HUMAN

EVOLUTION

Vol. 3 - N.

5 ( 3 2 9 - 3 3 4 ) - 1988

v

S. Zivanovid Zavod za Anatomiju, Medicinski Fa-

kultet, Hajduk VeOkova 3 21000 NOVI SAD, Yugoslavia.

Keywords: Temporal region,

Supramastoid ridge, Mesolithic, Padina, Iron Gate Gorge

The Temporal Region and the Supramastoid Ridge in Mesolithic Skulls from Padina in the Iron Gate Gorge of the Danube Studies of the morphological features of the temporal region of mesolithic skulls from Padina in the Iron Gate Gorge of the Danube revealed a very prominent and large supramastoid ridge which is the most striking feature in skulls of both sexes. Mastoid processes were larger in male skulls, but in 25% of the cases there was an overlap between the size of the processes in male and female specimens. The mastoid ridge was prominent in both sexes. The digastric fossa was always well defined in both sexes and in the two thirds of the skull specimens it was deep. The posterior root of the zygomawas prominent in all the skulls, but it was better developed in the male specimens. The parietotemporal suture in both sexes rises above the level of the pterion. There were no morphological or anthropometrical differences between the left and the right side of individual skulls outside the limits of natural asymmetry. All these morphologicalcharacteristics of the temporal region may help in racial and sexual diagnosis of the Mesolithic skulls from the Iron Gate Gorge.

Introduction Extensive archaeological excavations in the Iron Gate Gorge of the Danube, which commenced in 1966, revealed a number of skeletal remains at the Padina site (44~ 22~ Skeletons at Padina have been unearthed during the 1968-1970 campaign (JovANOVI~, 1968, 1969, 1972; 7.IVANOVIS, 1975). Detailed osteological and anthropological studies of the skeletal remains followed (ZIVANOW~, 1974, 1975, 1976, 1979). Direct radiocarbon dating of the collagen samples from the femora of these skeletons, performed in the British Museum Radiocarbon Laboratory in London, has shown them to belong to the early Holocene period c 8-9000 BP (BURLEICHG& ZIVANOVId, 1980). Detailed studies of the skulls concentrated first on the masticatory apparatus (ZIVANOVI~, 1976) and in this study the specific morphology of the temporal region of the Padina skulls has been described and discussed to complement the previous reports.

Material and Methods Most of the skeletons recovered at Padina were in a very poor state of preservation (~.IVANOVld, 1974, 1975) and only one complete skull has been found. All the other skulls were fragmentary. Nevertheless, the temporal bones, being the strongest parts of a skull, remained in the majority of cases so that the temporal region of 14 skulls could be studied on both sides. In describing the morphology of the temporal region in general, and the supramastoid area in particular, it was important to observe and compare the left and the 9

Editrice I1 Sedicesimo - Firenze

ISSN 0393-9375

330

ZIVANOVIC

TABLE 1 - Sex and State of Preservation of the Temporal Region. Sex State of preservation Right Left

Male

Female

Good

Poor

Fragments

Good

Poor

Fragments

1 1

3 4

4 3

0 0

2 2

4 2

right side of each skull because of the natural and acquired asymmetry of the skulls. Temporal regions of 8 male and 6 female skulls belonging to adult, mature or senile individuals were studied in detail. Diagnosis of sex was based on the sexual characteristics of hip bones and femora (Table 1). In studying the morphology of the temporal region of the skulls the following features were observed: Mastoid process - - The size of the mastoid process was assessed by comparison with three standard specimens of recent skulls from the same area representing small, medium and large processes. The respective lengths of the processes in these three standard specimens were 21 ram, 28 mm and 35 mm. Using sliding calipers the length was measured from the cross point on the line which runs horizontal across the upper part of the mastoid process on a level with the upper border of the external auditory meatus and the vertical line going downwards to the apex of the process at the right angle to the horizontal line. In measuring the size and the length of the mastoid process a method developed by KEEN (1950) was adopted, because it gives a satisfactory guidance in assessing the length and the size. It has been well known for quite some time that there are sexual differences in the size of the mastoid process, but the previous statements (prior to KEEN, 1950) have not been quite proven. Mastoid ridge - - The line of the attachment of the sternocle idomastoid, splenius capitis and longissimus capitis muscles may be marked in recent skulls by a roughened ridge, which may be prominent, slight or absent. The size and shape of the line was observed and noted. Digastric/ossa - - The digastric fossa is situated on the medial side of the mastoid process and gives attachment to the posterior belly of the digastric muscle. The posterior part of the fossa may be either expanded beyond the mastoid process and thus apparent on the lateral side, or it may not be expanded and concealed by the mastoid process. Looking from below the digastric fossa may be shallow, medium or deep, with smooth or with ridged walls and the well defined, moderate or not clearly defined margins. Attention was paid to these points and all observations were recorded. Temporosphenoidal swelling - - The temporal fossa may be diminished in depth postero-inferiorly and this may be caused by the relative enlargement of the temporal lobe of the brain, which extends the pressure on the temporal squama and forms a protrusion into the external temporal fossa. Posterior root o~ the Zygoma - - The posterior root of the Zygoma forms a ridge at the upper border of the external auditory meatus which may be described in three categories, namely slight or hardly visible, intermediate and very prominent or marked. Supramastoid crest or process - - The supramastoid crest serves for the attachment of the temporalis fascia and in recent skulls may be of either slight moderate or marked development. In some skulls it may form a torus or a process. A definite supramastoid groove is associated with moderate or with marked supramastoid ridges and processes.

331

THE TEMPORAL REGION

P a r i e t o - t e m p o r a l s u t u r e - - The position and contours of the parieto-temporal suture were observed and recorded. This investigation of the morphological characteristics of the temporal region was undertaken to note the racial characteristics of the mesolithic crania from Padina which are likely to be influenced by the extensively developed masticatory apparatus (7,IVANOVI6, 1976). Also sexual differences may be of some use in diagnosing sex of the skeletons from this period in the Iron Gate Gorge.

Observations and Results Examination of the skulls from Padina showed that all the skulls, of both sexes, were relatively similar in shape and belonged to the same racial type, since they possessed nearly identical morphological and anthropological features. The left and the right sides of each skull were also morphologically identical and no significant differences in the form and shape could be detected. The occurrence of various formations and their size, depth or prominence are given for both sexes in the following table ( T a b l e 2). M a s t o i d process - - This process is larger and better developed in the males than in the females. In 75% of the male skulls it is large, and it was never shown to be large in the female skulls. In 66% of the female and in 25% of the male skulls it was medium in size. It was never small in male, but it was small in 25% of the female skulls. In both sexes there is a substantial percentage of skulls with a mastoid process of medium size.

TABLE 2 - Morphological characteristics o] the Temporal Region. Sex

Male

Incidence

Female

Number

%

Number

070

Mastoid process

small medium large

0 2 6

0 25 75

2 4 0

33 67 0

Mastoid ridge

absent slight prominent

0 1 7

0 13 87

0 1 5

0 17 83

Digastric fossa

shallow medium deep

0 3 5

0 38 62

0 2 4

0 33 67

Temporosphenoidal swelling

absent slight prominent

8 0 0

100 0 0

6 0 0

100 0 0

Posterior root of Zygoma

slight intermediate marked

1 3 4

13 37 50

1 3 2

17 50 33

Supramastoid ridge

slight moderate marked

0 1 7

0 13 87

0 2 4

0 33 67

332

ZIVANOVIC

Figure 1. -- Two skulls from Padina showing the morphologicalcharacteristics of the Temporal region. M a s t o i d ridge ~ The mastoid ridge was always present in all the skulls of both sexes. Only in one male and one female skull was the ridge slight, while in all the other skulls of both sexes the ridge was prominent. Attachments of the well-developed sternocleidomastold, strong splenius capitis and longissimus capitis muscles lead to the formation of such a prominent ridge. Digastric fossa - - In all the skulls the posterior portion of the digastric fossa was expanded beyond the mastoid process and thus apparent in norma lateralis. The fossa was always well-defined and ridged and in two thirds of the skulls of both sexes it was deep. In the remaining one third of the skulls the fossa was of moderate depth, but its sides were well-marked and ridged. T e m p o r o s p b e n o i d a l swelling - - The swelling of the postero-inferior part of the floor of the temporal fossa which may be caused by the relative exaggeration of the temporal lobe of the brain, was absent in all the examined skulls. In recent skulls the swelling is very prominent in young individuals. Posterior root of Z y g o m a ~ In all the skulls from Padina this was present in various degrees of prominence. It was well marked in half of the male and in one-third of the female skulls. It was intermediate in one half of the female and in one-third of the male skulls. It was slight only in one male and in one female skull. The well-marked ridge was

THE TEMPORAL REGION

333

continuous with the supramastoid ridge forming the proper supra-auditory tours. The marked variety forms a sharp ridge, while the intermediate variety has a rounded contour. There are visible sexual differences in the size and the shape of the posterior root of zygoma. The posterior ridge was much larger in male skulls, but there were some specimens where the sexual differences were not marked at all. S u p r a m a s t o i d crest - - The supramastoid crest, which serves for the attachment of the temporal fascia, was always present in all the skulls of both sexes. It was never slight, and it was moderate in size only in one male and two female skulls. Most of the skulls had a very marked and prominent ridge. The shape and the size of this ridge is very characteristic for the Padina population. In most of the skulls it has a form of a supramastoid process because it is so prominent. P a r i e t o - t e m p o r a l s u t u r e - - The suture between the squama of the temporal bone and the parietal bone was found always to be convex upwards. It rises above the level of the Pterion. The posterior limb of the suture descends sharply as an oblique line going towards the apex of the mastoid process (Figure 1).

Discussion

The mastoid process of the temporal bone is a compound structure formed by the squamosal part of the temporal bone which forms its anterior fifth and the posterior part is the proper mastoid process (SeJIvId, 1948). A number of muscles are attached to its lateral surface. Thus, although the size and the shape of the mastoid process may be influenced genetically, strong muscle attachments also play a role in the morphology of its lateral side. In Padina skulls there were clear sexual differences; the size of the mastoid process is much larger in the male, but in at least one quarter of skulls there is an overlaping of sizes so that the size of this process alone can not be used as a singular proof of the sex of a skull. In most of the recent skulls mastoid ridges or crests are large in individuals with small mastoid processes. Small crests are found in large processes probably because of the attachments of sternocleidomastoid muscle which are more flat and widely spread on a large process, while large crests on small processes are necessary to give the sufficient attachment area to the muscle. As it was stated previously the skulls of the mesolithic population at Padina have well-marked mastoid ridge in both sexes. It seems that the strong sternocleidomastoid muscle of substantial size in these individuals managed to influence the surface of the bone to give rise to the mastoid ridge which became a specific morphological characteristic of these skulls. A similar observation may be true for the digastric fossa which is usually deep in both sexes or, when it is medium in size, does not expand beyond the mastoid process. The fossa was never small nor shallow in Padina skulls. Sexual differences in the size and the expansion of the digastric fossa were practically insignificant. Absence of the temporosphenoidal swelling of the squama may be due to the fact that all skulls from Padina belonged to mature and older individuals and the swelling is more common in the skulls of juvenile or younger adult individuals. The posterior root of the zygoma was medium or large in all but two skulls, one male and one female. It forms a ridge at the upper border of the external auditory meatus, and if this ridge is very prominent it is continuous with the supramastoid crest or process. The shape of the posterior root of the zigoma has, in Padina skulls some features of the so called <~Boskop>> type, described by GALLOWAY (1937) in African skulls.

334

ZIVANOVIC

Supramastoidal ridges serve for the attachement of the temporal fascia and are usually continuous with the superior temporal line in recent skulls (SLJIVIC, 1948). In a study of sexual differences in a series of skulls KEEN (1950) found that the degree of development of the supramastoid ridge may provide useful information for sexual differentiation of skulls. In the present series of mesolithic skulls from Padina it was not possible to make clear sexual diferentiation by the shape and the size of the supramastoid ridge because most of the skulls of both sexes had a very well-marked ridge. None of the skulls found had slightly developed or absent ridses. The masticatory apparatus was very well developed and very strong in Padina skulls (ZIvANOVId, 1976) and its seems that this influenced the development of the supramastoid ridges. Their size and form became a characteristic indicator of Padina skulls, because the function, as well as the heredity (SCOTT, 1957) contributes to its size and form. In Padina skulls there was a large process in place of the supramastoid ridge which was well-developed and ovally elongated in shape. The shape of the parieto-temporal suture is described as another hereditary feature of the skulls (STEWART, 1933; GALLOWAY,1937). The shape of the parieto-temporal suture described in Padina skulls is a racial characteristic of this population.

References BURLEIGHR., ZIVANOVldS., 1980. Radiocarbon dating o/a Cro-Magnonpopulation from Padina, Yugoslavia, with some general recommendations for dating human skeletons. Z. Morph. Anthrop., 7G: 269-274. GALLOWAYA., 1937. The characteristics of the skull of the Boskop type. Amer.J. phys. Anthrop., 23:31-46. JOVANOVI~B., 1968. Padina, naseljestarijeg neolita i starijeggvozdenog doba. Arheolo~kiPregled, 10: 89-91. JovANOVldB., 1969. ChronologicalFrames of the Iron Gate Group of the Early Neolithic Period. Archeologia Iugoslavica, 10: 23-38. JovhNOVldB., 1972. The autochthonous and the migration components of the early neolithic in the Iron Gate. Balcanica, 3: 49-58. KEENJ., A., 1950. A study of the differences between male and female skulls. Am. J. Phys. Anthrop., 8: 6578. SCOTTJ., 1957. Muscle growth and function in relation to skeletal morphology. Amer.J. phys. Anthrop., 15: 197-236. SLjIVld B., 1948. Osnovi Osteologije, Nau~na knjiga, Beograd. 7,IVANOVldB., 1974. Rapport pr3liminaire sur les r3sultats des recherches anthropologiques relatives aux squelettes de Padina sur le Djerdap.Starinar, 24-25: 139-153. ZIVANOVldB., 1975. A note on the anthropological characteristics of the Padina population. Z. Morph. anthrop. , 66: 161-175. ZIVANOVldB., 1975. Mesolithic population in Djerdap region. Balcanica, 6: 1-7. 7.IVANOVldB., 1976. Cromagnon in the Iron Gate Gorge of the Danube. Nature, 260: 518. 7.IVANOVldB., 1976. The masticatory apparatus of the mesolithic Padina population. Antropolo~koDru]tvo Jugoslavije, Posebna izdanja, 3: 79-96. 7.IVANOVldB., 1979. Further Evidence on Cro-Magnon Man in the Iron Gate Gorge of the Danube. Current Anthropology, 20: 805. Rec.: 1 May 1987. Acc.: 15 February 1988.