AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 83~137-146 (1990)

A Reappraisal of the Anatomical Basis for Speech in Middle Palaeoli t h ic Homi n ids

B. ARENSBURG, L.A. SCHEPARTZ, A.M. TILLIER, B. VANDER- MEERSCH, AND Y. RAK Department of Anatomy and Anthropology, Sackler Medical School, Tel Aviu University, Tel Aviv 69978, Israel [B.A., Y.R.1; Department of Sociology and Anthropology, Moorhead State University, Moorhead, Minnesota 56560 (L.A.S.1; U A 376 C.N.R.S., Lahoratoire d‘Anthropologie, Uniuersite de Bordeaux, 33405 Tulence, France (A.M.T., B.V.I

KEY WORDS Evolution vf speech, Hyoid hone. Vocal tract

ABSTRACT The recovery of a fossil hominid skeleton with a complete hyoid bone from Mousterian deposits in Kebara Cave, Israel, provides new evidence pertaining to the evolution of speech. Previous studies of speech in the Middle Palaeolithic (most notably those on Neandertals) have focused on the basicranium as an indicator of speech capabilities. This work critiques the use of the basicranium and instead presents the anatomical relations of the hyoid and adjacent structures in living humans as a basis for understanding the form of the vocal tract. The size and morphology of the hyoid from Kebara and its relations to other anatomical components are almost identical to those in modern humans, suggesting that Middle Palaeolithic populations were anatomically capable of fully modern speech.

During recent archaeological excavations in the Mousterian layers (dated to ca. 60.000 B.P.; Valladas et al., 1987) of the Kebara Cave, Mount Carmel, Israel, a human male skeleton, Kebara 2’ (minus cranium), was found, which included a complete hyoid bone (Bar-Yosef et al., 1986). The latter find is of special importance because it is the first hyoid bone of any fossil hominid ever discov- ered. The Kebara 2 hyoid fills a large gap in our knowledge of early human respiratory and vocal tracts; prior to this discovery, “bony landmarks such as the hyoid bone or styloid rocess which give clues to the posi-

tures, are . . . often missing. hus, the con- figuration of the upper respiratory system of fossil hominids has remained a mystery” (Laitman et al., 1979:15).

METHODS Anatomical relationships and positioning

of the hyoid bone and larynx The larynx, mandible,’ hyoid bone, styloid

processes and other related structures form the visceral skeleton and are derived from the embryonic pharyngeal arches. The man- dible is the only osseous element of this

?r tion an pd shape of upper res iratory struc-

related osteochondral skeleton generally preserved among the remains of ancient or even recent humans. The distal segment of the styloid rocess is rarely preserved, and

been reported for prehistoric hominids. Par- enthetically, it may be mentioned that func- tionally different com onents of this same

dle ear. Some of these tiny bones are known from Mousterian remains (Angel, 1972; Arensburg and Nathan, 1972; Arensburg

indeed the K yoid bone has heretofore never

visceral skeleton are t R e ossicles of the mid-

Received February 23,1989; accepted January 15,1990. ‘The Middle Palaeolithic populations include Neandertals of

western and central Europe and other contemporaries in north- ern Africa and the Middle East. In this latter region, there is extensive variability ranging from individuals approaching west- ern European morphology to those more similar to modern hu- mans. The Kebara 2 skeleton falls at the more robust end of this range ofvariability in the Middle East. Hence some palaeoanthro- palogists might not view Kebara 2 as a “Neandertal”; we refrain from making that assessment in this paper.

‘qhe mandible, in its ontogeny, originally of brachial origin (Meckel’s cartilage). is later replaced by dermal bone similar to that of other elements of the cranial vault. Small parts of the mandible remain from the original visceral skeleton, such as ossifications over the mylohyoid canal and the ossa mentales a t the symphysis. This shift from visceral to dermal bone may explain the variability of the mandible vs. the stability of the visceral bones during the human evolutionary process.

0 1990 WILEY-LISS. INC

138 B. ARENSBURG ET AL.

and Tillier, 1983; Heim, 1982) and Australo- pithecus robustus (Rak and Clarke, 1979).

The hyoid is often described as a “free- floating’ bone in that it has no direct articu- lation with other skeletal elements. How- ever, this description is misleading because the hyoid is connected through a set of mus- cular and ligamentous relationships to the larynx, phar nx, mandible, cranial base,

hyoid and larynx can be determined through an examination of the anatomical relations among these elements and adjacent bones, muscles, and vessels. The anatomy and de- velopment of this r e g h a r ~ faii1y wail known. In early fetal life the hyoid and the underlying larynx lie close to the naso har-

x and near the basicranium. In mi % fetal

tom of the larynx (cricoid cartilage) then lies at the level of the upper border of the fourth cervical vertebra. During the seventh fetal month the base of the larynx is found oppo- site the middle of the sixth vertebral body (Pressman and Kelemen, 1955; according to Table 2 in Magri les and Laitman, 1987, it may reach the miidle of C5), and in adult life it is at the lower border of the body of this vertebra. The upper tip of the larynx after birth (epiglottic cartilage) usually lies no higher than the lower border of the third cervical vertebra. The larynx changes not only its position in fetal life but also its anatomical relationship to the trachea and nasal passages. It becomes parallel to the former and angulated in relation to the latter (Negus, 1949).

It must be em hasized that chan es in the

bral column and the mandible occur primar- ily during intrauterine life, whereas changes in the morphology and size of this organ, as well as of each of its components, occur in childhood development, especially during uberty. Accordingly, the larynx of a new-

lorn human infant is roughly adult in posi- tion [from the base of the hyoid at C4 through the base of the cricoid at C6 (Meschan, 1985)J and fetal in morpholo .

the hyoid bone and the basicranium in- creases due to development of the maxilla and mandible and development and eruption of the teeth, but its relative position with regard to the vertebral column remains prac- tically the same. The postnatal “downward shift” of the larynx and hyoid is less than half

sternum, an B scapula. The position of the

Y ife these structures “descend,” and the bot-

position of the P . larynx relative to t a e verte-

With age, the abso F Ute distance between

the height of a vertebral body. The hyoid bone most specifically follows the develop- ment of the mandibular body height because of the close muscular attachment and depen- dence between the mandible and hyoid bone. This mandibular-hyoid relationship is formed by the attachment of the mylohyoid muscle to the hyoid, forming a sort of buccal diaphragm in the floor of the oral cavity. This diaphragm is reinforced inside and out- side by two muscles; the geniohyoid and anterior belly of the digastric, respectively. The attachment of these muscles is a t the lower and inner art of the mandibular svm-

muscle). The mylohyoid together with the eniohyoid and anterior belly of the di astric

oid bone and stabilize it in a more or less fixed position between the posterior end of the mylohyoid line (under and posterior to the third molar) and the inferior border of the mandible in front of the fourth cervical vertebra (see Romanes, 1981). It is in this last position that the hyoid bone is enerally

in exposure of the film). %hus the position of the hyoid bone and the

underlyin larynx in hominid fossils may be

and its muscle markings and contacts with the cranium are recovered. The distance be- tween the basicranium and the hyoid bone and underlying larynx is determinable, as mentioned above, from the combined height of the mandibular body, the maxilla, and the dentition. Because the hyoid is Dositinned at the gonial level. the mandibular ramus is also useful in determining its height.

A final element that may influence the distance between the basicranium and the hyoid bone is the form and size of the hyoid itself. Thus, a tall corpus hyoideus attached to vertically oriented greater cornua, such as is found in the gorilla or the chimpanzee, will act to reduce the hyoid-basicranial space. The hyoid bone from Kebara Cave in Israel

The principal measurements of the hyoid bone from Kebara (Fig. 1) alon with a com-

sentative great apes are given in Table 1. In all respects, the morphology of the Kebara 2 hyoid is within the range of modern human variation (see Arensburg et al., 1989). In- deed, the attachment areas for the infrahy-

yLysis and mylo ! yoid h e (for the mylohyoid

Emit the craniocaudal movement o f t a e hy-

seen in clinical radio raphy of t a e living (provided the patient c f oes not swallow dur-

assessed B airly accurately if the mandible

parative modern human samp K e and repre-

ANATOMICAL BASIS FOR SPEECH 139

TABLE I . Measurements (mmi of the hvoid from Kebara and that of modern hominoids

Modern humans’ Nonhuman primates Kebara 2 iT Mean SD Range Orangutan’ Gorilla’ Chimnanzee3

Total sag. diam. 35.5 11 35.65 3.2 30.0-39.8 36.0 80.0 44.0 Total trans. diam. 45.0 12 38.97 2.7 34.4-43.5 34.0 $5.0 (71.0) Body max. trans. diam. 24.6 48 21.35 2.7 14.4-27.2 19.0 33.0 24.F Body max. med. height 13.4 67 10.66 1.3 7.5-14.2 __ - __

‘Adult bones, both sexes, from archaeological and recent collections housed in the Department of Anatomy and Anthropology, Tel Aviv University, Tel Aviv, and the Laboratoire d’Anthropologie, Universite de Bordeaux 1, Talence. :One individual from the collection of the Peabody Museum, Harvard University.

individual from the collection of the Department of Zoology, Tel Aviv University. Measurement in parentheses is estimated. Due to difficulties in orientating the dry bone, the height of the body was not determinable.

0 1 2CM - Fig. 1. Hyoid of Kebara 2. Anterior view.

oid muscles on the ventral surface of the body are identical to those of modern hu- mans, as are the attachments for the hyo- glossus muscles on the greater horns. The Kebara 2 hyoid is also considerably different from the box-like hyoids of some great apes (cf. Fig. 2). The hyoid bones of the chimpan- zee and gorilla are “remarkably deep, box- like in shape, quite different from the narrow and horseshoe-shaped hyoids of man and of oran -utans” (Schultz 1969:74). The orang hyoi 3 differs from that of humans and the other apes in the more obtuse angle formed between the body and the greater cornua of the hyoid.

The metric traits of the Kebara bone have been corn ared with those of a large sample

(Arensburg et al., 1989; Table 1). Only the of hyoids P rom anatomically modern humans

transverse diameter ap ears to be signifi-

the accurate position of the greater horns relative to the body is somewhat difficult to assess because of the missing articular carti- lages. The variability of the shape and size of the human hyoid is manifested by the transversekagittal ratio of the bone defined by Papadopoulos et al. (1989; Table 4). The ratio in modern humans varies strongly ac- cording to the divergence of the greater horns, rangin from 0.97 to 2.33. In our sample of mo !? ern hyoids, the ratio ranges from 0.91 to 1.30 (S.D. 0.12). The Kebara 2 hyoid with its very divergent reater horns

modern human range of variation. The modern form and size of the Kebara 2

hyoid point to a basically modern hyolaryn- geal apparatus in Middle Palaeolithic peo- ples in terms of cor us and cornua size and

elements. An assumed “pongidization” of these structures in some Middle Palaeolithic specimens, as sug ested by Crelin (19871, is

cantly larger in the Ke E ara specimen, but

presents a ratio of 1.96, we f 1 within the

shape and the angu f ation between these two

not supported by t fl e Kebara 2 evidence. RESULTS AND DISCUSSION

The discovery of a complete hyoid bone from Kebara Cave pertains directly to the controversial question of fossil hominids’ (in- cluding Neandertal and other Middle Palae- olithic populations) ability to speak and ar- ticulate language. Although the cranium of Kebara 2 is missing, the preservation of the hyoid, mandible, and cervical vertebrae per- mits us to make some assessments about this linguistic argument.

Morphological studies relating to fossil hominid speech potential have focused on the comparative anatomy of the vocal tract in nonhuman primates, growing humans,

140 B. ARENSBURG ET AL.

Fig. 2. Hyoids of Kebara 2 and an adult chimpanzee. Anterosuperior view (actual size).

and adult humans as a guide for interpreting the fossils. According to Lieberman and Cre- lin (1971:220), Neandertals lacked the “ana- tomical prerequisites for producing the full range of human speech (e.g., flexion of the basicranium, a reduced distance between basion and the palate, and a low ositioning

claimed that human newborns. Neander- tals, and chimpanzees lack these prerequi- sites and show several anatomical similari- ties that make speech difficult or impossible.

Laitman and coworkers (Laitman et a1 . 1978. 1979: Laitman. 1985; Laitman and Reidenberg, 1988) later used the dimensions and form of the basicranium as an indicator of speech capabilities. They suggested an overall relationship (but not a structural or functional one) between basicranial changes during development and the position of soft tissue structures such as the larynx and pharynx. The degree of basicranial flexion is thought to be the critical speech indicator. Crania showing little or no flexion (such as in human infants, young children, and non- human primates) differ from those of adult humans; there is a highly positioned upper respiratory tract and limited vocalization. Neandertals seem to show a degree of platy- basia, according to measurements of La Chapelle-aux-Saints, La Ferrassie 1, Circeo 1, Saccopastore 2, Gibraltar 1, and Teshik-

of the hyoid bone and larynx). T ‘i: e authors

Tash (Laitman et al., 1979). Thus they are included with the linguistically limited.

All these studies emphasize that Neander- tals must have a high positioning of the hyoid and larynx, primarily because they have a lon flat basicranium. A high posi-

ryngeal space, and it is this reduced resonat- ing chamber that would prohibit the production of the full range of modern hu- man speech. Indeed, when Neandertal vocal tracts are modeled and tested for speech generation, they invariably are f~ulnil to be unable to produce the full range of vowei sounds characterizing human speech (Lie- berman and Crelin, 1971; Lieberman et al., 1972; Lieberman, 1984; Crelin, 1987).

These morphological studies on fossil hominid s eech have been widely criticized (see Carliie and Siegel, 1974; LeMay, 1975. Falk, 1975; Burr, 1976; Wind, 1978). Asid; from valid criticisms regarding the descrip- tion of anatomical relations or the use of poorly preserved fossil specimens to gener- ate models for the evolution of human speech, the major assumption of these works-that there is an association between the anatomy of the vocal tract, variation in cranial base morphology, and full phonetic capabilities-remains to be demonstrated. We have serious reservations about the in- terpretations of the data presented concern-

tioning o f t 8‘ e hyoid implies a small suprala-

ANATOMICAL BASIS FOR SPEECH 141

in the reliability of the basicranium as an

If Neandertal basicrania are flatter than those of modern humans (as per Laitman et al., 1979; Laitman, 19851, does it necessar- ily follow that speech (viewed in terms of supralaryngeal space) is affected? Indeed, a study of craniofacial associations by Solow (1966) provides evidence to the contrar

terior height are negatively correlated with basicranial flexion, suggesting that there is a “compensatory mechanism that tends to keep the nasopharyngeal volume inde en-

1966:125; also su ported by Bergland, 1963,

modern human, Neandertal, and other Mid- dle Palaeolithic basicranial flexion is consid- erable (see discussions in LeMay, 1975; Grosmangin, 1979; and diagrams and dis- cussion in Laitman et al., 1979). It is there- fore impossible to say whether the degree of difference between Neandertals and modern humans (Laitman et al., 1979) results in a statistically significant difference in su-

ralaryngeal space and phonetic quality. gtatements about the specific linguistic ca- pability of individual fossils (Crelin, 1987) are even more questionable.

The basic assertion that the hyoid and larynx of fossil hominids differed from those of modern humans, being ositioned higher

ative anatomical evidence and by the form and dimensions of the Kebara 2 hyoid, man- dible, and cervical vertebrae. First, a superi- orly situated hpoid and larynx in Neander- tals is untenable from an anatomical perspective. If this were the case, “new” (or more correctly archaic) relationships be- tween nerves, vessels, glands, and muscles would have to exist. If the hyoid were high, the muscles attached to it would have differ- ent functions. The anterior belly of the digas- tric would act as a hyoid depressor rather than a levator, and the geniohyoid would pull the hyoid forward instead of raising it (Falk, 1975). Did Neandertals lack a hori- zontal buccal diaphragm (formed by the my- lohyoid muscle) as seen in modern humans, or did they have a strongly oblique one fol- lowing the attachment of the muscle from the mandible to a hyoid body superiorly lo- cated at the level of the first and second cervical vertebrae? If the latter is true, then the mylohyoid nerve and its mandibular ca-

in 8 icator of speech capability.

demonstrated that maxillary width an 8‘ pos- He

dent of cranial base flexion” (So P ow,

cited in Solow). # urthermore, variation in

in the throat, is challenge 8 both by compar-

nal should have an upward, strongly oblique orientation in Neandertals. This does not seem to be the case. Middle Palaeolithic mandibles, including those of Neandertals, have mylohyoid grooves that clearly run downward and anteriorly as in modern hu- mans (based on Heim, 1976; Smith, 1978; Straus, 1962; and Trinkaus, 1983; as well as our own observations on Kebara 2, Amud 1, Qafzeh 9, Skhul V, Tabun I and 11, Regour- dou, and Krapina J and C), suggesting a suite of muscular relations similar to mod- ern humans must have been present.

Observation of the hyoid bone and its rela- tionships to the mandible and surrounding structures, as discussed above, makes clear the set relationship between hominid man- dibular dimensions and hyoid positioning. The flexion of the basicranium is irrelevant for determining the level of the hyoid. It is the dimensions of the mandible that are im ortant. Falk (1975) showed that the hy- oixhas a relatively fixed relationshi to the

of the inferior border of the mandible in chimpanzees, human newborns, and adults. In hominids with well-developed vertical di- mensions of the mandibular bod and ra-

eat basicranium-hyoid &stance is

distance is equally large. Fossil hominids generally have tall mandibular rami (Table 2). The tall mandibles of Middle Palaeolithic hominids strongly suggest a low position of the hyoid with respect to the basicranium and a large supralaryngeal space. The same relationship between hyoid and basicranium does not exist in apes, but not because of the form of the basicranium: Although the height of the mandible is great in pongids, the hyoid and underlying larynx are positioned close to the basicranium due to kyphosis of the vertebral column (in con- trast to the cervical lordosis seen in function- ally bipedal hominids). The position of the hyoid relative to the mandible is the same for hominids and pongds (Falk, 1975; Swindler and Wood, 19731, whereas the position of the hyoid relative to the cranial base is contin- gent on head and neck posture. This latter point can be illustrated clinical1 when pa- tients are radiographed with t H e head in flexion and extension (see Fig. 3). When the head is flexed, approaching the conditions of kyphosis as seen in apes, the distance be- tween the body of the hyoid and the basicra- nium (here determined by the temporoman-

mandible, lying roughly at or below t K e level

found, a 8‘ ecause their basicranium-gonion

142 B. ARENSBURG ET AL,

Fig. 3. Radiographs of an adult human female. Distance between the body of the hyoid (white arrow) and the temporomandibular fossa (black arrow) is indicated. a: Head flexed, creating a condition similar to kyphosis. b: Head in anatomical position.

TABLE 2. Mandibular measurements (mmj from Middle Palaeolithic and modern humans

Middle Palaeolithic humans' Modern Middle humans' KMHP East (n) - Europe (n) (n = 15)

~ ..

Syrnphyseal ht. M 6 9 ) 42.1) 30.3-.:7.3 (6) 34.7, 3.9l (14) '32.8, 2.53 Body ht. men. for. (M69i1) 36.9 27.5-40.3 (6) 3i.5,3.7:1 (19) 31 -7; 2 . Y Gonion-cond. ht. (M70) 61.7 59.4-70.5 (5) 61.0-67.0 (3) 62.1, 4.3" M3-M3 ext. breadth 78.0 71.0-76.3 (6) 68.0-75.5 (3) 64.4, 3.8?

:Middle East and Europe sample from Tillier et al. (in press). Except where noted, ranges are given. aModern sample of Bedouins measured in Dept. Anatomy and Anthropology, Tel Aviv University. Mean, SD.

dibular fossa) is shorter than when the head is in anatomical position (cervical lordosis). For upright, bipedal Neandertals with a modern inclination of their cervical verte- brae (Arambourg, 1955; Patte, 1955; Straus and Cave, 1957; Piveteau, 1966; Heim, 1976; Trinkaus, 1953), the hyoid and larynx must be low relative to the cranial base. If this is true, the Neandertals should have suprala- ryngeal spaces approximately the same size as those of modern humans, and we would

predict no significant differences in articula- tory capabilities.

We have mentioned several reasons why the hyoid and larynx of Neandertals and other Middle Palaeolithic peoples should theoretically be positioned as in modern hu- mans. The Kebara 2 s ecimen provides the

manner. It is most important to emphasize that the skeleton of Kebara 2 exhibits both similarities and differences when compared

opportunity to check t g is in a more specific

TAB

LE 3

. M

easu

rem

ents

(mm

) of

ceri

xal

ver

tebr

al b

ody

heig

hts

(V-u

entr

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for M

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t an

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uman

s ['om

hin

d n

iiil

l~rn

c l_..._..̂

"I

l.."l

(n =

20)

_

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__

_~

-_

Whi

tes

(n =

92)

-

Bla

cks

(n z:

88)

I C

hape

lle

Mea

n R

ange

M

ean

Ran

ge

Mem

R

ange

M

ean

Ran

ge

Ran

ge

Ran

ge

La

Shan

idar

Sh

anid

ar

Shan

idar

R

egou

rdou

Fer

rass

ie

La

__

_~

-

Keb

ara

I If

IV

Sk

kulV

1

VD

V1

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DV

DV

DV

DV

DV

D

V

D

V

1) V

~ -

~ ---...I

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~_

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CS w

ithd

ens

31.5

13

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-

15.7

- -

- I

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- -

39.4

:1

5.0-4

5.4

-

-

- 31

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2.0

-

--

----

-

-

--

-

-

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c2 15

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13.5

-

- 20

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15.7

- -

lii,lO

13

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- -

-

- -

c3

11.0

(10

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- 11

.0

12.5

-

- -

10.5

10

.5

12.3

12.

5 -

- -

14.1

11

.0-1

7.0

14.0

10

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7.0

9.0-

1 7.0

11

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7.0

10.0

-15.

0 c

4

11.0

-

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11.0

12

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0.0

12.5

8.

3 $1

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0 10

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2.0 -

- -

13.6

10

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6.2

13.7

11.4

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9 9.

5-16

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9.5-

15.0

9.

5-14

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C5

10.0

11

.0

9.5

12.5

11

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13.0

10.

1 -

9.5

10.8

12

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12.0

11

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11.5

-

12.7

10.5

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2 13

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10.6

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2 10

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6.0

10.0

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0 11

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4.5

C6

10.8

11

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10.4

12

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12.0

13

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9.7

12.4

(10

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(13.

0) -

- 12

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12.1

-

12.7

10

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5.9

13.6

10

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7.0

9.1-

16.0

10

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4.0

10.5

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6 C

7 13

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12.0

13

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4.0

(13.

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14.0

) - -

(12.

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13.0

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13.4

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14.4

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6.3

15.0

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8.2

10.1

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1 11

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6.5

12.0

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5

C4

46

31

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32.9

-

34.0

-

- -

28.0

-

32.0

-

- -

- -

-

C5-

C7

33.8

--

- -

36.0

-

29.8

-

32.0

-

- -

37.0

-

37.0

-

- -

--

-

- -

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_I

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Tot

al C

2-C

7 87

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- 10

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3 -

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- 88

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82

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21.6

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98.0

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;M

iddl

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laeo

lithi

c sa

mpl

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re fr

om M

cCow

n an

d K

eith

(193

9) P

ivet

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(196

6), H

eim

(19

76),

and

Tri

nkau

s (19

83).

Figu

re in

par

enth

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are

est

imat

ed.

Mod

ern

data

on

U.S

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tes

and

blac

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om L

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r (19

39) a

nd o

n il

com

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). T

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the d

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nd su

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Tab

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). T

rink

ausr

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ted

the

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8.0m

m b

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t dor

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. 'R

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a 99

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144 B. ARENSBURG ET AL

Fig. 4. Hyoid and mandible of Kebara 2. Superior view (actual size).

to modern humans. A combination of mor- hological and metrical comparisons of the

&oid_ mandible. and cervical vertehrae is the key to an understanding of the Kebara 2 vocal tract. First, similarities are seen in both the size and the form of the hyoid. The facets for the attachment of the supra and infra hyoid muscles are in the same positions and orientations and are similar in size to those of modern humans. Kebara 2 is also similar to modern humans where the rela- tions of the hyoid to the rest of the visceral skeleton are concerned. In particular, the orientation of the mylohyoid ridge and sul- cus on the mandible indicates the same set of muscular and neurovascular relationships as seen in modern humans.

A second area where Kebara 2 is similar to modern humans is in the morphology, orien- tation, and dimensions of the cervical region (Arensburg, in Bar-Yosef and Vandermeer- sch, in preparation). Kebara 2 has all 32 vertebrae preserved, making it the only Mid-

dle Palaeolithic specimen with a complete column. Referring specifically to the cervical portion. there are no significant mnrphnlng- ical differences from modern humans. a d the individual ventral and dorsal hei hts of

dle Palaeolithic and modern human samples (Table 3). Even without the discs, which are the main contributors to cervical curvature, the generally greater ventral body heights indicate that Kebara 2 exhibits cervical lor- dosis. When the length of the total cervical segment is calculated (using a reconstruc- tion of the dens based on the odontoid facet of the atlas), the Kebara 2 neck is 87.3 mm, a ain within the modern ran e of variation.

ment, considered along with the dimensions of the mandibular ramus (Table 2) and the hyoid itself, provide evidence for a pattern of modern human spatial relationships among these elements.

Finally, where Kebara 2 differs most strik-

the bodies are within the range of bot Fl Mid-

Tiese two characteristics oft a e cervical seg-

ANATOMICAL BASIS FOR SPEECH 145

ingly from modern humans is in some dimen- sions of the mandible (Tillier et al., in press). The heights of the symphysis and of the body at the mental foramen and the external breadth at the third molar exceed those of a modern comparative sample (and are also large in comparison with other Middle Palaeolithic hominids; Table 2). The Kebara 2 mandible has an extreme1 tall and broad

elements is illustrated in Figure 4. It is also evident from this comparison that the small hyoid would not have occu led a very large

evidence for a reduced supralaryngeal space in Kebara 2.

Kebara 2 illustrates the mosaic evolution of the visceral skeleton in fossil hominids. “Archaic” features such as the dimensions and robusticity of the mandible are com- bined with a hyoid basically indistinguish- able from that of modern humans. Rather than regarding the Kebara 2 hyoid as “modern” or derived, we suggest that it may instead represent a functionally and struc- turally generalized element in the visceral skeleton, similar to the case with the bones of the middle ear (Arensburg and Nathan, 1972).

CONCLUSIONS

The discovery of the first fossil hominid hyoid bone from Kebara provides important insights into the vocal tract of Middle Palae- olithic hominids, because a previously un- known ortion of the anatomy is available

can be evaluated. The bone itself is not nota- bly different, in either size or morphology, from that of modern human hyoids. The relations of the hyoid to the mandible and cervical vertebrae probably did not differ from the modern pattern; the Kebara neck a pears to be anatomically and proportion- a P ly similar to that of living peoples. These new data stron ly suggest that Middle Palaeolithic eop e shared structural rela-

their vocal tracts. They appear to be as “an- atomically capable” of speech as modern hu- mans when hyoid positioning and suprala- ryngeal s ace are the criteria considered.

discovery, yet the evidence for marked simi- larities of this bone to those of living peoples cannot be easily dismissed; this research has

corpus cou led with a hyoi 2 of modern pro- portions. .p he contrast between these two

portion of the vocal tract; R ence there is no

for atu ir 3- and its anatomical relationships

tionships wit “hii modern humans in terms of

The hyoi 8 bone from Kebara is a “singular”

demonstrated that it is a component in a suite of morphological relationships that col- lectively display a modern human configura- tion. Hopefully the hyoid and related bones of other fossil hominids will be recovered in the future, and we believe that this will add to our understanding of the vocal and upper respiratory organs of fossil humans.

ACKNOWLEDGMENTS

We are grateful to Prof. D. Pilbeam, Har- vard University, and to Dr. J.P. Garlick, Cambridge University, for generously mak- iiig available the primate collections; t,o Dr. Christopher Dean, University College of London, for his critical and most helpful review of this paper; to Prof. M.S. Goldstein, Tel Aviv University, and Michael Speirs, University of Pennsylvania, for their critical reading; and to A. Pinchasov for the photo- graphs.

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