Fossil_Evidence_for_the_Origin_of_Homo_s.pdf

Fossil Evidence for the Origin of Homo sapiens
Jeffrey H. Schwartz1
* and Ian Tattersall2
1
Departments of Anthropology and History and Philosophy of Science, University of Pittsburgh, Pittsburgh, PA 15260
2
Division of Anthropology, American Museum of Natural History, New York City, NY 10024
KEY WORDS paleoanthropology; human evolution; ‘‘archaic Homo sapiens’’; ‘‘anatomically
modern’’; Homo sapiens
ABSTRACT Our species Homo sapiens has never
received a satisfactory morphological definition. Deriving
partly from Linnaeus’s exhortation simply to ‘‘know thy-
self,’’ and partly from the insistence by advocates of the
Evolutionary Synthesis in the mid-20th Century that
species are constantly transforming ephemera that by
definition cannot be pinned down by morphology, this
unfortunate situation has led to huge uncertainty over
which hominid fossils ought to be included in H. sapiens,
and even over which of them should be qualified as ‘‘ar-
chaic’’ or as ‘‘anatomically modern,’’ a debate that is an
oddity in the broader context of paleontology. Here, we
propose a suite of features that seems to characterize all
H. sapiens alive today, and we review the fossil evidence
in light of those features, paying particular attention to
the bipartite brow and the ‘‘chin’’ as examples of how,
given the continuum from developmentally regulated
genes to adult morphology, we might consider features
preserved in fossil specimens in a comparative analysis
that includes extant taxa. We also suggest that this per-
spective on the origination of novelty, which has gained
a substantial foothold in the general field of evolutionary
developmental biology, has an intellectual place in paleo-
anthropology and hominid systematics, including in
defining our species, H. sapiens. Beginning solely with
the distinctive living species reveals a startling variety
in morphologies among late middle and late Pleistocene
hominids, none of which can be plausibly attributed to
H. sapiens/H. neanderthalensis admixture. Allowing for
a slightly greater envelope of variation than exists today,
basic ‘‘modern’’ morphology seems to have appeared sig-
nificantly earlier in time than the first stirrings of the
modern symbolic cognitive system. Yrbk Phys Anthropol
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Our species Homo sapiens has never been subject to a
formal morphological definition, of the sort that would
help us in any practical way to recognize our conspecifics
in the fossil record. To understand why, a bit of history
is helpful. The earliest surviving comparisons between
humans and animals using both differences and similar-
ities are those of the Greek polymath Aristotle (see
review in Schwartz, 1999). On the subject of human dis-
tinctiveness, Aristotle wrote:
‘‘Now, man, instead of forelegs and forefeet, has, as we
call them, arms and hands. For he alone of the animals
stands upright, on account of his nature and ousia [ 5
‘‘substantial being’’ or ‘‘defining character’’] being divine,
and the function of that which is most divine is to think
and reason; and this would not be easy if there were a
great deal of the body at the top weighing it down, for
weight hampers the motion of the intellect and the com-
mon sense’’ (Aristotle, 1945, xxx IV. 12 693a25–31).
Although Aristotle’s comparisons were limited to
humans and other living animals, he nonetheless articu-
lated three major features—bipedalism directly, and the
freeing of the hands in locomotory behavior, and the rea-
soning power of the brain by implication—that would
long stand as defining characteristics of our species
H. sapiens, and would provide as well the morphological
cornerstones of the eventual discipline of paleoanthropol-
ogy. In Aristotle’s view, a Prime Mover pushed the psy-
che of each organism, on its rung of the Ladder of Life
(Scala Naturae), to follow its destiny and to strive to
achieve impossible perfection. Although perched on the
uppermost rung of this ladder, humans, no less than any
other organism, failed to achieve a perfect state.
During the Dark Ages that replaced the Greco-Roman
tradition of individual thinking and exploration with
spiritual inquiry and divine revelation, the Scala
Naturae was more or less directly transformed into the
Great Chain of Being, in which an ascendant ordering
from the inorganic through the organic world reflected
the creation story of Genesis (Lovejoy, 1942). The early
systematists who labored to elucidate this chain
achieved their goals through equally idiosyncratic classi-
fications. One way to recognize the nearly divine status
of humans was to exclude them altogether from the clas-
sification. This route was chosen in the 16th Century by
Konrad Gesner (the inventor of the genus rank), and
also in the 17th Century by Francis Willughby (see
Schwartz, 1999), who nevertheless had clearly consid-
ered human characteristics in his comparisons, describ-
ing as ‘‘man-like’’ a number of features he thought
aligned the broad categories of ‘‘baboon’’ and ‘‘monkey.’’
In 1632, Ioannes Jonstonus (Jonstonus, 1632) became
one of the first taxonomists to discuss humans directly
in comparison with other animals, but only more than a
century later were humans classified not in their own
higher category, but in the same group as other man-like
mammals.
In 1735, Carolus Linnaeus struck what to a religiously
minded ‘‘scientific’’ world was a deep blow to the sacro-
sanct, by placing the species to which he belonged within
*Correspondence to: Jeffrey H. Schwartz, Departments of Anthro-
pology and History and Philosophy of Science, 3302 WWPH, Univer-
sity of Pittsburgh, Pittsburgh, PA 15260. E-mail: jhs@pitt.edu
DOI 10.1002/ajpa.21443
Published online in Wiley Online Library
(wileyonlinelibrary.com).
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YEARBOOK OF PHYSICAL ANTHROPOLOGY 53:94–121 (2010)

a taxonomic group that John Ray had actually named
for other animals: the order Anthropomorpha (Linnaeus,
1735). Only later (Linnaeus, 1758) did Linnaeus change
the ordinal name to Primates, meaning ‘‘chiefs of crea-
tion.’’ Although raising the ire of other taxonomists, Lin-
naeus was really just taking a logical step. But as out-
raged as his fellow taxonomists were, Linnaeus had
rejected neither special creation, nor the belief that his
own species, which he dubbed H. sapiens, had been cre-
ated last among Primates and in the image of its God.
Still, it was not just in grouping humans in the same
taxon as other mammals that Linnaeus broke with broad
tradition. More specifically, it was in his presentation of
the genus and species H. sapiens that Linnaeus aban-
doned his usual practice of providing a diagnosis for
each taxon. For, his only comment about his own species
was: nosce te ipsum (know thyself).
TOWARD THE FIRST DIAGNOSIS OF H. SAPIENS
Nicholas Steno had demonstrated as early as 1669 the
structural similarities between fossil bones, teeth, and
shells, and their counterparts in living vertebrates and
invertebrates. But, well into the 19th Century, humans
were denied any antiquity beyond the historical present
as recounted in a literal reading of the Book of Genesis
(see review in Schwartz, 1999). Thus, when in the late
18th Century, Johann Friedrich Blumenbach (Blumen-
bach, 1969) published his treatise on the morphological
features that united all ‘‘races’’ of H. sapiens, his com-
parisons were solely among extant taxa. Although Blu-
menbach generally praised Linnaeus’s groundbreaking
taxonomic work, he felt not only that Linnaeus had been
too focused on features of the mammal dentition, but
also that he had left an unfortunate gap by not provid-
ing even a single feature on which to base either the ge-
nus Homo or the species H. sapiens. It was this lacuna
that Blumenbach set out to fill.
Blumenbach discussed, among other things, the
‘‘external conformation of the human body,’’ its ‘‘internal
conformation,’’ and ‘‘those points, in which man is com-
monly, but wrongly, thought to differ from the brutes.’’
On the first topic, Blumenbach discussed a number of
osteological features distinguishing humans from other
primates and that were indeed fundamental to a diagno-
sis of H. sapiens: 1) Erect posture that develops natu-
rally and spontaneously, which is associated with an
anteroposteriorly shallow but laterally broad thoracic
cavity, widely separated shoulder joints, short sternum,
and scapulae that lie posteriorly on a rib cage that does
not fully encase the viscera; 2) A broad and flat pelvis
with broad and expanded ilia in which the ossa coxae
(Blumenbach’s ossa innominata), together with the sac-
rum and its coccygeal bones, form a basin that cups the
viscera (according to Blumenbach, a ‘‘true’’ pelvis); 3)
Two hands, each perfect (harking back to Aristotle) in
possessing a long thumb (the basis for Blumenbach’s
order Bimana, in contrast to Quadrumana, which sub-
sumed the ‘‘four-handed’’ nonhuman primates; 4) Two
feet with large and nonopposable first toes; 5) Vertically
implanted lower incisors accompanied by serially
aligned, close-set, and short canines; 6) Molars with
rounded rather than pointy cusps; 7) A short mandible
with a prominent chin; and 8) A single (not twinned)
opening in the palate that is situated just posterior to the
upper incisors. Among soft tissue features, Blumenbach
suggested humans were unique in possessing swollen lips
and earlobes [though Schultz (Schultz, 1968) would later
point out that chimpanzees occasionally develop ear-
lobes]. Although Blumenbach disagreed with his col-
league Johann Wolfgang von Goethe over the significance
of the absence of a premaxillary bone in humans, the two
were intellectually united in the belief that the most im-
portant attribute separating ‘‘man’’ from the ‘‘brutes’’ is
reason—the same quality to which Edward Tyson (1699)
had resorted on discovering the anatomical similarities
between a juvenile chimpanzee and humans, and to
which others would repeatedly turn in their attempts to
capture the distinctiveness of H. sapiens.
TOWARD ACKNOWLEDGING HUMAN FOSSILS
AND HUMAN ANTIQUITY
The constraining influence Genesis had on considera-
tions of human antiquity was reflected in the silent
rejection by the scholarly community of Charles-Philippe
Schmerling’s (1833) astonishingly insightful interpreta-
tion of human-like bones from the Belgian cave sites of
Engis and Engihoul as both fossilized, and contempora-
neous with the remains of extinct mammals. Even when
Charles Lyell (1863) later studied these caves and came
to agree with Schmerling, the case for human antiquity
fell largely on deaf ears. Indeed, the discovery in 1857 of
the Feldhofer Grotto Neanderthal remains still failed to
fully resolve the issue of human antiquity.
The saga of this discovery is too well known to need
repeating in detail. But, it is nonetheless important to
emphasize that Carl Fuhlrott, into whose possession the
Neanderthal bones first came, and Hermann Schaaffhau-
sen, their scientific describer, were adamantly at odds
regarding their antiquity. Fuhlrott believed that their
state of mineralization and their apparent co-occurrence
with fossils of extinct mammals demonstrated their
ancientness. But despite describing them as different
from present-day humans in substantial aspects of their
preserved morphology, Schaaffhausen advanced a series
of arguments that culminated in a resounding rejection
of this individual’s antiquity. For Schaaffhausen, the
Feldhofer Grotto remains could be accommodated easily
by stories of barbaric and savage H. sapiens who once
inhabited Western Europe (Schaaffhausen, 1861).
The first analysis of the Feldhofer Grotto specimen by
an acknowledged evolutionist came in 1863, in Chapter
3 of Thomas Henry Huxley’s monograph Man’s Place in
Nature, ‘‘On some fossil remains of man.’’ Before turning
to the Feldhofer remains, Huxley introduced the speci-
mens from Engis and Engihoul. Although glossing over
both the Engis child’s partial skull and the material
from Engihoul, Huxley did discuss in some detail the
adult and partially complete Engis crania and accompa-
nied these passages with a lithograph that illustrates
clearly the morphological details of a bipartite brow
(Schwartz, 2006), emphasizing that the configuration of
the supraorbital region, in conjunction with general con-
tours of the weakly muscle-scarred braincase, indicated
that this partial cranium had ‘‘belonged to a man of a
low degree of civilization: a deduction which is borne out
by contrasting the capacity of the frontal with that of
the occipital region.’’
Turning to the Feldhofer Grotto skeletal remains,
Huxley listed a large number of differences distinguish-
ing the fossil skullcap from modern humans. Given his
theoretical predispositions toward the significance of
morphologically discrete features and evolutionary salta-
95
ORIGIN OF HOMO SAPIENS
Yearbook of Physical Anthropology

tion, as well as his rejection of Darwinian gradualism
(Schwartz 2005, 2006), one might well have expected
Huxley to conclude that here was an extinct relative of
modern humans. Instead, via some remarkable special
pleading, he claimed that it was possible to assemble a
sequence of human skulls, from around the world, which
represented a progression from the most primitive to the
most advanced. Having, thus, produced a graded series
based on perceived differences and similarities in cranial
shape, he could then declare that ‘‘A small additional
amount of flattening and lengthening, with a corre-
sponding increase of the supraciliary ridges, would con-
vert the Australian brain case [at the bottom of the se-
ries] into a form identical with that of the aberrant fos-
sil’’ (Huxley 1863, p 179–180). As a result, ‘‘the fossil
remains of Man hitherto discovered do not seem to me to
take us appreciably nearer to that lower pithecoid form,
by the modification of which he has, probably, become
what he is’’ (Huxley, 1863, p 183). In this way, the most
prominent comparative anatomist of his time simultane-
ously denied the distinctiveness of the Neanderthaler
and introduced the notion that the morphology of H.
sapiens encompassed an almost unimaginably broad
range.
A year later, William King (1864) took Huxley to task.
In his view, the distinct morphologies of the fossil speci-
men were without counterparts in any living human.
But even as discoveries mounted that showed the
Feldhofer specimen was no isolated occurrence, the influ-
ence of Huxley’s conclusions quietly grew. Indeed, the
mindset he fostered is still alive and well today. Still,
what we find perhaps most remarkable about the early
discourses on the Feldhofer Grotto remains, postcrania
included, is that all almost entirely neglected Blumen-
bach’s distinguishing features of H. sapiens. Only in one
of Huxley’s (1863) three chapters in Man’s Place in Na-
ture, ‘‘Man’s relation to the lower animals,’’ was Blumen-
bach even mentioned, and then merely to claim an alleg-
edly undue emphasis on external differences between
the quadrumanous primates and humans in their (hind)
feet. Despite those differences, Huxley argued, the skele-
tal details of the human foot narrowed the ‘‘gap’’
between Blumenbach’s Bimana and Quadrumana.
‘‘LUMPERS’’ VERSUS ‘‘SPLITTERS’’ AND THE
FATE OF H. SAPIENS
The intellectual environment of the late 19th and
early 20th Centuries also sanctioned the identification of
subsequently discovered human fossils as ‘‘racial’’ ante-
cedents of presumed modern races, from sites such as
Grimaldi Cave (northeastern Italy), Boskop (Southwest
Transvaal, South Africa), and Wadjak (East Java, Indo-
nesia), as early representatives of specific racial groups
of H. sapiens. In turn, this provided free license to lumi-
naries such as Sir Arthur Keith (e.g., Keith, 1931) to
publish evolutionary trees that not only schematically
depicted scenarios of racial differentiation, but also posi-
tioned individual fossils in distinct evolutionary lines
leading to modern racial groups.
Although the Piltdown forgery for decades complicated
interpretation of the Neanderthals, and especially of
Eugene Dubois’ Pithecanthropus erectus, the search for
human-like fossil remains proceeded apace. By the
1930s, not only had a plethora of Neanderthal specimens
been discovered at sites in western and eastern Europe
but diverse fossil specimens of other human relatives
had been unearthed at widespread locales: the Mauer
mandible in Germany (holotype of H. heidelbergensis); a
fairly complete skull and various other skeletal ele-
ments, from what is now Zambia, on which the species
name H. rhodesiensis was bestowed; an isolated molar
from a site near Beijing (then Choukoutien, now Zhou-
koudian) that served as the namesake of the genus and
species Sinanthropus pekinensis, into which a number of
partial crania, fragmentary jaws, and isolated teeth
were subsequently folded; and, from various sites in
South Africa (first, Taung, followed by Kromdraai, Sterk-
fontein, and Swartkrans), cranial and mandibular speci-
mens that became the holotypes of various species dis-
tributed among three different genera (Australopithecus,
Plesianthropus, and Paranthropus).
During the 1940s, the recovery of such diverse speci-
mens fueled the practice of bestowing new species and
even new genus names on each new fossil. Thus when,
in the 1950s, the systematist Ernst Mayr turned his
sights onto the still-nascent field of paleoanthropology,
he found himself dumbfounded and befuddled by a
‘‘bewildering diversity of names’’ in its literature. Follow-
ing in the footsteps of Theodosius Dobzhansky (Dobz-
hansky, 1944), the geneticist and fellow architect of what
became known as the Evolutionary Synthesis—who
advanced the notion that the capacity for culture
removed all hominids from evolutionary processes that
would otherwise lead to divergent speciation—Mayr
waded vigorously into the arena of human evolution.
Mayr’s reasons for suggesting that human evolution
was a single, nondiversifying continuum of change were
these. An educated systematist would recognize that,
regardless of apparent morphological differences, all
hominids possessed the same adaptation: bipedal locomo-
tion. Because this systematist would also know that a
genus is defined by the ecological specializations of its
constituent species, all hominids should be subsumed in
the genus Homo because they all uniquely share the
same locomotor form. Further, present-day H. sapiens is
an incredibly varied and geographically widespread spe-
cies that has successfully occupied all available eco-
niches. By extension, hominids of the past must have
been as morphologically variable as living humans, if not
more so. Because, as he (Mayr, 1942) had previously
argued, diversifying speciation (as opposed to linear
transformation) requires that subspecies (defined as
incipient species) had to invade vacant econiches for new
selection pressures to orchestrate their gradual acquisi-
tion of new adaptations, hominids were not, and would
never become, taxically diverse.
As a result, Mayr concluded that, because only one
species of hominid would have existed at any point in
time, the entire course of human evolution could be
characterized as a highly variable, polymorphic contin-
uum of transformation comprised of three time-succes-
sive species (Mayr, 1950). These were H. transvaalensis
(for the earliest hominids, which were then only known
from South African sites), H. erectus (which subsumed
Sinanthropus, Pithecanthropus, and the Mauer jaw),
and H. sapiens (everything younger than H. erectus, or
for whatever reason not considered to be part of it; these
included the Neanderthals and the Ngandong specimens
from Java). In striking contrast to Blumenbach’s focus
on features that might distinguish the species sapiens
from other mammals, Mayr’s argument is interesting in
that it presumes a transformation series of species; spe-
cies neither morphologically defined nor diagnosed.
96 J.H. SCHWARTZ AND I. TATTERSALL

Instead, Mayr redirected the focus away from the spe-
cies, which until then had been the center of taxonomic
debate (e.g., see Huxley, 1940, 1942; Dobzhansky, 1941;
Mayr, 1942), and up to the genus, which he discussed
only in the broadest of terms, with regard to locomotor
behavior.
Mayr’s reason for disregarding species in the hominid
case may have had something to do with the repudiation
of what was then very recent history, the ugly face of
‘‘race’’ and ‘‘racism’’ (Schwartz, 2006). Thus, Mayr
claimed, echoing Darwin (1871), that even though we all
know that ‘‘Congo pygmies’’ and Watusi are members of
the same species, H. sapiens, without this prior knowl-
edge, even a competent morphologist confronted with the
skeletal remains of these ‘‘clearly different’’ humans
might easily, yet mistakenly, conclude that each human
group represented a distinctly different species. The
implication of Mayr’s folding a cornucopia of synchronic
but morphologically dissimilar specimens into time-suc-
cessive species was this: If groups of apparently dispar-
ate morphology are more or less universally agreed on to
be members of the same species, it is scientifically ludi-
crous (and racist) to attach biological, systematic, and
thus evolutionary meaning to the differences between
them.
Notwithstanding Mayr’s good intentions in reacting to
the horrors of ethnic cleansing that were part of World
War II, what is more relevant for the question ‘‘What
constitutes H. sapiens?’’ is Mayr’s promotion of a version
of Linnaeus’s ‘‘undiagnostic diagnosis’’ of our species:
nosce te ipsum. In other words, because we ‘‘know’’ that
short ‘‘Congo pygmies’’ and tall Watusi are members of
H. sapiens, there is no need to offer a morphological di-
agnosis of our species because, well, we just know who
we are. The same can be said of Huxley’s dismissal of
the Feldhofer Grotto individual. Huxley ‘‘knew’’ that the
historically recent specimens in his study were represen-
tatives of H. sapiens. Consequently, although he faith-
fully illustrated features that we might now regard as
restricted to H. sapiens, there was no compelling reason
for him to discuss or describe them in any detail. Rather,
he could concentrate on the thought experiment of how a
Feldhofer-shaped calvaria might be transformed into
that of what he considered the most archaic of human
races, the Australian Aborigine.
The major point here is that in the cases both of Hux-
ley and of Mayr, but especially of the latter, reifying a
purely intuited species actually leads one back to the
next lowest taxonomic rank: namely, the genus. For
Huxley, Homo was the only genus available; although for
Mayr, having compressed all previously proposed homi-
nid genera into one, Homo, this was his focus by default.
And the species, or the lineage of ever-changing chrono-
species, had become entirely secondary. Indeed, even
when Robinson’s (Robinson, 1953a) wide-ranging defense
of ‘‘the multitude of genera of Australopithecines pro-
posed by Broom’’ (Mayr, 1953) obliged Mayr to recognize
that ‘‘forms with Australopithecine characters existed
not only in South Africa, but also in East Africa and
Java’’ (p 281), and thus to envisage the possible coexis-
tence of, and competition between, the two hominid gen-
era Australopithecus and Homo), his focus remained on
the ecological adaptations of each genus (Mayr, 1963b).
Mayr’s vision of the genus Homo never wavered: an en-
tity within which each subsumed species became
smoothly and continuously transformed into another,
culminating in extant H. sapiens.
Despite Mayr’s partial recantation, the influence of his
original 1950 article is clearly evident in Leakey et al.’s
(1964) revised diagnosis of the genus Homo, which from
Keith onwards had been based largely on the assump-
tion that a ‘‘cerebral Rubicon’’ of brain size divided
humans from apes: This latter notion, in turn, clearly
reflected the emphasis of earlier (nonevolutionist) schol-
ars on ‘‘reasoning,’’ and thus on the brain as the ulti-
mate barrier between humans and the ‘‘brutes.’’
Although Leakey et al.’s revised diagnosis was unfortu-
nately filled with descriptors such as ‘‘variable,’’ ‘‘usu-
ally,’’ and ‘‘overlaps,’’ and phrases such as ‘‘very strongly
marked to virtually imperceptible,’’ it is significant that
they also emphasized many of the features that Blumen-
bach offered to distinguish the species H. sapiens from
other species of mammals—and which Mayr, via his ad-
aptation-centered model, later promoted as the system-
atic core of the genus Homo. According to Leakey and
colleagues, in Homo:
‘‘. . . the pollex is well developed and fully opposable
and the hand is capable not only of a power grip but of,
at the least, a simple and usually well developed preci-
sion grip. . .the anterior symphyseal contour varies from
a marked retreat to a forward slope, in which the bony
chin may be entirely lacking, or may vary from a slight
to a very strongly developed mental trigone: the dental
arcade is evenly rounded with no diastema in more
primitive members of the genus . . . the canines are
small, with little or no overlapping after the initial
stages of wear’’ (Leakey et al., 1964, p 8).
Such declarations as these emphasize that, although
Blumenbach’s efforts were confined to species diagnoses
that emerged from comparing living organisms, once
human fossils were brought into the systematic equation
features that had been presented as species-specific
became increasingly descriptive of a chronologically and
geographically diverse assemblage of specimens, none of
which necessarily represented H. sapiens. This opened
the way to the diagnosis of other species of the genus
Homo without reference to H. sapiens, which remained
as it always had been: simply, our species.
With that species firmly established as the pinnacle of
primate and, more narrowly, of hominid evolution, there
seemed, perhaps, even less need to define it. Because,
implicitly, all features of living H. sapiens must be
derived, or ‘‘advanced,’’ relative to any now-extinct homi-
nid relative. Because the accepted scenario featured the
theme of transition from H. erectus into the earliest
H. sapiens, this assumption anticipated a linear pattern
of acquisition of increasingly derived features in our line-
age. In turn, this expectation provided a springboard for
an array of publications that sought to trace a transfor-
mation or trend toward becoming totally ‘‘anatomically
modern’’ in, for example, metrical attributes of the denti-
tion (Wolpoff, 1971), the facial skeleton (Smith, 1984),
the postcranial skeleton and inferred bipedality (Rob-
inson, 1972), and brain size (Pilbeam, 1972). The title of
Pilbeam’s (1972) once-widely used textbook on human
evolution, The Ascent of Man, clearly implies a morpho-
logical transformation that is remorselessly advancing
toward the modern human condition.
What is most odd about this history is that anyone
actually familiar with even a small portion of the human
fossil record would ever even consider embracing Mayr’s
bizarrely influential assertions about human evolution.
For, the signal of that record, even as it existed in the
1950s and 1960s, did not support Mayr’s view at all.
97

Nevertheless, most paleoanthropologists not only suc-
cumbed to Mayr’s dictates but became intellectually con-
strained by them, apparently for the most part at least
as a result of the weight of authority Mayr had gained,
along with Dobzhansky and the paleontologist George
Simpson, with the triumph of the ‘‘hardened’’ version of
the Evolutionary Synthesis. This intellectual victory
resulted in the almost complete suppression of compet-
ing evolutionary ideas, emanating primarily from Ger-
many and the United Kingdom, that were in many ways
much more ‘‘synthetic’’ (Schwartz, 2009a,b; Schwartz, in
press) than the Synthesis itself. In the United States,
especially, the prominent physical anthropologist S. L.
Washburn (Washburn, 1951) was highly influential in
publicizing the virtues of replacing old-fashioned
‘‘typology’’ with ‘‘population thinking’’ (e.g., Simpson,
1949). As a result, paleoanthropologists seem not to have
noticed that the routine recognition and delineation of
three different chronospecies of Homo was becoming
ever more artificial and arbitrary as the hominid fossil
record expanded.
MULTIREGIONALISM AND THE
ORIGIN OF H. SAPIENS
A result of all this was that a vaguely defined but
intuitively attractive practice came into vogue, of con-
ceiving evolutionary change in terms purely of popula-
tions (Mayr, 1942, 1963a). This was neatly encapsulated
by Simpson in his comment that evolutionary change
was the ‘‘selection-influenced accretion of genetic
changes in populations’’ (Simpson, 1949, p 389). Indeed,
Simpson went so far as to dismiss non-Synthesis evolu-
tionary ideas as ‘‘typological systematics,’’ which he
equated with an equally unscientific pre-evolutionary
essentialist mindset. Although partly well intentioned,
in questioning the proliferation of named species that
differed from one another often only in morphological
minutiae, the focus on population thinking, whether in
neo- or paleozoology, raised a major operational problem.
Namely, how does a systematist work with the slippery
concept of the species as an entity that is always slightly
but continually changing, and whose boundaries at any
point in time are determined by a biological definition
imposed by entirely external constraints? For Simpson
(e.g., Simpson 1944, 1961) and Mayr (e.g., Mayr, 1969,
among others, the ‘‘lineage’’ thus became somewhat
interchangeable with the ‘‘species.’’ There is no need to
rehash here the debates over species definition that
ensued from the late 1970s through the 1980s (see Tat-
tersall, 2009). But it is worth repeating how influential
the hardened Synthesis was on paleoanthropology, and
thus on the determination of which fossil specimens
should be considered H. sapiens (Tattersall, 1986).
An early consequence of population thinking in paleo-
anthropology and modern human origins was seen in
later adaptations of Franz Weidenreich’s notion of
human evolution (Weidenreich, 1946, 1947) that por-
trayed morphologically disparate and geographically far-
flung fossils as the ancestors of living races of H. sapiens
currently occupying the same regions of the Old World.
What held these oddly assorted specimens together as a
single hominid species, despite their striking morphologi-
cal differences, was the Mayrian notion that some
amount of gene flow had maintained the biological link
between these lineages. The evolutionary unity of
diverse agglomerations of fossils as members of one and
the same species was, thus, derived from an unknown
degree of presumed genetic continuity, whereas the mor-
phological differences among them were seen as reflect-
ing each group’s partial geographic isolation and adapta-
tion to different environmental circumstances.
An extreme interpretation of the regional racial conti-
nuity model pervaded the work of the much-reviled Carl-
ton Coon (e.g., Coon, 1966), but more recently Milford
Wolpoff and colleagues have maintained a recognizably
Weidenreichian multiregional model, with the origins of
modern human population diversity rooted in H. erectus
(Thorne and Wolpoff, 1982; Wolpoff, 1989b, 1992, 1996;
Wolpoff et al., 1994b, 2006; Frayer et al., 2006). The pri-
mary assumption on which Wolpoff and his colleagues
rely is the existence of continually changing and occa-
sionally interbreeding and gene-exchanging lineages
within a species exhibiting morphological variations that
are due to differing ecogeographical circumstances (e.g.,
there is a Neanderthal phase in Europe and the Near
East, but not in Asia). From this perspective, these
authors ultimately argued that if H. sapiens is today the
result of nearly 2 million years of post-H. habilis lineage
transformation, it is nonsensical to recognize H. erectus
as a distinct taxon. Rather, if human evolution after
H. habilis and into the present was indeed continuous
and genetically interwoven, one should refer all non-
H. habilis specimens to the species to which their living
descendants belong: namely, H. sapiens.
Erik Trinkaus’ (2006) scenario for H. sapiens origin is,
in essence, a version of the multiregional model. How-
ever, rather than referring specifically to fossils that
other paleoanthropologists might consider representative
of distinct taxa, Trinkaus keeps his language vague.
Consequently, his (p 598) ‘‘general model of Pleistocene
genus Homo phylogeny’’ begins with the emergence of
‘‘early Homo’’ in Africa during the late Pliocene, followed
in the early Pleistocene by the dispersal of populations
of early Homo throughout Africa and into Southern Eur-
asia, extending from the Atlantic to the Pacific by the
end of the early Pleistocene. ‘‘Archaic Homo’’ of the Mid-
dle Pleistocene expanded this range geographically and
acquired regional variations in craniofacial morphology
and body proportions in the process. Trinkaus explains
this supposed transformation from the perspective of a
populational emphasis on ‘‘intraspecific differentiation
through isolation-by-distance’’ (p 598).
For Trinkaus, the process of regional differentiation
continued into the late middle and early late Pleistocene.
He finds evidence of this in the appearance of ‘‘late ar-
chaic humans (Neanderthals)’’ in Western Eurasia, of
‘‘less-well-documented late archaic humans’’ in Central,
Southern, and Eastern Asia as well as in northwestern
Africa, and of ‘‘early modern humans’’ primarily in East-
ern Africa. Rejecting cladistic theory and methodology
with the assertion that this approach to phylogenetic
reconstruction is tautological, Trinkaus (Trinkaus, 2006)
turns to the traditional stratophenetic approach (Gin-
gerich, 1976) to determining character polarity: i.e., an
accepted temporal sequence of fossils is the true and
unerring arbiter of primitiveness versus derivedness.
From this transformationist perspective, Trinkaus con-
cludes that paleoanthropologists who embraced a cladistic
orientation misinterpreted Neanderthal features as being
derived and those of modern humans as being primitive,
when things were clearly the other way round.
The counterpoint to a multiregional model (the single-
origin, out-of-Africa notion) has been championed by C. B.

Stringer (Stringer et al., 1984; Stringer and Andrews,
1988; Stringer and McKie, 1996), in part on the basis of
late Pleistocene hominid fossils, but also because mito-
chondrial DNA sequence data were interpreted to indi-
cate a single African origin for all modern human popula-
tions (Vigilant et al., 1991; Hedges et al., 1992; Stoneking,
1993). [Because the assumptions underlying the use of
mitochondrial DNA in phylogenetic reconstruction are
still debated (e.g., Awadella et al., 1999; Hagelberg, 2003;
Schmitz et al., 2005), we shall deal here only with the rel-
evant fossils and their morphology.]
Stringer and colleagues began by embracing specimens
primarily from the late Pleistocene Levantine sites Jebel
Qafzeh and Skhūl and the penecontemporaneous African
sites Omo-Kibish (Ethiopia) and Border Cave (South
Africa) as representatives of early H. sapiens. They then
took these specimens as evidence of an African origin of
modern humans to the exclusion of Neanderthals, which
they accepted as an independent entity marked by
numerous apomorphies. Although Stringer and col-
leagues did not provide any unifying features unique to
the Levantine and African specimens, they allocated
them to the species H. sapiens because all possess highly
vaulted neurocrania, relatively small faces, and thin cra-
nial bone. They additionally suggested that a feature
unique to extant H. sapiens is that each superciliary
arch is comprised of two distinct moieties (i.e., is bipar-
tite).
This configuration contrasts, for example, with the Ne-
anderthal brow, which is characterized as relatively uni-
formly tall and smoothly continuous from side to side.
Recently, we have provided an alternative description of
this region in extant H. sapiens (e.g., Schwartz and Tat-
tersall, 1996b, 1999a, 2000b), as consisting of a swollen,
anteriorly facing ‘‘butterfly-shaped’’ mounded region, of
which the ‘‘body’’ coincides with the glabellar region and
whose ‘‘wings’’ are delineated or undercut obliquely and
superolaterally by a more planar lateral portion whose
inferomedial extremity may coincide with the supraorbi-
tal notch/foramen.
Schwalbe (1901), who had earlier considered a bipar-
tite brow a feature of H. sapiens, also mentioned that
some specimens in his study did not express much if any
morphological detail in the supraciliary/supraorbital
region. We are fully aware of the range of expressed
supraorbital detail in H. sapiens from faint to marked,
but we also appreciate that ‘‘faintly developed’’ often
characterizes females of various extant populations (see
Schwartz, 2007b); even so, some trace of a glabellar but-
terfly is normally palpable. Consequently, because degree
of expression of the ‘‘brow’’ and various other sexually
dimorphic features of H. sapiens represent states of de-
velopmental continuum that spans between the hypo-
and hyperostotic, we suggest that it is more biologically
relevant to focus on the ‘‘glabellar butterfly’’ rather than
the supraorbital notch as reflecting the presence of a bi-
partite brow. Otherwise, because the nonclosure of this
notch to form a foramen is (primitively) widespread
among anthropoid primates (Schwartz, 2007b), an espe-
cially pronounced notch, as in, e.g., KNM-ER 1813, may
be erroneously taken as evidence of the bipartite configu-
ration. Interestingly, although Stringer and colleagues
are often perceived as radical opposites to the multire-
gional school of thought, they do converge in a mutual
acceptance of a number of fossil specimens attributed to
‘‘early’’ (as opposed to ‘‘archaic’’) H. sapiens. We will
return to this in a moment.
IN SEARCH OF THE ORIGINS OF H. SAPIENS
If H. erectus indeed gradually transformed into H.
sapiens, the question arises of when and where this
occurred. Historically, this has been particularly perplex-
ing because, when all Asian specimens of generally late
to middle Pleistocene age were collapsed into the single
taxon H. erectus, together with the apparent contempo-
rary represented in Europe by the Mauer jaw, it
appeared that the geographical range of this extinct
hominid had once extended across most of the vast Eura-
sian continent. Indeed, this prediction seemed to have
been validated with the 1960s discovery at Olduvai
Gorge in Tanzania of a ca. 800 ka calvaria (OH 9), which
many paleoanthropologists thought was remarkably ro-
bust, but yet with H. erectus-like features. Among those,
most characteristics most frequently remarked in this
context were the long and lower cranial vault, the mas-
sive and ledge-like brows, a somewhat distended occipi-
tal, and the ‘‘puffed out’’ cranial sides with margins
delineated by rugose temporal muscle markings (e.g., see
reviews in Santa Luca, 1980; Schwartz and Tattersall,
1999b, 2000c, 2003).
From Swartkrans, South Africa, a small (compared
with Paranthropus) mandible that was originally attrib-
uted to ‘‘Telanthropus capensis’’ was allocated to H. erec-
tus largely for the reason that something this small had
to be Homo—and the only species of Homo available at
the time was H. erectus (Robinson, 1953b). When,
approximately two decades later, much older specimens
were discovered in the area of Koobi Fora (especially the
crania KNM-ER 3733 and ER 3883) on the east shore of
Lake Turkana, Kenya, and then at Nariokotome on the
west shore (the skull, mandible, and unusually complete
postcranium of KNM-WT 15000), the range of this spe-
cies thus appeared firmly to include the African conti-
nent and to span virtually the entire Pleistocene. Fossils
subsequently recovered from the 1.8 Ma site of Dmanisi,
Republic of Georgia, have been suggested as filling in
the geographical ‘‘gap’’ in the record of H. erectus (Right-
mire et al., 2006).
But although one might argue for the existence of a
geographically and even temporally wide-ranging species
H. erectus, this does not demonstrate that H. erectus
actually ‘‘evolved’’ into H. sapiens. Indeed if, as by sys-
tematic necessity we must, we turn to the type specimen
of H. erectus (the Trinil 1 skullcap) for the defining char-
acters of this species, we are obliged at the very least to
entertain the possibility that its array of apparent apo-
morphies [such as the smooth transition from superoin-
feriorly thin and nonprotruding but laterally continuous
brows into the low and long frontal behind, the depres-
sions on either side of bregma that give the false impres-
sion of a definitive elevation, the distinctly ‘‘V’’-shaped
occipital protrusion, the ‘‘lamination’’ of temporal bulges
on the sides of the cranial vault, and the development of
a neurocranium that when viewed from behind is wider
than tall (Schwartz and Tattersall 2000c, 2003)] preclude
it from being ancestral to any other known species of
Homo, H. sapiens included (e.g., see Santa Luca, 1980;
Schwartz and Tattersall, 1999b, 2000c, 2003).
No less important for this discussion is the possibility
of greater taxic diversity represented among specimens
attributed to ‘‘H. erectus.’’ For instance, although the
allocation of East African specimens to the species H.
ergaster (Groves and Mazák, 1975) might have seemed
radical to some paleoanthropologists, the obvious mor-
99

phological differences among the three specimens usu-
ally presented as representing this taxon, KNM-ER 3733
and ER 3883 and KNM-WT 15000, may additionally be
systematically relevant (see Schwartz and Tattersall,
1999b, 2000c, 2003). Not to mention, of course, the fact
that the type specimen of H. ergaster is a mandible
(KNM-ER 992) that differs in dental morphology from
WT 15000 (Schwartz and Tattersall, 2000c, 2003). In
general, though, the tendency in paleoanthropology has
been to preserve H. erectus as a geographically wide-
spread and morphologically very variable species that
precedes the emergence of H. sapiens (e.g., Lieberman et
al., 2002).
Clearly, it will take time to climb out from under the
shadow of Mayr’s idea of the genus as a rank reflecting
broad ecological adaptation, in this case represented by
‘‘modern’’ body proportions and bipedalism. Witness, for
instance, Wood and Collard’s (1999) thoughtful attempt to
define the genus Homo on the basis of ‘‘striding bipedal-
ism.’’ Although laudably trying to define, or at least to
delineate, the parameters of this locomotor construct in
the broad context of overall body proportions (the skeletal
‘‘forest’’), this upward taxonomic focus neglected also to
take into consideration specific differences of skeletal,
especially pelvic and femoral, morphology (the skeletal
‘‘trees’’). Nevertheless, inspection of pelvic and, especially,
femoral morphological detail reveals that some of the very
features that have for decades now been noted as specific
only to australopiths (e.g., posterior orientation of ilia,
long femoral neck, posteriorly directed lesser trochanter,
and severe ‘‘carrying angle’’; see review in Schwartz,
2007a) are present in at least two specimens attributed to
Homo: the subadult KNM-ER 15000 from Nariokotome,
Kenya (cf. Walker and Leakey, 1993; Schwartz, 2007a;)
and a subadult partial skeleton from Dmanisi associated
with skull D2700/D2735 (Lordkipanidze et al., 2007).
The point here is that any endeavor to trace the origin
of H. sapiens directly to H. erectus depends on which
specimens one includes in the latter species, which then
directly affects scenarios of when, where, and, depending
on the degree of speculation, even how H. erectus might
have given rise to H. sapiens. But as already mentioned,
if one diagnoses the species H. erectus on the basis of
derived features preserved in the Trinil specimens [not
only the calvaria (see above) but also the variably com-
plete femora, which are laterally compressed throughout
much of the shaft to a degree typical of tibiae (JHS, per-
sonal observation)], then the hypodigm of the species is
reduced considerably. Indeed, it comprises primarily the
specimens from Sangiran, which, when the petrosal
region is preserved, present the clearly derived configu-
ration of grooves for an arborizing rather than large and
single sigmoid sinus (Schwartz and Tattersall, 2000c,
2003). What makes this latter hypothesis interesting is
that some of the derived features of calvarial morphology
(e.g., the posterior profile of the neurocranium, which is
much wider than high) are also exhibited in Dmanisi
skull D2282, whereas the derived condition of grooves
for an arborizing sigmoidal sinus is present in D2280
(Schwartz and Tattersall, 1999b, 2000c, 2003). How
other specimens that have been allocated to H. erectus
since 1950 may cluster as morphs, and how these
morphs may be related to one another (if indeed they all
are), remains unclear to us, but the hint of a possible
clade of which Trinil and Sangiran H. erectus plus speci-
mens from Dmanisi are a part is neither biologically nor
geographically implausible.
An alternative to the ‘‘H. erectus as ancestor of
H. sapiens’’ notion has been proposed by Bermúdez de
Castro et al. (1997), who have argued that the ancestry
of H. sapiens lies in the species they named H. anteces-
sor from specimens at the ca. 780 ka levels of the Gran
Dolina at Atapuerca, northern Spain. Indeed, one speci-
men, a partially reconstructed subadult skull, and a
zygomatic bone in particular, indicates to them that
H. antecessor gave rise both to H. neanderthalensis and
to H. sapiens. Their argument is that, as in juvenile and
adult H. sapiens, the external infraorbital surface of the
zygoma of their subadult H. antecessor is ‘‘indented’’ or
depressed. However, as in adult H. neanderthalensis, an
adult zygoma (Bermúdez de Castro and Arsuaga, 1999)
from Gran Dolina is not thusly depressed. Bermúdez de
Castro et al. interpret this array of subadult and adult
morphological conditions of the zygoma as indicating
that the indented infraorbital region in adult H. sapiens
represents a neotenic retention during descent from
H. antecessor, whereas the change from subadult to a dif-
ferent adult zygomatic configuration reflects ancestry and
descent between H. antecessor and H. neanderthalensis.
We can certainly agree with Bermúdez de Castro et al.
that H. sapiens and H. neanderthalensis represent dif-
ferent species. For if one interprets the phylogenetic
relevance of Neanderthal morphology in a broader con-
text, and without first imposing on it a scenario of ances-
try and descent, specimens we would call Neanderthal
emerge as unique and distinctive in cranial as well as
postcranial morphology (see reviews in Tattersall and
Schwartz, 1998, 2009; Schwartz and Tattersall, 1999a,
2003, 2006; Schwartz et al., 1999). For example, juvenile
and adult Neanderthals are distinctive in developing a
protruding, wedge-shape ‘‘snout’’ that is puffed out bilat-
erally on its sides because of maxillary sinus expansion
(so much so that the medial orbital wall is typically
involved); a vertically oriented growth of bone (‘‘medial
projection’’) from the lateral wall of the nasal cavity that
projects medially into the nasal cavity; and a well-
defined and pitted suprainiac depression (Fig. 1). In
addition, in frontal view, the adult Neanderthal lower
face tapers medially from the zygomatic arches toward
the alveolar margin, and the occipital bears a partially
delineated nuchal crest, the superior margin of which is
marked only by the superior border of the suprainiac
depression, whereas its inferior ‘‘margin’’ exists because
the nuchal plane undercuts the occipital plane (Fig. 1).
Dentally, the major cusps on all permanent molars and
the deciduous first molars are peripherally placed, thus
opening up basins (trigon and talonid), whereas, in their
lower counterparts, distinct mesial basins are bounded
by thick paracristids and protocristids (Fig. 1). Postcra-
nially, Neanderthal clavicles and pubic rami are rela-
tively the longest among primates, the termini of the dis-
tal row of manual phalanges are broadly rounded (not
tapered) and unusually dorsoventrally compressed, the
groove for the teres minor muscle typically lies dorsally
on the infrascapular border, the pubic symphyseal region
is superoinferiorly tall and thin anteroposteriorly,
and the greater sciatic notch is essentially uniformly
‘‘U’’-shaped.
Yet although it is important to recognize that the
numerous autapomorphies of H. neanderthalensis not
only preclude it from the ancestry of any other known
hominid species, but also presumably from any success-
ful and biologically significant hybridization with them,
it is also necessary to remember that H. sapiens and

H. neanderthalensis were not necessarily the most
closely related of known hominid sister species. Indeed,
if one considers other cranial features that have at one
time or another been put forth as being potentially dis-
tinctive of H. neanderthalensis, such as relatively super-
oinferiorly thick, double-arched brows that are continu-
ous across glabella (Stringer et al., 1984; Stringer and
Andrews, 1988), or a long, horizontally oriented parieto-
mastoid suture (Schwartz and Tattersall, 1996a,b,
1999a), we are obliged to turn rapidly to other non-H.
sapiens specimens in any attempt to discover our closest
relative (Schwartz and Tattersall, 2003).
It may be reasonably argued that Neanderthals are
members of a larger clade (Schwartz and Tattersall,
1996b, 1999a, 2002b, 2003, 2006; Tattersall and
Schwartz, 1998) that also includes the Steinheim skull
and the Sima de los Huesos hominids. Both have some
apomorphies of H. neanderthalensis, but not all.
Embracing this larger clade has nontrivial implications
for the Gran Dolina specimens. For it is at best difficult
to delineate specific features that would unite these
Spanish fossils with the Neanderthal clade, especially
given the marked differences in dental morphology (cf.
Bermúdez de Castro et al., 1997; Bermúdez de Castro
and Arsuaga, 1999; Falguères et al., 1999). Another al-
ternative, no less intriguing, is provided by the detailed
similarities between the lower dentitions of the relevant
Gran Dolina specimens and the teeth that are preserved
in the three mandibles from the penecontemporaneous
Algerian site of Tighenif (Ternifine), originally desig-
nated as H. mauritanicus (cf. Arambourg, 1955; Hublin,
2001; Schwartz and Tattersall, 2003). Although Bermú-
dez de Castro et al. (2007) have pointed to a few differ-
ences between the Gran Dolina and Tighenif specimens
to support retention of the species H. antecessor, this
does not then mean that the original hypothesis ‘‘H.
antecessor is ancestral to both H. neanderthalensis and
H. sapiens’’ is thereby also validated.
If H. antecessor is not a junior synonym of mauritani-
cus, the next most likely hypothesis is that the two taxa
represent closely related species, distinct from those oth-
erwise known in Western Europe. If this hypothesis is
viable, so too is the possibility that the affinities of the
Gran Dolina and Tighenif hominid/s lie closer to H. sapi-
ens than to other hominid species. For, as seen most
clearly in Tighenif 2, the North African specimens bear
a vertical keel along the mandibular symphysis that, in
association with attendant morphologies, is characteris-
tic of H. sapiens (see discussion below and Schwartz and
Tattersall, 2000a, 2003). Because most of the Iberian
Peninsula is climatically and faunally North African
rather than European, it is not surprising that these
seemingly far-flung specimens might represent the same
hominid, or at least a closely related hominid pair. Ques-
tions that remain to be answered, however, include that
of whether either fossil sample represents a population
directly ancestral to H. sapiens, and, thus, which region
represents our geographical site of origin.
With the matter of H. sapiens origins still in limbo,
and if we can exclude as ancestor both H. erectus (how-
ever constituted) and H. neanderthalensis or a member
of its larger clade, and possibly also the Gran Dolina and
Tighenif specimens, a last resort might be the appa-
rently cosmopolitan species H. heidelbergensis. But, as
with H. erectus, this question boils down to how nar-
rowly or broadly one casts the taxonomic net within the
time range of ca. 600–300 ka. For, even though the cra-
nia from Kabwe, Petralona, Bodo, and Arago are fre-
quently presented together or in some combination as
representing H. heidelbergensis (Fig. 2), often forgotten
in this exercise is that the type specimen of this hominid
species is the Mauer mandible (Fig. 3). Consequently if,
and only if, one can demonstrate a connection between
the type specimen and of these or other skulls offered as
heidelbergensis, can we make any case for this taxo-
nomic allocation.
Fortunately, the gracile Arago 13 mandible is suffi-
ciently well preserved to show that, in details of both
teeth and jaw, it shares unique morphologies with the
more massive Mauer mandible (Schwartz and Tattersall,
2002a). Among these are the broad symphyseal region
that arcs superiorly between two well-defined inferior
tubercles, posterior to which the inferior margin of the
corpus is thickened outwardly, creating a distinct some-
what horizontal sulcus above; the huge, low-lying and
posteriorly situated mental foramen; the mandibular
head lying below the level of the tip of the coronoid pro-
cess (which was artificially shorted by animal gnawing);
the very broadly rounded gonial region; the long and
ovoid lower molars, of which M2 is the largest, with long
but buccolingually quite truncated talonid basins; the
hypoconulid that lies in all molars just buccal to the
midline of the crown; the trigonid basin large only in M2
and M3; and the elongate first premolars that taper
mesiodistally whereas the short and rather ovoid second
premolars are wide buccolingually (Schwartz and Tatter-
sall, 2000a, 2002a, 2003) (Fig. 3).
Because it seems clear that the Arago sample repre-
sents one single hominid (Schwartz and Tattersall,
2003), it is reasonable to extend the name heidelbergen-
sis to all these specimens, which include the partial cra-
nium Arago 21. This makes feasible comparison with
specimens known only from crania (Schwartz and Tat-
tersall, 2002a, 2003) (Fig. 2). Particularly compelling in
Arago 21 is the configuration of the brow, which exhibits
an unusual anteroposterior twist of its undifferentiated
anterior surface, and a continuous superior margin that
is defined by a distinct edge or corner (in contrast, for
instance, to the smoothly ‘‘rolled’’ brow of Neanderthals
and Steinheim); because the brow is not markedly pro-
trusive anteriorly and especially superiorly, the post-
toral sulcus behind is rather shallow. Favorable compari-
sons can be made between Arago 21 and cranial speci-
mens from Petralona (Greece), Kabwe (Zambia), Bodo
(Ethiopia), Dali, and Jinniushan (both China). With the
exception of the Jinniushan specimen, the brows of all
these specimens, including Arago 21, are very tall super-
oinferiorly, reaching their maximum height near mid-
orbit.
Still, there are also differences among specimens
within this assemblage (Fig. 2). The nasal bones are
shorter and less protrusive, and the aperture is nar-
rower and situated higher on the face in Arago, Petra-
lona, Kabwe, Dali, and Jinnuishan, than in Bodo.
Although possessing shorter nasal bones than seen in
Bodo, Petralona and, especially, Dali display broad nasal
apertures. In Petralona and Bodo, the lower face is swol-
len infraorbitally and toward the nasal region, whereas
Petralona exhibits much more expansive sinus inflation
than Kabwe does, not only in the face but also superiorly
into the frontal bone. Further, internally, both Arago and
Bodo present a H. sapiens-like configuration involving a
well-excavated hypophyseal fossa that distinctly sepa-
rates a horizontal and long anterior cranial fossa from
101

Fig. 2. Crania from Arago (top left), Bodo (top right), Petralona (bottom left), and Kabwe (bottom right). Note in all superiorly
delineated margins of tall but not necessary anteriorly protrusive supraorbital margins that are essentially flat on their anterior
surfaces, tallest circum-midorbit, and which ‘‘twist’’ superolaterally. Note also, e.g., differences in lower facial expansion or ‘‘puff-
iness’’ and length of nasal bones (and thus expanse of nasal aperture). Not to scale. am. [Color figure can be viewed in the online
issue, which is available at wileyonlinelibrary.com.]
Fig. 1. La Ferrassie 1 cranium (left and middle columns), illustrating cranial features of Neanderthals: e.g., inferomedially
tapering lower face in frontal view; anteriorly protruding, wedge-shape snout; medial projection from lateral wall of nasal cavity;
well-defined and pitted suprainiac depression that is defined below by a partial torus; and undercutting of the occipital by the
nuchal plane. Le Moustier adolescent maxilla (top right) and Krapina 58 mandible (lower right), illustrating typical Neanderthal
dental features: e.g., in the upper molars a large internally situated protocone that truncates the trigon basin and that also expands
the tooth distolingually, peripherally placed protocone and metacone; and in the lower molars a truncated trigonid with distinct par-
acristid that delineates distal to it a mesiodistally thin but buccolingually wide trigonid ‘‘basin’’ (crease, really), peripherally situ-
ated talonid cusps that subtend mesiodistally long and buccolingually broad basins, and round distal ends. Not to scale. [Color fig-
ure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

the middle cranial fossa. In contrast, Kabwe and Petra-
lona are similar to various australopiths as well as to
apes and other anthropoids in that the anterior cranial
fossa is virtually in the same plane as the obliquely ori-
ented clivus, with a shallow and ill-defined hypophyseal
fossa that barely distinguishes the two intracranial
regions (Seidler et al., 1997; Schwartz and Tattersall,
2002a). Whether this similarity reflects primitive reten-
tion or secondary derivedness awaits further study.
Clearly, however, even though specimens referred to
H. heidelbergensis would seem to be strongly united on
the basis of their derived supraorbital morphology, it is
also evident (especially on the basis of intracranial mor-
phology) that this species subsumes a substantial mor-
phological variety, possibly even suggesting the presence
of more than one hominid morph. On the reasonable
assumption that all specimens in this group are at least
closely related, one might suggest a relationship of this
potential H. heidelbergensis clade with the Neanderthal
clade, but aside from presenting a brow that is thickened
superoinferiorly to some extent (a descriptor that can be
applied to a number of other hominids), we are hard put
to delineate specific morphologies that support this hy-
pothesis. More importantly, the same suite of apomor-
phies that distinguishes the ‘‘heidelbergensis’’ group
would certainly also preclude any of its members from
being ancestral to H. sapiens and would likely exclude
all from a clade that included the latter.
PRESUMED EARLY H. SAPIENS
The notion that an archaic phase of H. sapiens
emerged from H. erectus, subsequently transitioning into
‘‘early anatomically modern’’ H. sapiens and then into
‘‘recent anatomically modern’’ H. sapiens, has occupied
reams of text over decades. Frequently, still included in
the archaic phase of this continually changing lineage-
species H. sapiens are the specimens just discussed from
Arago, Petralona, Kabwe, Bodo, Saldhana, Singa, Jin-
niushan, and Dali. Because the conception of archaic
and ‘‘modern’’ phases of a single species is unusual in pa-
leontology, even when ‘‘species’’ is taken as equivalent to
‘‘lineage’’ (should we actually be entertaining notions of
archaic versus anatomically modern Tyrannosaurus rex,
Plesiadapis tricuspidens, Omomys carteri, or Proconsul
africanus?), its anomalous persistence in paleoanthropol-
ogy most likely reflects the unusual history of the latter,
dominated from the beginning by transformationist
notions (e.g., Huxley, 1863; Mayr, 1950; Dobzhansky,
1955, 1962). Yet, clearly the persistence of this tradition
does not do justice to what has in recent years become a
vastly better-known human fossil record, the analysis
and systematic interpretation of which should be based
on the available morphological evidence, not a priori on
debatable phylogenetic scenarios.
The first proposed evidence of a morphological transi-
tion from archaic to anatomically modern H. sapiens
came from specimens recovered from the Levantine sites
of Tabūn and Skhūl (McCown and Keith, 1939).
Although McCown and Keith originally grouped the
Tabūn and Skhūl hominids together as members of a
highly variable but distinct species, Palaeoanthropus
palestinensis, the placing of these specimens in a precon-
ceived morphological continuum from ‘‘more archaic’’ to
‘‘more fully modern’’ H. sapiens has persisted in the lit-
erature, with the Tabūn material (possibly 122 6 16 ka)
often being regarded as more morphologically Neander-
thal and the Skhūl specimens (stage 5, ca. 119 ka) as
overall more anatomically modern (e.g., Howell, 1958;
Stringer, 1978).
Two partial crania from the Omo Kibish Formation,
Ethiopia [Omo I and Omo II, both now believed to be ca.
195 ka (McDougall et al., 2005)], were originally
described by Day (1969), who regarded them both as var-
iants of H. sapiens while admitting that Omo I was more
modern in cranial shape and Omo II more archaic. On
reconstructing the Omo I specimen, Day and Stringer
(1982) aligned Omo I with H. sapiens and Omo II with
H. erectus, but they later emphasized the dissimilarities
between the former and other specimens allocated to H.
sapiens (Day and Stringer, 1991).
Particularly following their description by Vander-
meersch (1981), specimens excavated from another Le-
vantine site, Jebel Qafzeh (early stage 5, probably
between 100 and 90 ka), have typically been viewed as
representing a single population that was almost, if not
fully, anatomically modern (Howells, 1974; Stringer,
1974; Vandermeersch, 1981; Trinkaus, 1984). Also from
the Levant, the Zuttiyeh (Galilee) frontal (possibly 2001
ka), which Keith (1927) suggested was morphologically
Neanderthal-like, has subsequently been promoted as
‘‘archaic H. sapiens’’ (Vandermeersch, 1982) and as an-
cestral to a Qafzeh/Skhūl group (Wolpoff, 1989a) or even,
by association with Skhūl V, as modern human (Zeitoun,
2001).
Singer and Wymer (Singer, 1953) described all of the
material from Klasies River Mouth, South Africa
(ranging from perhaps as old as 120 ka to ca. 60 ka,
with the majority dated to at least 80 ka), as completely
anatomically modern H. sapiens. Many paleoanthropolo-
gists continue to reiterate this conclusion, although
others have challenged it (e.g., Wolpoff et al., 1994a).
From our study of the Klasies River Mouth material, we
concluded that two morphs were actually represented in
the sample (Schwartz and Tattersall, 2000a).
The most recent discoveries attributed to early ana-
tomically modern H. sapiens were found at Herto, Mid-
dle Awash, Ethiopia, and date to 154–160 ka (White et
al., 2003). Of the three adult crania, only one (BOU-VP-
16/1) was sufficiently complete to allow White et al. to
present systematically useful morphology. Although they
described the supraorbital region of this specimen as bi-
partite, they based their suggestion that the Herto adult
is more modern than archaic on metrical comparisons
with African fossils they accepted as representing both
H. erectus and archaic H. sapiens, plus non-African mod-
ern humans and various Neanderthal specimens. The
reconstructed partial skull of a child (BOU-VP-16/5, esti-
mated to have been 6–7 years at death), found in frag-
ments on the surface, was interpreted via craniometric
analysis as similar to the adults from Herto, basically in
not presenting an (unspecified) Neanderthal complex of
features. Also central to the describers’ conclusion was
Herto’s chronological intermediacy between older, ar-
chaic H. sapiens African sites and specimens from
younger Late Pleistocene sites.
The absence of morphological detail in this brief over-
view of specimens attributed to H. sapiens once again
reflects the peculiar history of paleoanthropology, in
which chronology, not morphology, is typically regarded
as the crucial determinant. In terms of morphology,
what we glean is a general understanding that, at least
craniodentally, any specimen classified as anatomically
modern should be relatively thin-boned and small-
103

toothed. It should have a neurocranium that is relatively
vaulted (in frontal and lateral view), tall and parallel-
sided (in rear view), and not too elongate (in profile) as
well as a relatively small face (and a ‘‘reduced’’ brow), a
maxillary incisura (canine fossa), a non-torus bearing
occipital, and poorly developed muscle scars (particularly
from the temporal muscles, whose lines should lie low on
the parietals). In addition, the mandible should be small,
gracile, and weakly muscle-scarred and should bear a
swelling in the symphyseal region.
But although this description might seem on the face
of it sufficient, it really does not approach the level of
detail routinely demanded in systematic studies of other
organisms. This is hugely to the detriment of our knowl-
edge of the origin of H. sapiens, and it is not a situation
that will be rectified easily or quickly. Nonetheless, we
can offer a few suggestions.
TOWARD AN UNDERSTANDING OF H. SAPIENS
MORPHOLOGY: TWO DEVELOPMENTAL
EXAMPLES
Although we are still far from understanding the
details of developmentally regulated genes and signal
transduction pathways, or even the effects of hyper- ver-
sus hypoexpression of transcription factors on the devel-
opment of morphology (which is all we have for fossils),
the existence of a continuum from the molecular to the
morphological is now well documented (e.g., Gerhart and
Kirschner, 1997; Ronshaugen et al., 2002; Davidson and
Erwin, 2006; Newman, 2006; Stern et al., 2006). It thus
follows that any ontogenetic information should be
explored because it reflects some aspect of this contin-
uum in the emergence of final form. Here, we review the
evidence relating to the development of the supraorbital
and symphyseal regions as examples of this perspective
and its relevance to understanding the unique morphol-
ogy of H. sapiens.
The supraorbital region
A broad survey of anthropoid primates reveals that,
regardless of the specific morphology of the adult supra-
orbital region, in very young individuals (i.e., even as
late as M1 eruption) the generally smooth supraorbital
region invariably gives little or no hint of the morphol-
ogy that will eventually characterize the adults (dimor-
phic or otherwise) of that species (Schwartz, 1997 and
unpublished data). Indeed, it is virtually impossible to
predict from the neonate what its adult supraorbital
morphology will be.
Adult conformations of this region vary widely. In
papionins (see Schwartz, 1997), the adult supraorbital
region presents a distinctly defined, superoinferiorly
thin, and anteriorly projecting bar-like torus that runs
essentially straight across from side to side. In African
apes (Pan troglodytes, P. paniscus, and Gorilla spp.), the
supraorbital region grows into an anteroposteriorly thick
torus, with a markedly vertical component that produces
a post-toral sulcus behind and which is indented over
glabella to varying degrees (Fig. 4). The list of examples
is endless, but from the undistinguished supraorbital
region of the juvenile, myriad distinctive adult configura-
tions emerge developmentally, ranging from the projec-
ting, ‘‘goggle-like’’ circumorbital region of gibbons and
siamangs, through the superomedially- and laterally
raised partial circumorbital rims of Pongo, to the more
fully but differently rimmed orbits of various New World
monkeys, such as Cebus and Alouatta (Schwartz, 1997).
Even though one might expect living H. sapiens, the
poster-child of paedomorphosis, to be the most neotenic
of anthropoids in supraorbital morphology, it is not.
Rather, one also finds little or no supraorbital embellish-
ment not only in the small marmosets and tamarins, but
also in various colobine monkeys (thereby ruling out size
as a factor in lack of supraorbital morphology). Still, in
H. sapiens, albeit closer to the onset of adulthood than
in other anthropoids, the previously featureless region of
glabella (Fig. 4; also Fig. 12) swells anteriorly (even if
only slightly), and from each side of this mounded mid-
line a wing-like swelling may also emerge, its inferolat-
eral extremity terminating generally at the supraorbital
foramen/notch (i.e., near the midpoint of the superciliary
arch) and the superolateral extremity extending some-
what beyond this point laterally (Fig. 4). Altogether, this
mounded protrusion forms a ‘‘butterfly’’-like shape,
which elsewhere we have described as a ‘‘glabellar but-
terfly’’ (e.g., Schwartz and Tattersall, 1996b, 1999a,
2002b; Tattersall and Schwartz, 1998; Antunes et al.,
2000). On each side, the superciliary region lateral to
the ‘‘butterfly wing’’ is flatter and more plate-like, with
perhaps also a slight posterior declination to its surface
(Fig. 4). This then constitutes the ‘‘bipartite’’ brow, the
development of which is unique to H. sapiens compared
with all living and almost all fossil primates.
Among fossil hominids, the available sample is
adequate to allow us to track the emergence of the thick,
double-arched, and laterally continuous brow seen in H.
neanderthalensis (Schwartz and Tattersall, 1996b,
2002b, 2003). As in extant anthropoids, the supraorbital
region of 3–4-year-old specimens (Engis, Pech de l’Azé,
Roc de Marsal, and Subalyuk) is featureless in this spe-
cies (Fig. 5). Only in slightly older individuals (La Quina
child and Teshik Tash) can one discern with any confi-
dence the beginning of supraorbital swelling, which
developmentally expands bilaterally from the region of
glabella (Fig. 5). In the Le Moustier adolescent, the lat-
erally continuous brow typical of Neanderthal adults can
already be detected (Fig. 5). What cannot be known,
though, is whether the brow of this individual would
have become much more anteriorly distended as it
matured, as in La Ferrassie I and especially Guattari, or
if it would have remained relatively low as in Gibraltar I
or Krapina C (Skull 3) (Fig. 5).
Nevertheless, what is important about these speci-
mens is that they are consistent with a picture of
taxon-specific, postnatally achieved, supraorbital mor-
phology. Consequently, although we cannot reliably
infer adult supraorbital form from the study of juvenile
hominids, such as those from Herto, Modjokerto, Taung,
Skhūl I, and Dikika, we can state with some confidence
that the specific supraorbital morphology of any adult
was acquired during growth from a previously feature-
less frontal bone. With this in mind, we turn to fossil
specimens that have been considered anatomically mod-
ern H. sapiens, in search of those that present a bipar-
tite brow.
Among the fossils that most of us were taught were
uncontestable early representatives of our species are
specimens from Qafzeh and Skhūl. From Qafzeh, the
specimen most frequently cited and illustrated is the
fairly complete skull Qafzeh 6. Yet this specimen lacks a
bipartite brow, possessing instead a superoinferiorly
somewhat tall brow that is anteriorly low and mounded,

Fig. 4. Emergence of supraorbital morphology in Gorilla, from the nondescript to the specific (counterclockwise, from top left to
top right), and in H. sapiens (right column), from 7 month fetus to adult (in the adult, arrows point to the medial ‘‘glabellar butter-
fly,’’ which, in this specimen, extends into the field of the laterally flatter plane). Not to scale. [Color figure can be viewed in the
online issue, which is available at wileyonlinelibrary.com.]
Fig. 3. Comparison of Mauer (left column) and Arago 13 (right column) mandibles. Although the former is larger and more ro-
bust, both are uniquely similar in possessing: low and vaguely defined articular condyles; sigmoid notch crests that are deepest
below the condyles; broadly arcuate but also posteriorly truncated gonial regions; posteriorly situated large mental foramina that
lie at the termini of laterally thickened corporal tori; lateral corpora tori that delineate below them an anteroposteriorly long sulcus
that is defined below by a thickly everted inferior corporal margin; and an inferior corporal margin that terminates in an inferior
marginal thickening that serves as the ‘‘tethering point’’ of a upwardly arcing inferior margin that ‘‘lifts’’ the lower margin of the
anterior surfaces upward. Note also similar disparity in morphology between P1 and P2 and rounded mesial and especially distal
ends of elongate molars that bear buccally situated hypoconulids and filled-in, crease-like talonid basins. Not to scale. [Color figure
can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

and continuous across an equally tall glabellar, region.
Thus, although the neurocranium of Qazeh 6 is rather
globular, and relative to it the face is not massive, this
specimen conspicuously lacks the one particular apomor-
phy that would cement its allocation to H. sapiens
(Schwartz and Tattersall, 1996b, 2000b) (Fig. 6).
Less frequently discussed and illustrated are the bro-
ken, but reasonably reconstructed, adult Qafzeh 9 and
the less complete and subadult Qafzeh 11 crania (Fig. 6).
Yet for our discussion here, these specimens are interest-
ing and frustrating in equal measure. The adult Qafzeh
9 specimen is so damaged that we can only surmise that
the fragment that is apparently correctly placed medially
in the superciliary arch on the left side is mounded or
somewhat swollen, suggesting the ‘‘butterfly’’ configura-
tion. Bone laterally in both superciliary regions is more
clearly flat and plate-like, also suggesting that Qafzeh 9
possessed a bipartite brow. Although the subadult Qaf-
zeh 11 is less damaged, and thus presents a more pris-
tine supraorbital region than Qafzeh 9, crucial morpho-
logical detail in this region was not yet fully developed.
Nevertheless, we feel confident in identifying the glabel-
lar ‘‘butterfly-shape’’ swelling characteristic of a bipartite
brow.
Along with Qafzeh 6, Skhūl V has often been pre-
sented as a representative of ‘‘early anatomically mod-
ern’’ H. sapiens (Fig. 7). Like Qafzeh 6, the skull is gen-
erally rounded and vaulted in profile, and the largely
reconstructed face does not present itself as excessively
massive relative to the neurocranium. Also as in Qafzeh
6, what is preserved of the supraorbital region of Skhūl
V does not present a bipartite configuration. Interest-
ingly, the brow of Skhūl V is less tall superoinferiorly,
and much more anteriorly protrusive in the form of a
torus, than its counterpart in Qafzeh 6 (Fig. 7). The
Skhūl II frontal fragment (which retains the glabellar
region together with some of the left supraorbital
region and most of the right) and the small portion of
the left supraorbital region of Skhūl IV are strikingly
similar to Skhūl V (Fig. 7). However, in Skhūl IX, the
preserved right supraorbital region, with most of gla-
bella, is superoinferiorly thin but arced rather than rel-
atively straight, and barely protrudies anteriorly (Fig.
7). Skhūl VII retains the lateral portion of the right or-
bital region, but the anterior surface of the superciliary
arch is missing; the brow appears to have been arcuate
and may have been taller than in the other Skhūl speci-
mens. Predictably, the supraorbital region of the juve-
nile cranium Skhūl I is featureless. Thus, whatever the
exact morphology of each of the Skhūl specimens, there
is no trace of a glabellar ‘‘butterfly’’ in any of them.
With regard to other specimens that have been identi-
fied as ‘‘early anatomically modern’’ H. sapiens, we could
confidently detect a glabellar butterfly only in the Liu-
jiang cranium ([67 ka, possibly 101–227 ka) (Fig. 7). In
the otherwise distinctive LH 18 (Ngaloba) calotte (108–
129 ka) (Fig. 7), there appears to be something resem-
bling this structure, the more robust and superoinfer-
iorly thicker lateral portion forming an antero-obliquely
facing plane (Schwartz and Tattersall, 2003). The varia-
bly complete crania of Omo Kibish I and II, Singa, and
Jebel Irhoud I, and the Klasies River Mouth frontal frag-
ment (Figs. 8 and 9), are broadly contemporaneous with,
or older than, the Liujiang and LH 18 specimens and
have been suggested as at least representing a precursor
to anatomically modern H. sapiens. None of these speci-
mens, however, displays a supraorbital configuration
that could be described as bipartite, or as possessing a
butterfly-shaped glabellar region.
We have not been able to examine the adult cranial
specimen (BOU-VP-16/1) from the somewhat older site of
Herto, Middle Awash. However, we need to mention it
because it has been allocated not only to H. sapiens, but
also to a new subspecies, H. sapiens idaltu (White et al.,
2003). As is clear from the excellent published images,
BOU-VP-16/1 has a more robust and superoinferiorly
taller brow (including the lateralmost extremity) than
any fossil in which we can confidently describe a bipar-
tite brow replete with glabellar ‘‘butterfly.’’ As seen in
the published photographs, the more completely pre-
served right superciliary arch of BOU-VP-16/1 presents
a slightly postero-obliquely oriented ‘‘crease’’ that delin-
eates medial and posterior moieties, with the medial por-
tion more anteriorly facing and the posterior portion
inclining posteriorly. Atypical of any bipartite brow, how-
ever, is that the anterior surface of the medial supraorbi-
tal moiety of BOU-VP-16/1 is vertically flat from top to
bottom and appears to ‘‘twist’’ toward its medial extrem-
ity so that it ultimately faces rather laterally. The supe-
rior margin of this anterior moiety also bears a distinct
margin that continues onto the glabellar region, thus
partitioning the two supraorbital sections as separate
entities.
Among chronologically younger specimens that have
been considered definitively anatomically modern H.
sapiens are the incomplete crania Border Cave 1 and
Dar es Soltane II (Fig. 9). Although we have in the past
agreed with this interpretation (Schwartz and Tatter-
sall, 2003), our reassessment of these specimens has
made us much more tentative now in both cases.
Among the variably complete Pleistocene crania that
we also viewed as morphological H. sapiens in our 2003
study, we still confidently include in our species the rel-
atively recent specimens from Abri Pataud, Brno, Chan-
celade, Combe Capelle, Cro-Magnon, Dolni Věstonice,
Engis (the adult), Grimaldi, Isturitz, Mladeč, Pavlov,
Predmostı́, Svitavka, Tuinplaas, Velika Pécina, Vogel-
herd, Wajak, Zhoukoudian Upper Cave, and Zláty Kůn
(Fig. 10). Unaligned with typical H. sapiens on supraor-
bital conformation are the very recent specimens from
Fish Hoek and Boskop (Schwartz and Tattersall, 2003)
(Fig. 11). The latest estimate of 6891 6 37 BP for Fish
Hoek (Stynder et al., 2009) makes this atypicality all
the more intriguing.
The ‘‘chin’’
From at least the time of Blumenbach’s (1969) treatise
on features that distinguish H. sapiens from other living
animals, the human ‘‘chin’’ has received particular atten-
tion from comparative biologists (Schwartz and Tattersall,
2000a). Unfortunately, the focus has typically been on the
presence of some (any) anterior protrusion in the region
of the mandibular symphysis. This has led to such
unhelpful comments as that the only living mammals
that develop a chin are humans and elephants (Enlow,
1982). In the search for evidence of the emergence of ana-
tomically modern from more archaic H. sapiens, any
three-dimensional perturbation of a symphyseal surface
that in other mammals is typically smooth or flat
(whether vertical or posteroinferiorly slanted) tends to be
taken as evidence of an incipient chin. In light of this em-
phasis on simple anterior protrusion, rather than on mor-
phological detail, even modern-day humans who fail to

achieve the requisite anterior growth of the mandible
have been seen as anatomical curiosities (Enlow, 1982).
Nevertheless, although the form and development of the
feature that is truly unique to H. sapiens, the chin, has
been illustrated and described in textbooks for centuries,
its systematic and phylogenetic significance has been
obscured by the endeavor to create a sequence of morpho-
logical transformations from extinct to extant humans.
Fig. 6. Comparison of Qafzeh 9 (left column), Qafzeh 11 (middle column), and Qafzeh 6 (right column). The former two speci-
mens appear to have had a bipartite brow, which is clearly lacking in Qafzeh 6. See text for detail. Not to scale. [Color figure can be
viewed in the online issue, which is available at wileyonlinelibrary.com.]
Fig. 5. Growth sequence demonstrating emergence of the ‘‘double arched’’ and smoothly rolled supraorbital region typical of
adult Neanderthals (La Quina child, top left; Teshik Tash juvenile, bottom left; Le Moustier adolescent, top right; and Krapina C
(skull 3), bottom right). Not to scale. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]
107

Fig. 8. Comparison of Omo Kibish I [left and middle columns; frontal, mandible (anterior, right profile, inferior views), and lat-
eral view of occipitoparietal region] and Omo Kibish II (anterior and right lateral cranial views, right column). The two may repre-
sent different morphs, but they are similar in lacking a bipartite brow. The symphyseal region of Omo Kibish 1 clearly lacks
H. sapiens’s features. See text for detail. Not to scale. [Color figure can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
Fig. 7. Comparison of Skhūl V, Skhūl IX, and Qafzeh 6 (top, left to right), and LH18 (Ngaloba), Skhūl II (lower middle, anterior
and oblique views), and Liujiang (bottom, left to right). Although the superciliary region in Skhūl V is the most protrusive anteri-
orly (followed by Skhūl II) and is the least tall superoinferiorly, neither it nor the other specimens present a bipartite brow. The
‘‘crease’’ in the right supraorbital region of Skhūl V is due to damage. Note also the distinctly teardrop-shaped bulge, rather than
inverted T-shape of the H. sapiens ‘‘chin.’’ See text for detail. Not to scale. [Color figure can be viewed in the online issue, which is
available at wileyonlinelibrary.com.]

Fig. 9. Variably complete crania of Jebel Irhoud 1 (top left), Dar es Soltane II (bottom left), Border Cave 1 (top right), Singa
(bottom right), and Klasies River Mouth frontal 6103 (middle). None displays evidence of a bipartite brow. Not to scale. [Color figure
can be viewed in the online issue, which is available at wileyonlinelibrary.com.]
Fig. 10. Crania and associated mandibles of various fossil H. sapiens: Abri Pataud, Mladeč 1, and Dolni Věstonice XV (top, left
to right); Grimaldi 5, Cro-Magnon 2, and Wadjak 4 frontal and Wadjak 23 mandible (bottom, left to right). Note variable expression
both of a bipartite supraorbital configuration and of an inverted T-shaped chin. Not to scale. [Color figure can be viewed in the
online issue, which is available at wileyonlinelibrary.com.]
109

As reviewed elsewhere (Schwartz and Tattersall,
2000a; Schwartz, 2007b), the major features of the
human chin are visible prior to the fifth fetal month,
well before the right and left sides of the mandible fuse
along the symphysis (Fig. 12). Specifically, early on,
there is an anteriorly raised inferior symphyseal margin
that continues laterally for some distance, creating the
depression that in adults is identified as a mental fossa.
Before birth, and continuing afterward until coalescence
is complete, the right and left raised symphyseal mar-
gins fuse from top to bottom (Fig. 12). The result is an
inverted ‘‘T’’ configuration in which the stem of the ‘‘T’’
is represented by the raised but now joined right and
left symphyseal margins, and the arms on either side of
the fused symphysis are the thickened inferior margins.
The mental fossae lie on either side of the stem of the
inverted ‘‘T’’ and above the thickened inferior margin.
With continued growth and bone remodeling, and the
emergence of the first set of anterior teeth, the mandibu-
lar alveolar margin grows superiorly away from the tip
of the stem of the inverted ‘‘T.’’ The crisp and thin rami
of the inverted ‘‘T’’ also thicken, especially along the in-
ferior margin and at the juncture of the stem and the
arms, forming what in the adult is commonly identified
as a ‘‘mental trigon’’ (Fig. 12). Sometimes the lateral
extremities of the arms also thicken and are then
referred to as mental tubercles. Although the superior
limit of the stem often becomes less distinct, it never
extends to the alveolar rim because its development is
from the basilar, Meckel’s cartilage-derived bone of the
mandible, whereas alveolar bone derives from the neural
crest-derived mesenchymal cells that give rise to the
teeth and their attendant soft and hard tissue structures
(Ten Cate and Mills, 1972). Of further note in H. sapiens
is that, from the juvenile through the adult, the symphy-
seal region is noticeably thicker anteroposteriorly than
the bone of the corpora on either side when viewed from
below (Fig. 12). Thus, in H. sapiens, the anterior region
of the mandible differentiates early on in fetal develop-
ment into the basic configuration that will be retained to
varying degrees of crispness in the adult.
In anthropoid primates, the anterior region of the neo-
nate mandible is essentially as featureless as it will
remain in the adult (Schwartz, 1997, 2007b; Schwartz
and Tattersall, 2000a). Indeed, as seen for instance in
the Taung child and Swartkrans SK 3978, the feature-
less symphyseal region is consistent with the equally
featureless symphyseal regions of australopith adults,
regardless of the morph they represent (Fig. 13). Conse-
quently, it is reasonable to conclude that if the adults of
a species present a morphologically blank symphyseal
region, the juveniles did too.
Although some adult Neanderthal specimens may ex-
hibit some anterior symphyseal topography, it is signifi-
cantly absent in both the Le Moustier adolescent and
known juveniles, Gibraltar 2 (Devil’s Tower), Pech de
l’Azé, Roc de Marsal, Amud, and Teshik Tash (Schwartz
and Tattersall, 2002b, 2003) (Fig. 14). Indeed, the verti-
cally oriented symphyseal regions of these specimens are
similarly broad and shallowly curved from side to side,
with a smooth profile across the midline. This configura-
tion is retained in a number of adults, notably La Fer-
rassie I, La Chapelle-aux-Saints, and various mandibles
from Krapina. But in other adult specimens, the midline
in lateral profile may slope down and back (e.g., Tabūn
C1); the anterior teeth may protrude anteriorly farther
than the bone below (e.g., some Krapina specimens); or a
subincisal fossa may produce apparently protruding an-
terior teeth and, immediately below (but well above the
inferior margin), a gentle bulge or swelling (e.g., Spy 1,
Shanidar 1) (Fig. 14) (also illustrations in Schwartz and
Tattersall, 2002b). Also of note, from juvenile into adult,
is that when viewed from below the Neanderthal sym-
physeal region not only is broad and variably straight
across or shallowly arced from side to side, but is also
typically (though not invariably, in Regourdou and
Kebara, for example, bone thickness is consistent) thin-
ner anteroposteriorly than the bone of the corpora on ei-
ther side (Fig. 14). In any event, from a developmental
perspective, the variability in details of adult Neander-
thal symphyseal configuration clearly emerged with
growth from a morphologically undistinguished symphy-
seal surface. Thus, no Neanderthal adult specimen with
a bulge (invariably well above the inferior margin) pro-
vides any insight into the ‘‘evolution’’ of the human chin.
Given the obvious differences between H. sapiens and
Neanderthals, the mandible of the Skhūl I child is of
particular interest (Figs. 14 and 15). For, although par-
tially reconstructed in the symphyseal region, the pre-
served bone on the inner surface demonstrates that it
was very broad and gently arced from side to side; it was
also thin anteroposteriorly and thicker farther along the
corpora. Although not extending across the midline, the
bone preserved externally on the right side is smooth
and shows no sign either of a mental fossa or of a rise to-
ward the symphysis. In addition to this atypical (for
H. sapiens) symphyseal morphology, the exposed right
M1 presents not only the peripherally placed cusps and
broad and long talonid basin characteristic of Neander-
thals, but also a well-developed centroconid, as in the
Tabūn C1 M1 (Schwartz and Tattersall, 2003) (Fig. 14).
These comparisons are particularly interesting in light
of the fact that, even though slightly distorted, the out-
line of the cranial vault viewed from behind and the
morphological details of the occipital region are not typi-
cal of Neanderthals, as is also the case with the adult
specimen Skhūl V.
With regard to the Skhūl adults, the Skhūl V mandi-
ble (Fig. 16; also Fig. 7) is damaged along the incisor
roots, but the reconstruction of these teeth as slightly
anteriorly inclined, and of the subincisal fossa immedi-
ately below, seems to be accurate. In profile, an anterior
bulge emerges below the subincisal fossa, reaching its
most anterior extent around the inferior margin. In front
view, this bulge is teardrop-shaped, and it transitions
smoothly into the surrounding bone all around it
(Schwartz and Tattersall, 2000a, 2003). In inferior view,
the Skhūl V mandible is clearly uniformly thick antero-
posteriorly throughout the broad symphyseal region,
becoming somewhat thicker more laterally along the cor-
pora.
The less well-preserved Skhūl IV mandible is broken
between the right C1 and P1, but the intact symphyseal
region shows the same curvature and anteroposteriorly
uniform thickness as Skhūl V (Fig. 16). In Skhūl IV, the
anterior teeth are not truly forwardly inclined, but are
instead undercut by an extremely shallow subincisal
fossa below which, in left profile, a bulge not unlike that
in Skhūl V emerges. In anterior view, some damage not-
withstanding, the bulge is broader than in Skhūl V and
less well defined, but it too merges smoothly with the
surrounding bone. Only the anterior portion of the man-
dible of Skhūl II (Fig. 16) is known (better along the
right corpus than the left), but the relative uniformity of

Fig. 11. Boskop (left column, including left partial mandible in symphyseal, left lateral, and inferior views, and Fish Hoek
(middle and right columns). Note nonbipartite supraorbital configuration. Note in anterior and lateral views of the mandible
the smoothness of the symphyseal region and, in inferior view, the relatively uniform anteroposterior thickness of the bone
from the symphyseal region onto the corpus. Not to scale. [Color figure can be viewed in the online issue, which is available at
wileyonlinelibrary.com.]
Fig. 12. Growth series illustrating the configuration of the symphyseal region in H. sapiens. Five-month fetus (upper left): note
everted symphyseal and inferior margins and large and deep bilateral mental foramina; also, the symphyseal sides have only begun
to fuse superiorly, a process that will continue inferiorly. Two- to 3-year old (bottom left): anteriorly, note everted inferior margins
with mental fossae above and in the midline a modest triangular swelling of bone; inferiorly, note that the symphyseal region is
thicker anteroposteriorly than the corpora immediately lateral to it. In the 5-year-old (middle) and adult (Abri Pataud) (right), note
that that the thickness is maintained inferiorly, whereas, in the symphyseal regions, the inverted T is variably expressed. Pre-adult
specimens are in uncatalogued teaching collections, American Museum of Natural History. Not to scale. [Color figure can be viewed
in the online issue, which is available at wileyonlinelibrary.com.]
111

anteroposterior thickness throughout this region is pre-
served. Unfortunately, plaster reconstruction occupies
much of the upper portion of the anterior surface of the
symphyseal region, but it is clear, as seen particularly
on the right side, that the surface between the mental
foramen and the front of the jaw is not hollowed out or
Fig. 13. Anterior views of mandibles of young and adult australopiths illustrating their characteristically featureless symphy-
seal regions. Taung child, Swartkrans SK3978 child, and Makapansgat MLD 2 subadult (top, left to right); Swartkrans SKW 5,
Peninj, and SK 12 (bottom, left to right). Note also, as in juvenile anthropoids generally, the supraorbital region of Taung is essen-
tially featureless. Not to scale. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]
Fig. 14. Growth series from Neanderthal children to adult in anterior and inferior views to illustrate characteristic symphyseal
configuration. Amud infant, Pech de l’Azé child, and Le Moustier adolescent (top, left to right); Krapina 58 and La Ferrassie 1
adults (bottom, left and right). Note variability in anterior ‘‘overhang’’ of anterior teeth versus smooth surface in adults; note inferi-
orly, especially in pre-adults, that the symphyseal region may be thinner anteroposteriorly than the bone of the corpora to either
side. See text for detail. Not to scale. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]

Fig. 15. Partial skull and mandible of Skhūl I child compared with inferior view of mandible of Tabūn C1 (lowermost right) and
close-up of Tabūn C1’s left M1 (insert with mandible of Skhūl I). The numerous views of the Skhūl I mandible demonstrate that
reconstructed Neanderthal-like shape of the symphyseal region and its thinness anteroposteriorly relative to the thicker corpora is
accurate. Also note evidence of a centroconid in the Tabūn C1 molar, which is pronounced in the Skhūl I child. Note also in Skhūl
I, as in all juvenile anthropoids, the featureless supraorbital region. Not to scale. [Color ﬁgure can be viewed in the online issue,
which is available at wileyonlinelibrary.com.]
Fig. 16. Skhūl IV, II, and V (top, left to right) and Border Caves 2 and 5 (bottom, left and right). Note variably developed tear-
drop-shaped bulge in symphyseal region of Skhūl specimens and anteroposteriorly uniformly thick bone from symphyseal region
onto corpus in all. The symphyseal region of Border Cave 5 is essentially featureless, whereas that of BC 2 is enigmatic in present-
ing a bulge versus a developmental derivative of an inverted T. Not to scale. [Color ﬁgure can be viewed in the online issue, which
is available at wileyonlinelibrary.com.]
113

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