knew had been formed around 1986.  He then separated them and sent them to a laboratory for potassium/argon dating.  When the results came back, he declared that radiometric dating was flawed because the results inticated that the dome had been formed around 350 000 years B.P.

In Kevin Henke's response to this report, he addresses how Austin misused the methodology to arrive at his conclusions.  He writes:

Considering that the half-life of potassium-40 (40K) is fairly long (1,250 million years, McDougall and Harrison, 1999, p. 9), the K-Ar method cannot be used to date samples that are much younger than 6,000 years old (Dalrymple, 1991, p. 93). A few thousand years are not enough time for 40Ar to accumulate in a sample at high enough concentrations to be detected and quantified. Furthermore, many geochronology laboratories do not have the expensive state-of-the-art equipment to accurately measure argon in samples that are only a few million years old. Specifically, the laboratory personnel that performed the K-Ar dating for Austin et al. Specifically, personnel at Geochron Laboratories of Cambridge, Massachusetts, USA, performed the K-Ar dating for Austin et al. This laboratory no longer performs K-Ar dating. However, when they did, their website clearly stated in a footnote that their equipment could not accurately date rocks that are younger than about 2 million years old ("We cannot analyze samples expected to be younger than 2 M.Y."; also see discussions by Bartelt et al.). With less advanced equipment, 'memory effects' can be a problem with very young samples (Dalrymple, 1969, p. 48). That is, very tiny amounts of argon contaminants from previous analyses may remain within the equipment, which precludes accurate dates for very young samples. For older samples, which contain more 40Ar, the contamination is diluted and has insignificant effects. Considering the statements at the Geochron website and the lowest age limitations of the K-Ar method, why did Austin submit a recently erupted dacite to this laboratory and expect a reliable answer??? Contrary to Swenson's uninformed claim that ' Dr Austin carefully designed the research to counter all possible objections', Austin clearly demonstrated his inexperience in geochronology when he wasted a lot of money using the K-Ar method on the wrong type of samples.

lawilson200 of Mount St. Helens watch also notes these problems, as does Skeptoid.  If Austin sent the samples to the lab that he knew were produced in 1986, then he either did not know that K/Ar dating requires samples that are at least two million years old to date accurately, or he did know that and submitted them to intentionally get spurious results to publicize the perceived limitations of radiometric dating.  In any event, without the support of Austin's argument, the bad date argument for the Ledi jaw collapses. 

Mitchell, Menton and Snelling write that the geologists studying the area around where the Ledi jaw was found cannot be sure how many stratigraphic layers are missing between the Gurumaha tuff beds and the Lee Adoyta tuff beds, so we cannot know for sure what the total thickness was.  Yes, but we know where the jaw was found and the authors are clear about what the maximum and minimum ages for the fossil can be, based on the dates.  The AiG writers then make an argument that the tuffs could have been formed in hours because of the nature of volcanic eruptions.  This fails to account for the depositional environment between the tuffs, to wit:

Ecological community structure analysis based on mammalian fauna recovered from the Gurumaha fault block indicates a more open habitat (mostly mixed grass-lands/shrublands with gallery forest) that likely experienced less rainfall than any of those reconstructed for the Members of the Hadar Formation (6). The landscape was similar to modern African open habitats, such as the Serengeti Plains, Kalahari, and other African open grasslands, given the abundance of grazing species and lack of arboreal taxa, although the presence of Deinotherium bozasi and tragelphins likely indicate a gallery forest (fig. S6). The existence of Kobus sigmoidalis, aff. Hippopotamus afarensis, crocodiles, and fish in this package reflect the presence of rivers and/or lakes. Approximately one-third of the mammalian taxa present are shared with the youngest Hadar Formation (~3 Ma), while one-third are first appearances of these taxa in the LAV (Table 1). The remaining one-third of mammals recovered can only be identified to the genus level.

How would these landscapes have formed in hours? They reflect hundreds, if not thousands of years of development, and they certainly could not have formed in the middle of a world-wide flood.

The argument presented by AiG also points to a peculiarity of the young earth argument: arguing against a proposition using uniformitarian principles, while at the same time taking no stock in those principles, whatsoever, since they have to be thrown out the window in any flood model. 

They continue:

The evolutionary determination to subdivide varieties of humans into various species is based on evolutionary claims, when in reality all humans would best be called Homo sapiens regardless of their variations. Nevertheless, we are stuck with the terminology that calls the descendants of various people descended like us from Adam and from Noah via the dispersion from Babel by names that imply they are unrelated. Truly, however, when it comes to a fossil like this one, the real question should not be “where in the evolutionary history of humans does it fit?” but rather “does it fit within the norms for human beings or not?” Though limited by its incompleteness, analysis of LD 350-1 suggests it belonged to a person.

Once again, how, then, do you explain the traits that link it to Au. afarensis? Those are clearly non-human. To sweep them under the rug is simply not tenable. These traits are outside the known variation of all modern humans.  No one has them.  Further, they don't even track with traits seen in later hominin forms such as Homo ergaster, Homo erectus or archaic Homo sapiens.  They are clearly australopithecine.

In summary, then, this article written by Mitchell, Menton and Snelling suffers from three principle problems:

1. A failure to correctly describe the fossil material related to the Ledi jaw (Describing Au. afarensis as “An extinct knuckle-walking ape,” for example)
2. A failure to correctly assess the human and non-human morphology of the Ledi jaw, itself, instead simply denying that the non-human traits exist, when in fact, they clearly link it to the preceding australopithecine fossil remains in many ways.
3. Reliance on a single article for rejection of modern radiometric dating assumptions that has been heavily criticized for its misuse of proper methodology. (See this Davis Young article on radiometric dating for a good primer on how reliable it is).

These problems completely sink the AiG's analysis and conclusions of the Ledi jaw.  


¹Villmoare, B., Kimbel, W. H., Seyoum, C., Campisano, C. J., DiMaggio, E., Rowan, J., Braun, D. R., Arrowsmith, J. R., & Reed, K. E. (2015). Early Homo at 2.8 Ma from Ledi-Geraru, Afar, Ethiopia. Science. doi: 10.1126/science.aaa1343

BioLogos, Ken Ham and David Menton—A Response, Part VI: The Conclusion

This concludes my response to David Menton's post on human origins, which has been a chore to read and respond to. Menton's conclusion is so short, I will post it in its entirety:

Why then are there continued efforts to make apes out of man and man out of apes? In one of the most remarkably frank and candid assessments of the whole subject and the methodology of paleoanthropology, Dr. David Pilbeam (a distinguished professor of anthropology) suggested the following:

Perhaps generations of students of human evolution, including myself, have been flailing about in the dark; that our data base is too sparse, too slippery, for it to be able to mold our theories. Rather the theories are more statements about us and ideology than about the past. Paleoanthropology reveals more about how humans view themselves than it does about how humans came about. But that is heresy.

Oh, that these heretical words were printed as a warning on every textbook, magazine, newspaper article, and statue that presumes to deal with the bestial origin of man!
No, we are not descended from apes. Rather, God created man as the crown of His creation on Day 6. We are a special creation of God, made in His image, to bring Him glory. What a revolution this truth would make if our evolutionized culture truly understood it!

First, David Pilbeam wrote that almost forty years ago, and yet Menton appears to hold it up as current scholarship.  You wouldn't do that in any legitimate scientific discipline.  It may be a good example of “look what we thought back then,” in a historical sense and as compare and contrast but not current thought.  This is a typical young earth creationist tactic: find a useful quote and keep using it, long after it is no longer true or has been debunked.  As such, it is no different than using (or abusing) Solly Zuckerman's quote from the early 1970s.  I saw Duane Gish at the University of Tennessee a few years back he used Zuckerman's quote as well.  Once a quote is found, it makes the rounds.

Pilbeam's quote comes from a review of Richard Leakey's book Origins and is found in the American Scientist (Vol. 66, No. 3, May-June 1978).  Let's see what Pilbeam thinks about palaeoanthropology as of 1995:

The discovery of an australopithecine mandible together with a middle Pliocene fauna 2,500 km west of the Rift Valley considerably extends the known range of these early hominids and raises several interesting issues. The Chad specimen is most similar to its East African contemporary A. afarensis. Nevertheless, in certain features-mandibular morphology, premolar roots and enamel thickness- it differs from the described hypodigm of A. afarensis . Given the genetic and morphological differences now recognized between allopatric populations within, for example, Pan troglodytes, Gorilla gorilla, Pongo pygmaeus and Papio hamadryas as well as other African mammals, it is not surprising that contemporaneous hominid populations as geographically distant as Chad and Ethiopia, Kenya and Tanzania would differ in morphology, regardless of whether they are classified as species or subspecies. Here we do not choose to name a new species, recognizing that more detailed comparisons are necessary before the taxonomy of this Bahr el Ghazal hominid can be resolved.¹

Here, he and the other authors of the paper clearly feel that the state of the discipline is sound enough to make educated pronouncements about the fossil record.  In all of Pilbeam's papers, it is clear that he is committed “evolutionist.” As with all palaeoanthropologists, he accepts that there may be aspects of the study that are not known or poorly understood but, of the central tenet: that humans have evolved, there is clearly no doubt.  Thirty six years is a long time in the history of a scientific discipline.

How good is our understanding of the human fossil record now?  Here is what another distinguished professor of anthropology, Richard Klein, has to say:

In the absence of fossils, Darwin could not have predicted the fundamental pattern of human evolution, but his evolutionary theory readily accommodates the pattern we now recognize. Probably the most fundamental finding is that the australopithecines, who existed from at least 4.5 million to 2 million years ago, were distinguished from apes primarily by anatomical specializations for habitual bipedalism, and it was only after 2 million years ago that people began to acquire the other traits, including our unusually large brains, that readily distinguish us from the living apes. The greatly expanded fossil record shows that the australopithecines comprised multiple species, and it suggests that our own genus, Homo, descended from one of these about 2.5 million years ago.²

Note the phrase “the greatly expanded fossil record.” Recall the two compendia on this fossil record I mentioned in the first part of this response. Menton clearly is unfamiliar with this record and his attempts to discredit it are shallow, as a result.

To recap:

• He claims that “evolutionists” just accept similarities between fossil bones of living men and fossilized apes as evidence of ancestry. Such a statement betrays a lack of understanding of homology, functional morphology and the modern study of evolutionary systematics. It glosses over important skeletal structures that arose during our ancestry and which separate our direct ancestors from all apes, fossil or otherwise.
• He massively under-emphasizes the size of the human fossil record and the complexity of it, simply dismissing it with no examination or explanation.
• He suggests that research projects cannot be undertaken based on pictures and measurements of fossil hominins.  This is absurd.  There is no scientific discipline that does not rely on published reports.  Moreover, this is a peculiar statement coming from a professor of anatomy, who must have, during his tenure as a professor, read countless articles on aspects of anatomy in which there were published measurements and pictures.  What was he to make of those?  Did they not constitute real research on which he based his own?
• He mistakenly calls a spider monkey an ape, bringing into question his understanding of basic primate taxonomy.  Further, while his anatomical specialty seems to have been at the cellular level, he betrays a peculiar lack of understanding of human morphological functional interrelatedness by suggesting that the carrying angle of hominins can be dissociated from hip, limb and cranial morphology.  While it may be true that some apes have a similar carrying angle to humans, not a one of them has a foramen magnum at the base of the skull, angled femoral condyles, or a flat, wide pelvis.  Further, these derived traits show up in the fossil record around 3.7 million years ago.  How did he miss these things?  When I took gross anatomy and physiology, I was required to learn not just developmental biology, but functional and comparative morphology.  Has he forgotten his?
• He writes that Ardipithecus, Orrorin, Sahelanthropus, and Kenyanthropus all have “obviously ape skulls, ape pelvises, and ape hands and feet” despite the fact that only one of these finds preserves the skeletal parts he references. This suggests that he never even bothered to look at the reports detailing these finds.  To make such errant, blanket statements about them is incompetent and sloppy. 
• He cherry-picks quotes that support his position and ignores ones that do not.  While he calls A. afarensis “long-armed knuckle-walkers” and suggests that palaeoanthropologists Stern and Susman³ argue that it is an ape, he carefully ignores other paragraphs from their article, in which they clearly argue that it is transitional between apes and humans, even using the phrase “missing link.”  He then (again, oddly for an anatomist) ignores other critical morphology of A. afarensis that clearly indicates its transitional status.
• He writes that Neandertals were considered human but have recently been denigrated to non-human status, when in fact, that is precisely backwards.  From their initial discoveries, Neandertals were considered subhuman^4,5 and it has only been within the last thirty years that their relationship to modern humans has been reassessed, inviting claims by some that they represent simply an earlier version of us and incorporating new genetic knowledge of interbreeding between Neandertals and modern humans⁶.  

This is a badly written post that shows little in the way of actual research.  He seems to misunderstand basic anatomy, gets fossil descriptions wrong, quote-mines to show only what appears to support his position and seems to show no understanding of basic evolutionary biology.  His demeanor is pompous and contemptuous and his treatment of the subject matter invites scorn.

I have absolutely no doubt that Dr. Menton is a bible-believing Christian and that, as such, he is an asset to the kingdom.  I also believe that, like so many other young-earth creationists I am familiar with, he treats the fossil material and the discipline of evolutionary biology with dishonesty and lack of integrity.  This saddens me since it, as with all of creation, reflects the goodness, glory and, importantly, the awesomeness of God.  Further, it is a bad witness and pushes people away from God. 

¹Brunet, M, Beauvilain, A, Coppens, Y, Heintz, E, Moutaye, A, Pilbeam, D. (2014) The first australopithecine 2,500 kilometres west of the Rift Valley (Chad). Nature 378, November 16, 1995
²Klein, R. G. (2009). Darwin and the recent African origin of modern humans. Proceedings of the National Academy of Sciences, 106(38), 16007-16009.
³Stern Jr, J. T., & Susman, R. L. (1983). The locomotor anatomy of Australopithecus afarensis. American Journal of Physical Anthropology, 60(3), 279-317.
⁴Boule, M. (1913). L'homme fossile de La Chapelle-aux-Saints: Masson.
⁵Virchow, Rudolf. Untersuchung der Neanderthal Schädels. 1872.
⁶For example: Sankararaman S, Patterson N, Li H, Pääbo S, Reich D (2012) The Date of Interbreeding between Neandertals and Modern Humans. PLoS Genet 8(10): e1002947. doi:10.1371/journal.pgen.1002947
⁷Krings, M., Stone, A., Schmitz, R. W., Krainitzki, H., Stoneking, M., & Pääbo, S. (1997). Neandertal DNA sequences and the origin of modern humans. Cell, 90(1), 19-30.

BioLogos, Ken Ham and David Menton—A Response, Part IV

This is the fourth part of my response to David Menton's post on human origins.  Links to the first three appear below this post.  Menton continues his ham-fisted, ignorant attack on the human fossil record.

Point 8.  He writes:  

Many apemen are merely apes that evolutionists have attempted to upscale to fill the gap between apes and men. These include all the australopithecines, as well as a host of other extinct apes such as Ardipithecus, Orrorin, Sahelanthropus, and Kenyanthropus. All have obviously ape skulls, ape pelvises, and ape hands and feet. Nevertheless, australopithecines (especially Australopithecus afarensis) are often portrayed as having hands and feet identical to modern man; a ramrod-straight, upright posture; and a human gait.

The best-known specimen of A. afarensis is the fossil commonly known as “Lucy.” A life-like mannequin of “Lucy” in the Living World exhibit at the St. Louis Zoo shows a hairy, humanlike female body with human hands and feet but with an obviously apelike head. The three-foot-tall Lucy stands erect in a deeply pensive pose with her right forefinger curled under her chin, her eyes gazing off into the distance as if she were contemplating the mind of Newton.

Few visitors are aware that this is a gross misrepresentation of what is known about the fossil ape Australopithecus afarensis. These apes are known to be long-armed knuckle-walkers with locking wrists. Both the hands and feet of this creature are clearly apelike. Paleoanthropologists Jack Stern and Randall Sussman2 have reported that the hands of this species are “surprisingly similar to hands found in the small end of the pygmy chimpanzee–common chimpanzee range.” They report that the feet, like the hands, are “long, curved and heavily muscled” much like those of living tree-dwelling primates. The authors conclude that no living primate has such hands and feet “for any purpose other than to meet the demands of full or part-time arboreal (tree-dwelling) life.” 

Some background involving the Miocene apes. At the beginning of the Miocene epoch, apes had largely generalized skeletal structures, with few of the adaptations that we see in the modern apes, or in humans.  Toward the end of the Miocene, biomechanical adaptations are seen in many of the apes.  For example, Oreopithecus has developed a locomotor pattern seen in modern non-human apes (although it was mis-identified by Casey Luskin as bipedal).

Menton, having taken us through the differences between apes and humans, suggests that Ardipithecus, Orrorin, Sahelanthropus and Kenyanthropus all have “obviously ape skulls, ape pelvises, and ape hands and feet.”

Really?

• Kenyanthropus consists of a single skull find that is so badly crushed that most researchers have pretty much written it off as being unusable in taxonomic reconstruction.
• Sahelanthropus is also a single skull find that was also crushed and may, in fact, be a surface find.
• Orrorin tugenensis is a collection of post-cranial remains, the most important of which is a partial femur, which showed clear adaptations toward bipedality. 
• Ardipithecus ramidus consists of both cranial and post-cranial remains, including both hands and feet.  Here is what Owen Lovejoy and colleagues wrote about it in 2009:

“The gluteal muscles had been repositioned so that Ar. Ramidus could walk without shifting its center of mass from side to side. This is made clear not only by the shape of its ilium, but by the appearance of a special growth site unique to hominids among all primates (the anterior inferior iliac spine). However, its lower pelvis was still almost entirely ape-like, presumably because it still had massive hindlimb muscles for active climbing.”

How does Menton describe the locomotion of modern apes?  He writes:

These animals manage to keep their weight over their feet when walking by swinging their body from side to side in the familiar “ape walk.” 

Yet he calls Ardipithecus “merely” an ape. By his own description, Ardipithecus is clearly not “merely” an ape. Did he just miss this detail, or did he simply choose not to include it?

To recap this point,  he writes that all of the finds he mentions have “obviously ape skulls, ape pelvises, and ape hands and feet,” and yet we find that only one of the finds has those body parts preserved.  He, further, ignores critical morphology on the Ardipithecus remains to make it seem as if it has no hominin adaptations.  How are we to believe what he writes when he so incompetently describes the fossils he is denigrating?

Point 9: In quoting Stern and Susman, here, again, Menton picks and chooses what he wants to use and doesn't tell his audience other critical information that undercuts his position.  Menton writes as if Australopithecus afarensis were only an ape, yet Stern and Susman write, in their conclusion:

In our opinion A. afarensis is very close to what can be called a “missing link.” It possesses a combination of traits entirely appropriate for an animal that had traveled well down the road toward full-time bipedality, but which retained structural features that enabled it to use the trees efficiently for feeding, resting, sleeping, or escape. prior to the discovery of the Hadar remains, one could not have predicted precisely what combination of traits would be found in a transitional form such as A. afarensis.

These writers, who, unlike Menton, examined the remains directly, clearly did not conclude it was merely an ape but, in fact, a transitional form between the apes that came before, and the hominins that came after.

But worse, Menton completely ignores other characteristics of A. afarensis that don't just undercut his position that it is merely an ape, they destroy it. 

• The first premolar in apes (or bicuspid if you prefer) is long and rotated toward the front of the mouth. This is so it can constantly sharpen the maxillary canine as the ape bites down. This is known as a "sectorial premolar". In humans, this tooth is rotated so that the cusp division is parallel to the tooth row and does not stick up beyond it. The maxillary canine is, correspondingly, short. In Australopithecus afarensis, this tooth is rotated HALF-WAY and partially sticks up from the tooth row. The canine is shortened as in modern humans.

• The palate of the mouth in apes is shaped like a hard "U" with the back teeth parallel to each other. In humans, the palate is more "V" shaped. In A. afarensis, it is intermediate between these two shapes.

• In apes, there is a distinct space between the canine and the first premolar, called a diastema. In humans, this space is absent. In A. afarensis, a diastema is present but it is remarkably reduced in size over the ape condition.

In other instances, some characteristics are completely ape-like and some are completely human-like. For example:

• The digits (phalanges) on both the hands and feet are curved, as in apes. In humans, they are straight.

• The pelvis is flared (wide from side to side) and short from top to bottom, as in humans.

• The hole in the skull where the spinal chord exits the brain, the foramen magnum, is located on the bottom of the skull in Australopithecus afarensis, as in humans.  Having a hole at the base reflects a bipedal gait.

• the knee joint, which preserves the bottom (distal) section of the femur and the top (proximal) section of the tibia shows that the femur is angled, as in humans. This is the "carrying angle" of which Menton wrote. The A. afarensis position, once again, reflects bipedalism.

These characteristics are exactly what you would expect to find in a transitional species: some characteristics transitional, some ape-like and some human-like. Most of the above information was taken from Lucy: The Beginnings of Humankind and Johanson et al. (1982) but can be found in most textbooks about this subject.  It is amazing that Menton went to no effort to locate this information before dismissing A. afarensis' transitional status without thought.    It is, further, amazing that Ken Ham would hold Menton's post up as being authoritative when it is so badly researched and written.

On to Part V. 

A New Species of Hominin Coeval With Lucy?

Great Googlymoogly! A new discovery has been made in the Afar triangle that indicates that a similar species of Australopithecus that was not A. afarensis lived alongside them. Science Daily writes:

“The Burtele partial foot clearly shows that at 3.4 million years ago, Lucy’s species, which walked upright on two legs, was not the only hominin species living in this region of Ethiopia,” said lead author and project leader Dr. Yohannes Haile-Selassie, curator of physical anthropology at The Cleveland Museum of Natural History. “Her species co-existed with close relatives who were more adept at climbing trees, like ‘Ardi’s’ species, Ardipithecus ramidus, which lived 4.4 million years ago.”

There is nothing to dictate that there were no intermediates between Ar. ramidus and Au. afarensis or that there were not several hominins on the landscape at this point. We know that there were two species of Ardipithecus. It is possible that this represents a descendent of Ar. ramidus or a descendent of a species that lived at the same time as Ardi and gave rise to a hominin that was more arboreal in nature. Until we have more to go on, it will be hard to construct any relationships that are even provisional.

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Next BioLogos Post is Up

Part two of the Dispersal of the Australopithecines is up over at BioLogos. This covers the south African forms as well as the extinction/disappearance of the australopithecines as a whole. Comments welcome.

New BioLogos Post: The Human Fossil Record, Part 4: Australopithecus Conquers the Landscape

My newest post for BioLogos is up: The Human Fossil Record, Part 4: Australopithecus Conquers the Landscape. It focuses on the appearance of early Australopithecus and the shift to full-time bipedality.

More Evidence For A Gradual Shift to Bipedalism

Discovery News has a story on work that is being done on early hominid locomotion. Jennifer Viegas writes:

Early human ancestors stopped swinging in trees and started walking on the ground sometime between 4.2 and 3.5 million years ago, according to a new study.

This key moment, when our ancestors became anatomically and behaviorally less ape-like, coincides with increased cooling, more defined seasonality, and a grassland growth spurt. All transformed former forest habitats into more varied ones, forcing our very early relatives to change their ways.

"With the trees being farther apart, it became energetically advantageous for hominids to cross the gaps bipedally," said Gabriele Macho, lead author of the study that was published in the latest issue of Folia Primatologica.

This follows on the heels (sorry) of the recent studies on Ardipithecus, where it was found that this hominid had a skeletal pattern that was adapted not just for the trees but for bipedal walking as well. How long was this pattern maintained? Viegas continues:

The scientists observed that the Australopithecus anamensis wrist bones exhibited pressure loads associated with modern arboreal animals. The analyzed Australopithecus afarensis bones conversely showed stress loads comparable to those of more terrestrial species, including modern humans.

The researchers concluded that the important shift in early hominid lifestyle happened around the time when A. afarensis first emerged.

A. anamensis is the form that followed, at least chronologically, Ardipithecus ramidus. Whether or not there is a direct ancestor/descendant relationship there, it is clear that the transitional elements in Ardipithecus were continued in the hominid line and that A. anamensis maintained a similar adaptation to the environment. The true changes in bipedalism and adaptation came with A. afarensis. This is yet another piece of the puzzle at this critical point in our history.

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Laetoli Footprints To Be Visible Again

AllAfrica.com is reporting that the Laetoli footprint tracks, produced by two side-by-side hominids some 3.6 million years ago, will be visible again and open for tourists. The author writes:

The state's announcement to open the site may see the beginning of the end for stirring debate over how to best protect the 3.6-millionyear- old tracks. In recent years, experts have been expressing fear for oldest human footprints fossilized tracks preservation, saying weathering has begun to undermine those protections, raising concerns that the prints preserved in a volcanic ash bed could be harmed by erosion, livestock or humans. It has prompted Tanzanian anthropologist Charles Musiba to call for the creation of a new museum to reveal and display the historic prints. But foreign anthropologists question this idea ... as they did when the tracks were covered ... because Laetoli is several hours' drive into Ngorongoro Conservation Area, making guarding and maintaining any facility extremely difficult.

A file photo of the tracks is above. It would be a shame if they cannot be saved. Even though we have casts of them, the original is priceless.

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Early Australopithecines Used Stone Tools

Arizona State University is reporting that research done in Dikika, northern Ethiopia, by Curtis Marean and Hamdallah Béarat has determined that animal bone recovered from sediments that date to 3.4 million years old have cut marks indicating the use of stone tools. That would put these in the hands of Australopithecus afarensis. As Carol Hughes writes:

“This discovery dramatically shifts the known timeframe of a game-changing behavior for our ancestors,” said paleoanthropologist Zeresenay “Zeray” Alemseged, director of the Dikika project and director of anthropology at the California Academy of Sciences.

No hominin remains were found with the animal bone fragments that were uncovered 200 meters away from the site where Alemseged and a team discovered “Selam” (Lucy’s baby) in 2000. Lucy was discovered in 1974 a few miles north, near Hadar, by Donald Johanson, the world renowned ASU paleoanthropologist.

“There is no question that the announcement of stone tool use at 3.4 million years ago will unleash a flurry of controversy and genuine disbelief among some scholars,” said Johanson. “However, I believe the team has presented a convincing case of stone tool use during Lucy’s time.

While Johanson is sometimes given to hyperbole, he is quite correct that this represents a quantum jump in intelligence over any previous hominin form and will generate new models of early hominin behavior. Even if A. afarensis was just scavenging, the fact that they used tools to remove the meat they needed indicates considerable complex thought. The Nature article on this find will be forthcoming.

New 3.6 Million Year Old A. afarensis Remains

Science Daily reports that Yohannes Haile-Selassie's team in Ethiopia have found the remains of a 3.6 million year old Australopithecus afarensis individual that preserves enough of the post-cranium (below the head) to determine that bipedalism had completely taken hold of this species by this time. Of the individual, which is taller than Lucy (AL-288), he says this:

"As a result of this discovery, we can now confidently say that Lucy and her relatives were almost as proficient as we are walking on two legs, and that the elongation of our legs came earlier in our evolution than previously thought," he said in a statement. He explained, "

"All of our understanding of Australopithecus afarenis' locomotion was dependent on 'Lucy.' Because she was an exceptionally small female with absolutely short legs, this gave some researchers the impression that she was not fully adapted to upright walking. This new skeleton falsifies that impression because if 'Lucy's' frame had been as large as this specimen, her legs would also have been proportionally longer."

There is, thus, considerable variability in A. afarensis (this may yet revive the multiple species hypothesis that was put forth in the late 1970s about this material) This finding is expected, however, if the tracks at Laetoli are those of A. afarensis. We have good evidence that those are the tracks of a completely bipedal hominid.

If Ardipithecus ramidus ('Ardi') represents an ancestor to Australopithecus afarensis, then a considerable amount of evolution in bipedality occurred within 800 k years. A check of PNAS reveals that the paper is not out yet, but should be in a few days. Within the context of the debate concerning Ardipithecus' place on the fossil bush and the status of the reconstruction, it is important to remember what Owen Lovejoy wrote concerning Ardipithecus:

Ardipithecus ramidus now reveals that the early hominid evolutionary trajectory differed profoundly from those of our ape relatives from our clade’s very beginning. Ar. ramidus was already well-adapted to bipedality, even though it retained arboreal capabilities. Its postcranial anatomy reveals that locomotion in the chimpanzee/human last common ancestor (hereafter the CLCA) must have retained generalized above-branch quadrupedality, never relying sufficiently on suspension, vertical climbing, or knuckle walking to have elicited any musculoskeletal adaptations to these behaviors.

It is clear that, by 3.6 million years ago, those arboreal tendencies were gone. While it is still being debated whether or not Ardipithecus developed bipedality in the forest or in the forest fringe, the dessication of the landscape continued during the late Pliocene, and the remains of Kadanuumuu strongly suggest that early A. afarensis had completely adapted to this landscape.

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Australopithecus sediba Articles in Science

The Science Magazine articles on A. sediba are out. They are free for the time being. You just have to register at the site. The two articles cover the morphology of the finds as well as the geology of the Malapa Cave, in which they were found.
There is an extensive list of traits listed of both the cranium and face tabulated along with the other australopithecine species and early Homo. According to Berger and his team, it tells us the following:

The closest morphological comparison for Au. sediba is Au. africanus, as these taxa share numerous similarities in the cranial vault, facial skeleton, mandible, and teeth (Table 1). Nevertheless, Au. sediba can be readily differentiated from Au. africanus on both craniodental and postcranial evidence.

The face has the scooped appearance of australopithecines, with nice anterior pillars and the cranium is small, with a size of about 420 cubic centimeters. For reference, our heads are around 1400 cubic centimeters in size. On the Homo side, however, the vault is expanded and the face is considerably narrower than that of your average australopith. Compare it to this front shot of Australopithecus boisei specimen OH5, taken by David Brill. This lateral flaring of the cheeks is characteristic of all australopithecines to one degree or another and is not found in early Homo at all.

From the neck down, the skull has a mix of australopithecine and early Homo traits. The australopithecine traits include comparatively long arms, a somewhat conical-shaped rib cage and a small stature. On the other hand, it has a pelvic structure much more like later Homo, suggesting even better walking and running abilities.

Berger and his team have, I think, correctly placed this critter in the genus Australopithecus, but it clearly does have some characteristics that presage early Homo. What those mean is not yet clear but there was a general shift toward more modern characteristics in all of these hominids at around 2 million years ago.

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Laetoli Footprints Those of Completely Bipedal Human

Thirty years ago, a set of footprints was discovered in an ash layer at the African site of Laetoli and dated to 3.6 million years ago. This corresponded to the time range of Australopithecus afarensis but it was not sure whether or not this reflected the gait of afarensis, which was, at the time, thought to be somewhat bent-kneed and not truly bipedal in a modern sense. Now, Science Daily news has a story that reconstruction simulation research has determined that those individuals that made the tracks walked bipedally in a modern fashion. The author writes:

Since the Laetoli tracks were discovered, scientists have debated whether they indicate a modern human-like mode of striding bipedalism, or a less-efficient type of crouched bipedalism more characteristic of chimpanzees whose knees and hips are bent when walking on two legs.

To resolve this, [David] Raichlen and his colleagues devised the first biomechanical experiment explicitly designed to address this question.

The team built a sand trackway in Raichlen's motion capture lab at the UA and filmed human subjects walking across the sand.

"Based on previous analyses of the skeletons of Australopithecus afarensis, we expected that the Laetoli footprints would resemble those of someone walking with a bent knee, bent hip gait typical of chimpanzees, and not the striding gait normally used by modern humans," Raichlen said.

"But to our surprise, the Laetoli footprints fall completely within the range of normal human footprints," he added.

This is the next step from the bipedal gait found in Ardipithecus, which may have been reflected in the earliest australopithecine, A. anamensis and, perhaps, early A. afarensis. By this point, Bipedalism was the preferred means of getting around.

More on Ardipithecus ramidus

The NYT has a killer story by John Noble Wilford on the new Ardipithecus find (yes, I know, it is NYT but it was too good to pass up) with an associated graphic. It gives one an idea of just how transitional this find really is:

The Ardipithecus specimen, an adult female, probably stood four feet tall and weighed about 120 pounds, almost a foot taller and twice the weight of Lucy. Its brain was no larger than a modern chimp’s. It retained an agility for tree-climbing but already walked upright on two legs, a transforming innovation in hominids, though not as efficiently as Lucy’s kin.

Ardi’s feet had yet to develop the arch-like structure that came later with Lucy and on to humans. The hands were more like those of extinct apes. And its very long arms and short legs resembled the proportions of extinct apes, or even monkeys.

Here is the accompanying graphic, from the NYT.



Every so often, a find comes around and galvanizes the scientific world. This is one such find. A. afarensis is a good case for a transitional form. Ardipithecus ramidus is so much more. It also shows, in true evolutionary fashion, that the transition to bipedalism took place over a considerable period of time and happened in mosaic fashion.

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