more "human" or simply less neanderthal? "classic" vs "levantine"...

7
1– Noelle Tankard 2010 “Classical” European vs “Levantine” Near Eastern Neanderthals: Cladistic variation as regional and taxonomic identity It could be said that Neanderthals are at once the best and least known of fossil hominids. The literature regularly and systematically modifies descriptions of Neanderthals as “Classic”, prescribing the European specimens for comparative and definitive discussion while implying non-Classic, non- European Neanderthals somehow atypical. Yet, some of the best preserved and most significant of specimens are from the Near East. Often placed in apparent juxtaposition to Classical Neanderthals, these “Levantine” Neanderthals include Shanidar 1, Amud 1, Kebara 2, Tabun 1, and the Dederiyeh infants. In this essay, I hope to describe these specimens, after summarizing the relevant background regarding definitions and interpretations of Neanderthals, and to then briefly explore the nature and degree of the difference, should there be one, between Classical and Levantine Neanderthals. The Neanderthal type specimen was found in the Feldhoffer grotto of Neander Valley in 1856. Excavations over a century later found associated fragments that fit to the skullcap. (Johansen 2006, 242) Initially, Neanderthals were seen as a transitional phase through which humans had passed; frequently compared to chimpanzees, described as brutish, Neanderthals' primitive and savage features were emphasized, particularly the prominent brow-ridges and low-vaulted brain cases, emphasized to the exclusion of others. Fossils found in other regions were even labelled “Neanderthaloid”, the term serving as a generic pre Homo sapiens catch-all. The Broken Hill skull from Zambia was called the “African Neanderthal” upon discovery and the Solo skulls from Java referred to as “Eastern Neanderthals”. As the number of finds amassed and the body of data increased, interpretations became progressively more nuanced and less biased. (Trinkaus 1979) Their “primitive” status was gradually overturned: by the 80s, Neanderthals were commonly referred to as Homo sapiens neanderthalensis. Early genetic studies somewhat reverted this trend, as Figure 1: Composite Reconstruction (Sawyer & Maley 2005, 25) Figure 2:The Feldhoffer grotto skullcap, Neanderthal type specimen, shown with associated zygomaxillary fragment (Tattersall 2009) Figure 3: La Ferrassie, France (Johanson 2006, 9, 241)

Upload: noelle-tankard

Post on 02-Apr-2015

309 views

Category:

Documents


2 download

DESCRIPTION

Cladistic Variation as Regional and Taxonomic Identity

TRANSCRIPT

Page 1: More "human" or simply less Neanderthal? "Classic"  vs "Levantine" Neanderthals

1– Noelle Tankard 2010

“Classical” European vs “Levantine” Near Eastern Neanderthals: Cladistic variation as regional and

taxonomic identity

It could be said that Neanderthals are at once the best and least known

of fossil hominids. The literature regularly and systematically modifies

descriptions of Neanderthals as “Classic”, prescribing the European specimens

for comparative and definitive discussion while implying non-Classic, non-

European Neanderthals somehow atypical. Yet, some of the best preserved and

most significant of specimens are from the Near East. Often placed in apparent

juxtaposition to Classical Neanderthals, these “Levantine” Neanderthals include

Shanidar 1, Amud 1, Kebara 2, Tabun 1, and the Dederiyeh infants. In this

essay, I hope to describe these specimens, after summarizing the relevant

background regarding definitions and interpretations of Neanderthals, and to

then briefly explore the nature and degree of the difference, should there be

one, between Classical and Levantine Neanderthals.

The Neanderthal type specimen was found in the Feldhoffer grotto of

Neander Valley in 1856. Excavations over a century later found associated

fragments that fit to the skullcap. (Johansen 2006, 242) Initially, Neanderthals

were seen as a transitional phase through which humans had passed; frequently

compared to chimpanzees, described as brutish, Neanderthals' primitive and

savage features were emphasized, particularly the prominent brow-ridges and

low-vaulted brain cases, emphasized to the exclusion of others. Fossils found in

other regions were even labelled “Neanderthaloid”, the term serving as a generic

pre Homo sapiens catch-all. The Broken Hill skull from Zambia was called the

“African Neanderthal” upon discovery and the Solo skulls

from Java referred to as “Eastern Neanderthals”. As the

number of finds amassed and the body of data increased,

interpretations became progressively more nuanced and

less biased. (Trinkaus 1979) Their “primitive” status was

gradually overturned: by the 80s, Neanderthals were

commonly referred to as Homo sapiens neanderthalensis.

Early genetic studies somewhat reverted this trend, as

Figure 1: Composite Reconstruction (Sawyer & Maley 2005, 25)

Figure 2:The Feldhoffer grotto skullcap, Neanderthal type specimen, shown with associated zygomaxillary fragment (Tattersall 2009)

Figure 3: La Ferrassie, France (Johanson 2006, 9, 241)

Page 2: More "human" or simply less Neanderthal? "Classic"  vs "Levantine" Neanderthals

mtDNA analyses supported a more distant relationship with modern human populations. Although debate rages as

to the nature of Neanderthals relationship with modern humans and proper classification, whether a species or a

subspecies, Neanderthals form a clear morphological group with distinctive traits. Trinkaus notes that “… one can

systematically examine the large corpus of Neanderthal fossils… [with] present knowledge of the anatomical

functions of bone and muscle… against a fuller chronological background… the picture that emerges is quite clear:

a human population complex with a special pattern of anatomical features that extends without interruption from

Gibraltar across Europe into the Near East and Western Asia” (1979, 91).

Classical Neanderthals are clearly distinct from present day Homo

sapiens, from contemporaneous African Homo sapiens, and from European

Upper Palaeolithic populations. The most common descriptions of

Neanderthal morphology are in terms relative to Homo sapiens and

diagnostic traits include the large supra orbital torus (brow ridge), occipital

“bunning” (at the back of skull, also known as the “chignon”, from a longer

and seemingly stretched shape), facial prognathism (or the jutting “muzzle”

of the mid-face projection), a long low brain case, larger cranial capacity, a receding frontal (appearing as a flat

forehead), a post-cranial skeleton overall more robust, lack of prominent chin, a distinct and robust mandible

including a large space behind the last molar (retromolar space) and unique hand morphology thought to indicate

differences in grip. That the definition of Neanderthal has always been based on the Western European specimens

is understandable historically, having been the first found, and known in the largest quantity. Focus on

phylogenetic taxonomy makes the Classical morphology all the more pertinent as it is in Europe where the greatest

distinction can be drawn between Neanderthal and other populations.

General understanding explains Neanderthal morphology as a climatic adaptation, the clade evolving

indigenously within Western Europe and later diffusing east

and south. Classical Neanderthals have been found in France,

Germany, Belgium, the Netherlands, and Spain – with finds in

Italy and Greece variously attributed. Neanderthals are also

known from Eastern Europe (at sites in Croatia, the Czech

Republic, Ukraine, Slovenia, Slovakia) and Western Asia

(Uzbekistan). Near Eastern “Levantine” Neanderthals, or

those yet found, seem to be younger than the Classical sites

and, depending on how one interprets the chronology,

younger even than the region's populations of Homo sapiens.

(Krause 2007)

The term “Levantine”, although commonly used in the

literature, is somewhat problematic both geographically and

politically. Technically, it refers only to Israel, Palestine, and

Jordan while frequently, it is used for the whole of the Near

East which stretches from the Nile to northern Iran. (Shea

2003) Those who do distinguish the Levant from the rest of

Figure 4: Teshik Tash, Uzbekistan (Johanson 2006, 230-231)

Figure 5: Map from Shea (2003); colour highlights added for emphasis

Page 3: More "human" or simply less Neanderthal? "Classic"  vs "Levantine" Neanderthals

the Near East do so with intention to note the Levant as the “entry point” from Europe for Neanderthal migration

“deeper” into the Near East (Vandermeersch 2007). Unlike Europe, where Neanderthals' inhabitation long pre-

dated the entry of Homo sapiens and only briefly overlapped, the Near East long been recognized as the most

likely place in which the two would have interacted. (Vandermeersch 2007; Shea 2008; Wolpoff 2001; Kramer

2001) Both geographic and chronological considerations inspire investigation into the potential and nature of

interaction; behavioural and genetic. Assemblages from Skhul and Qafzeh have produced specimens with traits so

indeterminate as to confound precise classification and necessitate investigation as to not only the number of

species represented, but the degree of variation expected and acceptable within a species. The majority of

discussion on Levantine Neanderthal populations has therefore focused on distinguishing them from nearby Homo

sapiens. For the sake of this discussion, I will consider only the most obvious of specimens, assigned by general

consensus unquestionably to the Neanderthal clade: Shanidar 1, Amud 1, Kebara 2, Tabun, and Dederiyeh.

The Shanidar Neanderthals consist of nine skeletons, seven of which are adults (Trinkaus 1982, 61). The

stratigraphy of the site is such to preclude precise dating but it is clear that the specimens span considerable

geographic time, with minimum possible ages ranging from 45 kyr to 60 kyr. While they cannot be considered a

single population, they nonetheless constitute a

“morphologically homogeneous sample”. (Trinkaus 1982,

62) Shanidar 4, the “flower burial” and Shanidar 3, whose

injuries have been interpreted as deliberately caused by

another hominid, are highly contentious. Shanidar 1, the

most complete, is considered typical of Levantine

Neanderthals, with other specimens frequently identified

by comparison. Shanidar 1 was 35-40 yrs at death and

survived serious injuries, likely concurrent, including a blow

to left side of head that may have blinded his left eye and

crippled, possibly paralysing, his right arm and leg which are not only withered but sustained multiple and severe

fractures. (Trinkaus 1982)

Amud 1 is the tallest Neanderthal known with the largest cranial capacity of any hominid; estimated 25

years at death, with an estimated height over 1.8 m and 1740 cc cranial capacity. ESR dating on an associated

mammal tooth suggests an age of 40 – 50 kyr. She bears a close affinity to Shanidar 1 – from which the

reconstruction was based – and possesses features commonly

described as “mosaic” including some quite similar to those of

specimens from Skhul and Qafzeh that have been classified as Homo

sapiens. Amud 1 has a “long narrow face” within the range of Classical

Neanderthals, although its brow-ridge is considerably more slender

and angles backward on each side of the face. The eye sockets have

sharply defined margins, as in modern humans, but the maxilla are

“less inflated” in the cheeks. The chin is more marked than typical of

Classical Neanderthals. Although the cranium is “perfectly round” from

Figure 6: Shanidar 1 (Trinkaus 1979, 123)

Figure 7: Amud 1 (Johanson 2006, 235)

Page 4: More "human" or simply less Neanderthal? "Classic"  vs "Levantine" Neanderthals

the rear view (a trait common to Classical Neanderthals) the occipital torus is curved more like that of modern

Homo sapiens. (Johanson 2006, 234)

Kebara 2, approximately 60kyr, is the most complete trunk

skeleton of a Neanderthal yet discovered with the first complete set of

ribs, pelvis, and vertebra ever found. Incredibly, it includes a hyoid

bone, identical to that of modern humans, which anchors the muscles

necessary for speech. Standing approximately 1.7m and 25-35 yrs at

death, he was found on his back in a shallow pit with his right arm

across his chest and left arm resting on his abdomen – possibly an

intentional burial. Although, overall more robust, he bears clear

similarities to Amud, Tabun, and Shanidar; his vertebrae and hyoid

identical to Homo sapiens but a massive mandible with a retro-molar

space and no discernible chin. (Johanson 2006, 232)

The Tabun 1 female is possibly the oldest deliberate burial, and

possibly the oldest Levantine

Neanderthal. Unfortunately, her stratigraphic position is controversial and the

dating unclear; the specimen could be 134±8 kyr or, if an intrusion from a higher

context, a later contemporary of Amud and Kebara. The skull was greatly

fractured, leading many to question the reconstruction. (Zilhão 2010 Dec)

Akazawa's ongoing work with the two infants excavated at Dederiyeh

includes detailed reconstruction and what his team calls “resuscitation” complex

computer-based modelling of maturation and growth, based on Amud 1 and

clearly demonstrating their belief in the specimens' affinities. Dederiyeh 1,

estimated 60 kyr, with major damage to the face, was found on its back with arms

extended and legs flexed, with a limestone slab near the top of the head and a

triangular piece of flint hear the heart; quite probably an intentional burial.

Dederiyeh 2 was found associated with a wide variety of fauna and lithics. (Akazawa 2007)

Figure 10: Replica of Dederiyeh 1 in situ (Akazawa 2007)

Figure 11: "Resuscitation" of Dederiyeh infant (Akazawa 2007)

Figure 8: Kebara 2 (Johanson 2006, 233)

Figure 9: Tabun (Zilhão 2010 Dec)

Page 5: More "human" or simply less Neanderthal? "Classic"  vs "Levantine" Neanderthals

The commonalities of Levantine

Neanderthals are clearly addressed by

Vandermeersch (2007). As a group, they display

the majority of Classical traits, although not all

to the same “degree of development”. Many of

the Levantine features can often be

characterized as “entering the range of modern

human variation”. Morphologically, they are

united with higher skulls, a less oval transverse

contour, a suprainiac fossa larger and less deep.

Generally, they display less occipital bunning,

their occipitals are less convex and the occipital

torus less prominent; their skulls are “less

stretched”. Levantine Neanderthals

demonstrate less facial prognathism: the

anterior root of the zygomatic arch occupies a

position more advanced, and the malomaxillary

in a different orientation, with a “bend at the

cheek”. As with the Classical specimens, the cranial capacity varies widely, with Amud 1 at 1740 cc and Tabun 1 at

1271 cc. Endo and Kimura (1970; in Vandermeersch 2007, 88) proposed that Near Eastern Neanderthals were

taller, but with current data, difficult to determine. The Levantine males are possibly taller than Classical males as

Amud 1, thought to be a female, reaches 1.78 m.

Although the ways in which the Levantine Neanderthals' features differ from those of Classical specimens,

with specific traits to be described as “intermediate” between Classical Neanderthals and Homo sapiens, the

assumption that Levantine Neanderthals are themselves somehow intermediate or transitional to Homo sapiens is

perhaps premature. The very phrasing of such a question – whether Levantine Neanderthals are more Homo

sapiens or simply less Classical – reveals the flaw in our definition of Neanderthal, based on the Classical

specimens, and intended to distinguish two chronologically distinct European populations. The populations of the

Levant are in no way so distinct. Multiple statistical treatments of the morphological traits of Near Eastern Late

Pleistocene “human” remains have failed to demonstrate clear grouping into distinct units. Kramer (2001) tested a

null hypothesis of two clades (Amud/Tabun and Qafzeh/Skhul) and Wolpoff (2001) not only failed to disprove a

similar null hypothesis that variation could not explained by taxonomic distinction, but demonstrated that there

was significantly greater variation within the Qafzeh/Skhul sample than between those samples and the Levantine

Neanderthals. It is clear that, whether or not this can be explained by hybridization, there has been a great under-

appreciation of the amount of expected variation.

Figure 12: Computer generated maturation model of Dederiyeh infant, based on Amud 1 (Akazawa 2007)

Page 6: More "human" or simply less Neanderthal? "Classic"  vs "Levantine" Neanderthals

While it is accepted that the Neanderthal type

occurred as an adaptation to the colder European

climate, the appearance of this type in the warmer

Levant has yet to be satisfactorily explained. While

it is possible, even likely, that Classical

Neanderthals simply discovered and appreciated

the warmer, less severe, and more hospitable

environment of the Near East – given that

adaptation to a particular climate in no way attests

to a preference for said climate – the mechanism

through which this migration and presumably subsequent morphological change occurred demands attention.

Perhaps it is mere geographical variation, through genetic drift or even a reversal of traits no longer advantageous

in a warmer climate, but attempts to evaluate the significance of the differences in these traits is trivial unless it is

preceded with an appreciation, if not a causal explanation, of the traits themselves. Within the Classical

Neanderthals, not all of the traits appear in the same combination, to the same degree; we have little

understanding, as of yet, to how they may be related to each other. As to how the Neanderthal “form” is genetic as

opposed to developmental is under constant re-evaluation. (Ponce de León 2001; Churchill 2001) That some of the

anatomical features present in absolute – binary; present or not – while others display along a continuum further

complicates the issue. Most troubling for phylogenetic and taxonomic models is our current inability to clearly

distinguish between homologous and derived traits. To discuss these issues in reference to the anatomical traits

themselves is unfortunately not within the bounds of this paper, but occipital bunning is a prime example. Gunz

(2007) discusses the “range of morphological patterns” to which the term “bunning” is indiscriminately applied,

noting that not only is there debate as to definition, identification, and measurement of one of the most

ubiquitous and decisive of Neanderthal traits, but that the same effect can be achieved through a variety of

pathways involving differing cranial architecture.

Neanderthal traits are generally discussed as if a complete package, “the Neanderthal pattern” - and

specimens found lacking are often dismissed as unclassifiable. We have oversimplified the situation by deliberately

disregarding that which does not fit a prefabricated, perhaps arbitrary, designation. The underlying question – of

just how much variation a taxonomic entity can be expected to demonstrate – is of critical interest for not only

understanding Neanderthals, but palaeoanthropology at large. The fact that the issue is unresolved is more than

regrettable given our relationship with Neanderthal clade; the vast number of specimens and the extraordinarily

high degree of resolution, unmatched in hominid taxa, creates an inspiring opportunity to come to grips with such

variation.

Figure 13: (Trinkaus 1979)

Page 7: More "human" or simply less Neanderthal? "Classic"  vs "Levantine" Neanderthals

Bibliography

Aiello, L. and C. Dean (2002) An Introduction to Human Evolutionary Anatomy, London: Academic Press, ElsevierAkazawa, Takeru (2007). The Dederiyeh Neanderthal [online]. [Accessed 4/12/2010]. <http://www.kochi-

tech.ac.jp/akazawa/english/>Churchill, S. (2001) Hand morphology, manipulation, and tool use in Neanderthals and early modern humans of the

Near East, Proceedings of the National Academy of Science 98: 2953-2955Gunz, P and K. Harvati (2006) The Neanderthal “chignon”: Variation, integration, and homology, Journal of Human

Evolution 52: 262-274Johanson, D. and B. Edgar (2006) From Lucy to Language. New York: Simon & Schuster.Kramer, A. Et al (2001) Out of Africa and into the Levant: replacement or admixture in Western Asia? Quaternary

International 75: 51-63Krause, J. Et al (2007) Neanderthals in central Asia and Siberia, Nature 902-904Ponce de León, M. S. and C. P. E. Zollikofer (2001) Neanderthal cranial ontogeny and its implications for late

hominid diversity, Nature 412: 534-538Sawyer, G.J. & B. Maley (2005) Neanderthal reconstructed. Anatomical record. Part B, New anatomist, 283:23-31

Shea, J. (2008) Transitions or turnovers? Climatically-forced extinctions of Homo sapiens and Neanderthals in the east Mediterranean Levant, Quaternary Science Reviews 27: 2253-2270

Shea, J. (2003) Neandertals, Competition, and the Origin of Modern Human Behavior in the Levant, Evolutionary Anthropology 12:173–187

Tattersall, Ian (2009). The Feldhofer skullcap [online]. [Accessed 3 December 2010]. Available from: <http://www.amnh.org/news/wp-content/uploads/2010/02/zygomatic.jpg>.

Trinkaus, E. and M. R. Zimmerman (1982) Trauma Among Shanidar Neandertals, American Journal of Physical Anthropology 57:61-76

Trinkaus, E. and W. W. Howells (1979) The Neanderthals, Scientific American 241:122-123Wolpoff, M. And S. Lee (2001) The Late Pleistocene human Species of Israel, Bulletin et Mem de la Societe

d’Anthropologie de Paris 13: 291-310Zilhão, J. (2010 Dec) "The earliest moderns: a) Immediate ancestors b) Late Middle and Early Upper

Pleistocene Near Easterners". Lecture presented at University of Bristol, Bristol, UK.