Muffler Falls Off Ford Pinto: Luskin on Dmanisi

I’ve been wondering what the creationist response to the new Dmanisi article in Nature would be. The Discovery Institute’s decrepit Ford Pinto gets pushed to the podium (sans muffler, a few wheels and a bumper or two). I say decrepit because Luskin’s post is, to put it charitably, pitiful. Finds at Dmanisi have been cropping up since sometime in the early 1990′s. The site itself dates to around 1.77 MYA based on 40Ar-39Ar dating as well as geomagnetic polarity studies. The site contains stone tools similar to the Oldowan core and flake industry found in East Africa. Skeletal material from a number of hominins have also been found there.

Creationists have a hard time dealing with the crania found at Dmanisi and Luskin’s new post continues that trend. Lusken is taking umbrage at a new paper, published in Nature, concerning the postcranial skeletal material found at Dmanisi. In the process of whining about Daniel Lieberman and John Noble Wilford manages to pretty much bungle both the new Nature article on Dmanisi and the recent article on Ileret.
The postcranial material has been attributed to four individuals (one adolescent and three adults) by Lordkipanidze et al. The adolescent material is associated with the D2700 crania. Some elements, representing a large individual, are associated with the D2600 mandible and some elements (from a smaller individual) are associated with the D3444/D3900 crania. The crania were evaluated in a previous paper by Rightmire et al – published in The Journal of Human Evolution in 2006. In that paper, the authors point out similarities to Australopithecus afarensis, Homo habilis and H. erectus. Most of the traits relating the Dmanisi material to A. afarensis or H. habilis were considered to be either size related or primitive retentions. Similarly, a number of the traits shared by the Dmanisi material and H. erectus are either primitive retentions or are variable in H. erectus and early Homo. Rightmire et al make the case that the Dmanisi material is, indeed, H. erectus by noting a number of traits shared with Asian H. erectus. If the Dmanisi material is H. erectus then there are a number of interesting implications relating to the variability of the H. erectus taxon (in cranial capacity, size, and the completeness of the postcranial adaptation to bipedal walking, or more specifically, long distance walking/running). In their summary Rightmire et al make six points. The last is the most interesting:

On morphological grounds, it can be argued that the group from which the skulls are drawn is close to a stem from which later more derived populations are evolved. As further comparative work is carried out, several hypotheses must be considered. One is that an early Homo population left Africa and settled in the Caucasus, where it was ancestral to the Dmanisi hominins. Dating does not presently rule out the possibility that H. erectus originated in Eurasia and that some groups then returned to Africa, where they evolved toward H. erectus ergaster. Also, both geographic considerations and the anatomy of the Dmanisi fossils are consistent
with the hypothesis that hominins reaching the Caucasus early in the Pleistocene are closely linked to the first inhabitants of Java and/or China.

It is in this context that the Ileret finds were announced and the Dmanisi material makes a brief appearance in the Spoor et al paper. In that paper Spoor et al argue that the Dmanisi material can not be considered transitional based on size or size related traits. In other words, H. erectus is more than an allometrically scaled up version of H. habilis.
This brings us back to the Dmanisi postcranial material. In summarizing their results Lordkipanidze et al state:

The following preliminary conclusions can be drawn: the morphology of the upper and lower limbs from Dmanisi exhibits a mosaic of traits reflecting both selection for improved terrestrial locomotor performance and the retention of primitive characters absent in later hominins (Supplementary Table 8). The length and morphology of the hindlimb is essentially modern, and the presence of an adducted hallux and plantar arch indicate that the salient aspects of performance in the leg and foot, such as biomechanical efficiency during long-range walking and energy storage/return during running, were equivalent to modern humans. However, plesiomorphic features such as a more medial orientation of the foot, absence of humeral torsion, small body size and low encephalization quotient suggest that the Dmanisi hominins are postcranially largely comparable to earliest Homo (cf. H. habilis). Hence, the first hominin species currently known from outside Africa did not possess the full suite of derived locomotor traits apparent in African H. erectus and later hominins.

So, what does Luskin make of this?.

Last month I discussed the fact that newly reported Homo erectus fossils predated fossils of “Homo” habilis, meaning that habilis could not possibly have been an evolutionary link between the Australopithecine apes and our genus Homo.

Luskin is misinterpreting the Ileret paper. In that paper a right maxilla, referable to H. habilis was announced. The maxilla was dated to 1.44 MYA and indicates that as there was some temporal overlap between H. habilis and H. erectus. The paper does not indicate that H. erectus predates H. habilis as a species. Luskin is flat out wrong on this.

I can imagine that both Wilford and Lieberman have subsequently received possibly non-fictitious memos [emphasis mine - afarensis] reminding them “Don’t question evolution to the public, plug evolution to the public!”, because both are now defending our knowledge of human evolution in articles that just came out this week.

Apparently, Dembski and Luskin have been sharing Cliff Notes on how to invent fake emails and memos.

According to Wilford’s NY Times article, these newly reported fossils, “had brains not much larger than those of a chimpanzee” and “[t]he small body size and small craniums, the upper limbs, elbows and shoulders were more like the earliest habilis specimens.” Of course habilis’s skeleton has been recognized as highly ape-like, so these features all appear very ape-like. Why do they claim this species is transitional? Supposedly, it’s all in the legs.
According to the Figure 3 in the Nature report, the femoral length is like that of a human or a gorilla (Fig. 3b). The tibial mediolateral distal width is like that of a chimp, human, or bonobo. Figure 3a reports that the tibia length is quite similar to that of a gorilla but different from that of humans. (Figure 3 also reports the length of an arm bone, as the humeral length resembles that of a human or perhaps a chimp (Fig. 3b).) Finally, the fossil footbones that were discovered are reported have some features that are like human feet, and others that are closer to the feet of modern apes.

In some ways, this is kind of correct. Unfortunately for Luskin, the correct part is what Wilford had to say. There are some primitive retentions in the Dmanisi upper limbs. For example, in the cranial orientation of the glenoid cavity (part of the scapula) and in the lack of humeral torsion (from Lordkipanidze et al):

Following this line of argument, the Dmanisi hominins would have had a more australopith-like than human-like upper limb morphology, and absence of humeral torsion in H. floresiensis would provide support for the hypothesis of long-term continuity of this plesiomorphic trait in Homo.

What about the lower limbs? Lordkipanidze et al measured the femurs and tibias of 22 humans, 30 chimps and 30 gorillas. The measurements are below. For the femur:
Humans: mean 381.9±22.9, range 337.0 – 434.0.
Chimps: mean 290.2±15.9, range 252 – 318.
Gorilla: mean 350.1±40.8, range 294.0 – 423.
For the Tibia:
Humans: mean 318.9±20.5, range 290.0 – 374.0
Chimps: mean 242.2±14.3, range 207.0 – 266.0
Gorillas: mean 281.5±29.7, range 241.0 – 334.0
They also took measurements on orangs, but those figures don’t seem to be reported in the supplemental results. Incidentally, for the Dmanisi material the numbers are femur length 386, tibia length 306. Clearly, there is some overlap between humans and gorillas in terms of the size of the femur and tibia. Simple linear measures are taxonomically uninformative – for the most part – something more, namely an analysis of the morphology, is needed. So either Luskin really doesn’t understand the material he is dealing with or he is deliberately obfuscating the issue. The figure 3 referred to occurs in a discussion of limb length proportions and body mass estimates. Here is what Lordkipanidze et al conclude based on that:

Limb proportions of the Dmanisi hominins, measured by femoral/tibial and humeral/femoral ratios (Fig. 3b, c and Table 1), were similar to those of modern humans, but also to those of earliest African Homo and to the BOU-VP-12/1 specimen dated to 2.5 Myr ago. Absolute hindlimb length of the Dmanisi hominins is greater than in australopiths and close to that of later Homo including modern humans. This may reflect selection for improved locomotor energy efficiency, as the cost of transport is inversely proportional to hindlimb length for terrestrial animals including bipeds.

Is anyone really surprised that hindlimbs were responding more quickly to demands on locomotion, while the forelimbs, freed from locomotory demands, were changing at a slower pace? Luskin makes a lot out of the overlap in dimensions (length, width, etc.) for the next couple of paragraphs clearly demonstrating he doesn’t understand the material.

Yet these leg and foot bones in many respects resemble modern apes as much as they resemble modern humans.

I’ve already addressed the femur and the tibia so let’s look at the foot:

D4110 is a well-preserved left talus. The neck is stout and expanded transversely but elongated compared to modern humans. The neck (horizontal) angle is small and similar to modern humans. The medial tubercle is strong and projecting, and the groove for the tendon of flexor hallucis longus is deep. This groove has a slightly oblique orientation, which is similar to great apes, whereas humans exhibit a more vertical orientation. D2671 and D3442 are subadult and adult right first metatarsals, respectively, with lengths at the lower end of modern human variation and elevated robusticity indices. The morphology of the head deviates from that known from apes and humans. It is spherical and exhibits a narrowing of the dorsal breadth of the articular surface. Head torsion is in the range of variation of subadult and adult modern humans and of OH8 (H. habilis). Two adult metatarsals III (D2021 and D3479) have a straight shaft, exhibit a high degree of torsion and have a dorsoventrally elongated cross-sectional shape, as in modern humans. Metatarsals IV (adult D4165 and subadult D2669) exhibit an elevated degree of torsion and dorso-ventral elongation. Adult metatarsal V (D4508) is short and at the lower end of modern human variation for its mid-shaft dimensions.

That is, verbatim (except for references), the entire section on the feet. There is only one trait that in the Dmanisi foot shows any similarity to the apes. That is in the orientation of the groove on the talus for the flexor hallucis longus. In the chimp and gorilla the flexor hallucis longus flexes the big toe and toes three and four. In humans the groove for this muscle is vertical while in apes it is more oblique. Otherwise, the foot displays the tranverse and longitudinal arches and adducted big toe characteristic of humans. So much for apelike feet.

In short, these are interesting new finds: Above the waist, they appear to be extremely ape-like. Below the waist, they seem to resemble modern apes as well as resembling modern humans. Yet this species post-dates the human-ape split and is being touted as a species that was evolving into a modern human, not a modern ape. What’s going on here?

What’s going on here is that you clearly do not know what the heck you are talking about.
References Cited
Postcranial evidence from early Homo from
Dmanisi, Georgia
David Lordkipanidze, Tea Jashashvili1, Abesalom Vekua, Marcia S. Ponce de Leo´n, Christoph P. E. Zollikofer, G. Philip Rightmire, Herman Pontzer, Reid Ferring, Oriol Oms, Martha Tappen, Maia Bukhsianidze, Jordi Agusti, Ralf Kahlke, Gocha Kiladze, Bienvenido Martinez-Navarro, Alexander Mouskhelishvili, Medea Nioradze & Lorenzo Rook
Vol 449|20 September 2007| doi:10.1038/nature06134
Anatomical descriptions, comparative studies and evolutionary
significance of the hominin skulls from Dmanisi, Republic of Georgia
G. Philip Rightmire , David Lordkipanidze , Abesalom Vekua
Journal of Human Evolution 50 (2006) 115-141
Implications of new early Homo fossils from Ileret,
east of Lake Turkana, Kenya
F. Spoor, M. G. Leakey, P. N. Gathogo, F. H. Brown, S. C. Anto´n, I. McDougall, C. Kiarie, F. K. Manthi & L. N. Leakey
Vol 448|9 August 2007| doi:10.1038/nature05986

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12 Responses

  1. Interesting indeed. I hope these findings lead to additonal expeditions to locate early homin remains in South Asia and Central and Southern Europe. As well as comparative studies of Homo georgicus and H. antecessor, H. heidelbergensis, and H. neandertalensis on the one hand, and H. georgicus and H. floresiensis on the other.
    It is amazing how a single site can change our knowledge to such a degree.

  2. Lusken is taking umbrage at a new paper, published in Nature, concerning the postcranial skeletal material found at Dmanisi.

    Is Nature publishing a critical comment from Luskin, or has Luskin limited his whining to blog pages? Oh, that’s right, the Memos probably tell the journal not to accept any critical comments.

  3. Alan – One can only hope. I know the Ileret find came as the result of a dedicated effort towards finding early Homo in East Africa.
    Mark – He’s whining on Evolution News and Views.

  4. Luskin “can imagine… possibly non-fictitious memos…” telling scientists, “Don’t question evolution to the public, plug evolution to the public!”
    Yeah. Can he imagine who would send such memos? Can he imagine why scientists would accept such bullying? I can imagine– actually, I know– any number of scientists who would scream censorship and restraint on academic freedom if they were sent anything remotely like those “possibly non-fictitious memos….”
    When ID can produce nothing better in the way of research than “possibly non-fictitious memos…” it has reached a dead end. There is nothing left there at all except P-A-R-O-D-Y.

  5. Afarensis – Now to get paleoanthropologists to think past the East Africa Mafia. :)

  6. Interesting find. I’m wondering how primitive hominins could have survived in Georgia. It gets cold there in the winter, this is far from the equator in central Eurasia. It routinely snows there. Not too sure what the climate was like 1.77 megayears ago but there were some ice ages in the pleistocene.
    Could they have made arctic style clothing such as the Eskimos? Did they have fire? That would help a lot. The Dmanisi hominids are old and described as small brained even for an H. erectus. Hard to imagine but who knows.
    This large brained modern H. sapiens would hate to spend a Georgian winter without some decent shelter and a fire.

  7. Interesting find. I’m wondering how primitive hominins could have survived in Georgia. It gets cold there in the winter, this is far from the equator in central Eurasia. It routinely snows there. Not too sure what the climate was like 1.77 megayears ago but there were some ice ages in the pleistocene.
    Could they have made arctic style clothing such as the Eskimos? Did they have fire? That would help a lot. The Dmanisi hominids are old and described as small brained even for an H. erectus. Hard to imagine but who knows.
    This large brained modern H. sapiens would hate to spend a Georgian winter without some decent shelter and a fire.

  8. Raven wonders “how primitive hominins could have survived in Georgia.” And askes, “Could they have made arctic style clothing such as the Eskimos?” Unlikely. But, like most animals that live in regions of winter snow, perhaps they changed from white to brown with the seasons.

  9. I’ve wondered whether Eurasian neanderthals and homo erectus didn’t have fairly thick pelts. Neanderthals are generally illustrated without a lot of body hair– because it makes them look more intelligent! (I know that doesn’t make logical sense. But I’m not a professional illustrator.) Could be similar reasoning for H. erectus.

  10. I doubt it. I suspect they both looked much more like us than most people like to imagine. After all, the Bible says we were specially created so there must have been a huge jump between us and any previous species, right?

  11. terry t–
    Think about what you’re writing, there. Have you actually seen neanderthal skeletons like the ‘old man’ of La Chappelle-aux-Saintes? They look HUGELY like us in their bone structure. The only scientific question is whether they were ancestors or close cousins of ours. H. erectus are not quite as strikingly similar, but the close connection is obvious to anyone who hasn’t been through a creationist brainwashing.
    Are you honestly trying to argue that if H. neandertalensis and H. erectus looked superficially dissimilar from us, due to an easily-mutated characteristic like body hair, that would make the literal truth of Genesis at all more probable?
    I don’t believe you meant to say that at all. But, it is kind of the way your post comes across.

  12. Actually, hoary, I was being deliberately silly. I was having a dig at the fact that even those anthropologists who consider tyhemselves atheists have been influenced by biblical origin beliefs. The idea we’re somehow descended from just two individuals or just a small group at most is widespread. Many Christian evolutionists must have breathed a sigh of relief when Eldredge and Gould came up with punk eck. They could once again believe we’re somehow isolated from the rest of biology and totally different.

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