Lets start with the Out of Africa scenario. Anatomically modern human
invaders from Africa entered Europe around 35-40,000 years ago. These
invaders were tropical Africans who brought with them, their genes, and
their hyper-tropical body shapes. What is meant by this is that in hot
countries there is a selective pressure in favor of body shapes that allow
heat to be removed. The classic heat tolerant body form is that of the
Watusi, a tall skinny people. Such body forms have a high surface
area/body mass ratio. Genetics controls the development of this body form.
It is not an environmentally acquired form. This is why short squat
Europeans living in Nigeria give birth to short squat children and why
Watusi living in New York city give birth to tall skinny offspring.
Apparently it takes millennia upon millennia for a group with one body form
to begin to convert to another. (more on this later.) Contrary to the
anatomically modern peoples, Neanderthals were short and squat. This is
widely beleived to have been due to the millennia of living in
cold,glaciate Europe Neanderthals were also hyper robust . This means
that their bones were exceptionally thick compared with anatomically modern
peoples. I want to use Stringer's words to illustrate what I think is a bit
of a double standard in anthropology. Stringer is a skeptic like Tattersall
and Schwartz. I can't find anthing quite this detailed in Tattersall or
Schwartz's books. Chris Stringer and Clive Gamble wrote:
"In their relatively heavy bodies the Neanderthals seem to conform to
Bergmann's rule, and in the shorter ends of their limbs to Allen's
rule.That the Neanderthal physique was partly determined by climate is
further supported by the slight differences in limb proportions between the
Neanderthals who lived in glaciated Europe and those who lived in the less
extreme climates of the Middle East."- p. 93
~ Chris Stringer and Clive Gamble, In Search of the Neanderthals, (New
York: Thames and Hudson, 1993), p.93
Bergman's rule is that body weights of an animals will tend to be greater
in colder climates. And Allen's rule is that their limb proportions will
be shorter. These rules have a wide application across many species. Thus
Stringer accepts the climate-induced selection pressure that created the
Neanderthal physique. How do we measure body form?
The body form is measured by numerous indices such as the crural and
brachial indices which are measurments of the limb lengths. The crural and
brachial index quantizes Allen's rule. The crural index is defined as
"the length of the tibia/ the length of the femur". One can multipy by 100
if he wants but it doesn't matter. Bergman's rule is measured by the
robusticity of the bones. This is because a being with greater body mass
needs more robust bones to support the extra weight. So, when looking for
differences between modern and Neanderthal we need to look at these types
of measures.
Here is how these rules apply to the Lagar Velho child. When we examine
various populations, fossil and modern, we find a range of values for the
brachial, crural and robusticity indices. Unfortunately the Lagar Velho
child's radius is incomplete so the brachial index can't be studied. Here
is the data presented by Stringer and Gamble (once again I want to use
STringer's data so that the skeptic's data is in play). This data is taken
from a chart on page 92 of Stringer and Gamble.
crural index Tibia/Femur length
modern peoples 79% in Lapps
86% in Black African groups
crural Mean annual temp C
index
Lapps 79% .25
modern Inuit 81.5% 4
average Neanderthal 79%
Belgium 82.5 10
S.African white 83.2 8.5
Yugoslav 83.75 8.4
American white 82.6 9.8
Kalahari Bushman83.4 18
New Mexico
Indian 84.6 14
S.African black 86.4 17
Arizona Indian 85.5 18
Melanesian 84.8 23
Pygmy 85.1 24.2
Egyptian 84.9 26.1
American Black 85.25 26
~ Chris Stringer and Clive Gamble, In Search of the Neanderthals, (New
York: Thames and Hudson, 1993), p.92
One sees at once that the subtropical peoples have a higher crural index
than those living in cold climates. This amazingly even applies to the
pygmies. Shortness is not at issue here. Body form is.
Lagar Velho has a crural index of .782 which as can be seen is lower than
all anatomically modern peoples including the Lapps. This value, as we
shall see is lower than ALL values for ALL anatomically modern, African
invaders.
What of the Lapps. I am going to claim that is is perilously close to
circular reasoning to use the Lapps as an analogue to compare with the
Neanderthals for one reason. Lapps occupy a region very close to the
former Neanderthal territories. If there has been any hybridization, the
low crural index of the Lapps might be indicative of that hybridization. In
other words one cannot tell if their squatness was due to genetic heritage
or the accumulation of the trait since the invasion of anatomically modern
peoples. The only way one can use the Lapps as evidence that a low crural
index means that the Lagar Velho child is nothing special is if they
ASSUME THAT THERE WAS NO HYBRIDIZATION. That is assuming the conclusion! I
would say that the Inuit make a better case for the acquisition of a low
crural index by the African invaders. This is because the Inuit were
nowhere near the Neanderthal homelands.
On the other hand, if one insists on using the Lapps as evidence that the
Lagar Velho child is within the range of variation of modern humans, then
it clearly argues in favor of Neanderthals being within modern human
variation in this regard. Neanderthal's averaged close to the Lapp average.
And if Neanderthals were within modern human variation, then there is
little reason to claim, as Tattersall and Schwartz claim, that Neanderthal
is a separate species. Thus they are hoisted on their own petard.
Tattersall and Schwartz seem to want to have it both ways.
About 100,000 years ago, anatomically near modern peoples appeared in the
Middle East at Skhul and Qafzeh Caves. So, we should look to these peoples
for the archetypes of the modern humans who invaded Europe. But we do need
to be careful in our analysis. Neanderthals lived in the Middle East along
with anatomically modern men and if there could be hybridization in Spain,
then it could have happened in the Mid East also. What do we find? We find
that, with one exception, all the Skhul/Qafzeh skeltons clearly have
subtropical body forms. Frayer shows the crural index on the Skhul/Qafzeh
peoples. There are only three individuals with enough skeletal matter to
make this measurement on. One has a crual index of 89, one has an index of
86 and Skhul V has an 80.[David W. Frayer, "Evolution at the European Edge:
Neanderthal and Upper Paleolithic Relationships," Prehistoire Europeenne,
2:9-69, Figure 9, p. 68 and p. 33.]
Obviously, one can argue that Skhul V shows that the range of the crural
index is so great as to make meaningless the measure on the Lagar velho
child. But in anthropology things are rarely that simple. Two things argue
agains this position. The Lagar Velho child has a crural index of .782
which is much smaller than the .80 of Skhul V. But then Skhul V has been
suggested to be an hybrid also. Johanson and Blake write of Skhul V:
Skhul V
"Others have subsequently interpreted Skhul V's anatomy as showing signs of
hybridization between modern and Neandertal populations. Hybridization is
difficult to demonstrate in fossils, and even if it did happen rarely, it
would not mean that Neandertals and modern humans were a single species.
The Tabun individuals clearly differed from those at Skhul, who were
undoubtedly on the cusp of becoming modern humans." ~ Donald Johanson and
Blake Edgar, From Lucy to Language, (New York: Simon and Schuster, 1997),
p. 242
It is interesting that the same trait is used to support hybridization with
Skhul V as with the Lagar Velho child.
I would suggest Johanson and Edgar are wrong in that if interbreeding did
occur biologically we are the same species. But, it seems that
hybridization is not to be the allowed, so any form that shows such
features is shoved one way or the other so that there are no hybrids. And
this is what was done to Skhul V.
Stringer and Gamble ignore Skhul V in their book. They write in
contradiction of the facts:
"The skeletons of the Skhul and Qafzeh samples are even more modern than
their skulls. And in contrast to the Neanderthals, their body proportions
are tropical rather than cold-adapted, with long forearms and tibiae [high
crural and brachial indices--grm] and an a average stature of about 1.83
m..." Chris Stringer and Clive Gamble, In Search of the Neanderthals, (New
York: Thames and Hudson, 1993), p.102
And Tattersall also ignores the outlier skeleton at Skhul. He writes:
"ESR dates on mammal teeth associated with the Hominid remains from Skhul
(virtually modern human) and Tabun (lightly built Neanderthal) have come
out around 100,000 years and 120,000 years, respectively." Ian Tattersall,
The Last Neanderthal, New York: Macmillan, 1995), p. 116
Obviously there is one skeleton that doesn't fit what they say {selective
use of data? Note here that I am using data like the Lapps and Skhul V
which don't initially fit within the position I am advocating and that is
what a person should do].
Now, if Stringer and Gamble are correct in ignoring Skhul V and dismissing
him as a possible hybrid, then the measurement of a Neanderthal-like crural
index becomes even more problematic for their position. They have to
explain how, among ALL upper Paleolithic anatomically modern humans, this
one child, this single individual achieved a Neanderthal-like body form
during the more moderate climatical times of 24,000 years ago when no other
anatomically modern person in Europe was able to achieve this body form!
How do I know this? Frayer again in Figure 9 p. 68 shows the crural
indices for European hominids from 90,000 years ago to the present. The
Skhul/Qafzeh peoples have the ranges I mentioned above. Neanderthals from
70,000 years ago have crural indices ranging from 76-81. Since the earliest
anatomically modern fossil dates from 34,000 years ago and is fragmentary,
the earliest anatomically modern crural index is from about 28,000 years
ago and has a value of 88. at 25,000 years ago there are7 specimens with a
crural index range of 84-88. At 24,000 years the range is 82-83. At 20,000
years ago the range is from 79-87 Between 15,000 and 10,000 the range is
from 81 to 90.5. I might point out that the 79 at 20,000 years ago is only
one individual. The next lowest above him at that time is 82. As Frayer
notes, the average crural index of anatomically modern humans has remained
around 84 throughout the past 30 millennia. Only as one gets into the
height of the last glacial age and on do we find anatomically modern
peoples with low cural indices. The finding of an individual like Lagar
Velho is clearly out of step with the rest of the data for European men. In
table form this data is
28 kyr 88
25 kyr 84-88
LV child
24 kyr 82-83
20 kyr 79-87 height of the glacial age
15-10kyr 81-90.5
The data for the ranges of the crural index shows that it takes up to 20
millenia before one sees the acclimatization to climate and this only after
the Wurm glaciation cooled Europe increasing the selective pressures on
modern humans. Thus the lack of low crural index modern humans prior to
20,000 years ago, which was the height of the last glaciation) argues
against the view that Lagar Velho is merely an extreme form of modern
human. 24,000 years ago, the time of the child, modern humans had been in
Europe for about 10,000 years and they maintained their typically
subtropical extremum (the lowest value in the population of fossils )crural
index for another 4,000 years.
What of robusticity? Duarte et al (Table 2)(in "The early Upper Paleolithic
Human skeleton from the Abrigo do Lagar Velho (Portugal)_ and Modern Human
emergence in Iberia," Proc. Natl. Acad. Sciences USA 96(1999):7604-7609.
The z scores of Tibia circumference divided by the length is 2.582 in Lagar
Velho, 2.405 in the La Ferrassie 6 Neanderhtal and .037 in Skhul I, the
African Invader. The same measure for the femur is 2.815 for Lagar Velho
I, 2.501 for the La Ferrassie 6 Neanderthal, 2.032 for the Roc de Marsal
Neanderthal and 2.643 for the Teshik-Tash Neanderthal. For the Invaders
from Africa the femur measurement is 1.646 for Qafzeh 10 and 1.148 for
Skhul I.
Clearly these robusticity measures place the Lagar Velho well within the
Neanderthal robusticity and separate from the African Invaders.
Similar analyses on the Tibia/femur length support the crural analysis
above. Lagar velho has a score of 2.044, La Ferrassie 6 2.415 and Skhul I,
0.493.
What Tattersall and Schwartz say? If I might be a bit pedantic in my
interpretation of their initial paragraph it says:
"Thus, although many students of human evolution have lately begun to look
favorably on the view that these distinctive hominids merit species
recognition in their own right as Homo neanderthalensis, at least as many
still regard them as no more than a strage variant of our own species, Homo
sapeins." Tattersall and Schwartz, "Hominids and Hybrids: The Place of
Neanderthals in Human Evolution," PNAS 96(1999):7117-7119.
If 'at least as many" anthropologists regard Neanderthals as a strange
variant of humans, then pedantically speaking, this is a majority of
anthropologists. By their own admission, their position looks to be a
minority position among their peers.
One of the weakest reasons for placing Neanderthal in a separate species
that I have ever seen comes from Tattersall and Schwartz' commentary. They
state:
"In contrast, if we see them [Neanderthals] as mere subspecific variants of
ourselves, we are almost obliged to dismiss the Neanderthals as little more
than an evolutionary epiphenomenon, a miknor and ephemeral appendage to the
history of Homo sapiens." Ibid.
This almost sounds like a religious reason, a doctrinal reason rather than
a scientific reason for making Neanderthals a separate species. Who cares
how we view them? What is important is the correctness of how we view them.
They do admit that if this is a hybrid, then we are the same species, no
more than a racial variant. Ibid.
Tattersall ans Schwartz critize the hypothesis because there is no dental
or cranial evidence of Neanderthal morphology. But they are criticizing
what Duarte et al freely state in their paper. Duarte say that the child
is a mosaic, not a morphing of form which is what Tattersall and Schwartz
seem to expect. And as a mosaic, some parts will be Neanderthal like and
some modern.
Tattersall and Schwartz say that this child is more like an F1 hybrid,
ignores the possibility that this very well might be an F1 hybrid. The
lastest Neanderthal dates somewhere around 28,000 years ago, merely 4,000
years before the Lagar Velho child. Are we really to believe that the
28,000 year old burial was the burial of the ABSOLUTELY LAST NEANDERTHAL
ON EARTH? Of course not. Neanderthals lived for some time after that but
we don't know how long. So, one can't entirely rule out that Neanderthals
lived until the 24,000 mark. Afterall, human remains are rather scarce
even during that time.
Tattersal and Schwartz spend a lot of time discussing the jaw, but very
little time (one paragraph) discussing the postcranial remains which is
where the major data supporting the hybridization hypothesis lies. Thus,
they spend most of their time on the parts that support their view and
little on the data that goes against their view. Yet their opinion is
claimed to have done away with the hypothesis. This is good sleight of
hand (don't look at the man behind the curtain), but very poor scientific
procedure. It is precisely the data supporting the Neanderthal
hybridization hypothesis upon which they should have spent most of the time.
They also left totally unchallenged the neck-shaft angle data in Duarte et
al which shows that the Lagar Velho femur is more similar to Neanderthal.
They claim. "And the tibia, like the femur, is hard to evaluate in the
absence of the epiphyses; it does not appear significantly different from
what one might expect to find in a robust modern human of this age."
Tattersall and Schwartz. ibid.
And they say, " The probability must thus remain that this is simply a
chunky Gravettian child, a descendant of the modern invaders who had
evicted the Neanderthals from Iberia several millennia earlier." Ibid.
To which I give a hearty "bull roar". Anatomically modern humans are
demonstrably less robust than the archaic variants of Homo sapiens. The
data I showed above and the data presented in Duarte et al clearly shows
that the Lagar Velho child is much more robust than African invaders. The
Lagar Velho child's legs are much more Neanderthal-like than ANY pre 22,000
year old African Invader. If this is no hybrid, where are all the other
anatomically modern fossils with similar crural indices and robusticities
from which this child could have received his genes? Or did the child self
create his own genetic heritage?