Among the Middle Pleistocene human remains discovered in Biache-Saint-Vaast (Pas-de-Calais, France), three cranial fragments were attributed to the same individual: Biache-Saint-Vaast 2 (BSV2). Three-dimensional virtual imaging methods have been used to assemble the various bones and to study the endocranial cavities. The fact that these remains showed most of the classical Neanderthal characteristics as well as several plesiomorphic characteristics suggests the existence of a phyletic relationship with the early European Neanderthals.
Parmi les restes humains découverts à Biache-Saint-Vaast (département du Pas-de-Calais, France) et datés du Pléistocène moyen tardif, trois fragments crâniens ont pu être attribués à un même individu : Biache-Saint-Vaast 2 (BSV2). L’imagerie numérique tridimensionnelle a été utilisée pour articuler et étudier virtuellement les différents ossements. L’observation, sur ces restes, d’une majorité de caractères observés chez les Néandertaliens classiques associés à plusieurs caractères plésiomorphes est en faveur d’une appartenance phylétique aux premiers Néandertaliens d’Europe.
Biache-Saint-Vaast (Pas-de-Calais Department, France) is located between the towns of Arras and Douai in a valley on the left bank of the Scarpe River. The site (50°18′N, 02°56′E), which is located at mid-height in this valley at an altitude ranging between 44 and 56 meters, is oriented south/southeast (
All the human remains originated from layer IIa (
Two fragmented human skulls were excavated at two places in layer IIa. Fragments of the parietal and temporal bones, an almost complete occipital bone, a portion of the
The other human bone fragments were identified on 8 November 1986 by P. Auguste during a study on the faunal bones. They originated from the same archeostratigraphic level as the other human remains and included a frontonasal fragment and fragments of the left parietal bone, the left temporal bone and the sphenoid and occipital bones. An anatomical connection was traced between the temporal bone, the greater wing of the left sphenoid bone, and the left parietal bone, which suggested that they belonged to the same individual (Biache-Saint-Vaast 2 or BSV2). The frontonasal and occipital fragments were also attributed to the same individual because their dimensions were compatible and because they were located in topographic proximity at the site.
The aims of the study on the BSV2 fossil were: to analyse its anatomical characteristics; to perform virtual reconstruction of BSV2; to discuss its phyletic position.
The frontal bone was damaged
The frontal bone shows multiple disoriented fractures including three major ones. A posterior fracture extends transversely from the right frontotemporal landmark to the left third of the squama, from where it is prolonged obliquely towards the left coronal suture. A second fracture (D,
Few gaps are present on the outer table of the squama.
This bone, of which only 6 fragments still exist (
The left temporal bone consists of 6 fragments (
The semicircular canals and the cochlea are preserved. The bony labyrinth was studied using 3-D imaging methods, and the results obtained will be presented below.
The endocranial surface was eroded
Only 2 fragments of the temporal side of the left greater wing of the sphenoid bone are still present (
The 3 remaining fragments correspond to the basilar part of the occipital bone and the 2 condyles (
It is difficult to estimate the age of this individual in the absence of teeth and long bones. The fractured frontal bone makes it possible to observe the presence of the frontal sinuses, but according to
The Biache-Saint-Vaast 2 cranial fossils both have a fairly robust morphology, with a marked frontal torus and a thick parietal bone. Based on comparisons between the 2 human fossil remains originating from the Biache-Saint-Vaast site, BSV1 and BSV2, the parietal bone of BSV2 shows a fairly marked thickening between the superior and inferior temporal lines, and the mastoid process is more highly developed than in BSV1. These differences in the robustness of these two individuals may be sex-related differences: the BSV2 individual may have been a male and the BSV1 individual may have been a female. However we cannot rule out the possibility that these were simply inter-individual differences; whereas the possibility that the difference in size was an age-related difference can probably be ruled out: based on BSV1 age at death (
Only the lower part of the frontal bone can be studied. The circumference of the orbits is round. One right supraorbital notch, one right supraorbital foramen and one left notch are present. The supranasal region is rough. The surface of the orbital arch and that of the right zygomatic process of the frontal bone are vermiculated. The supraorbital torus is of type III in Cunningham's scheme of classification (
The depth of the left temporal surface with respect to the temporal line is more than 10 mm. This feature cannot be measured on the right side.
The frontal sinuses are well developed (
In the endocranial view, the frontal crest was found to measure 10 mm in height and more than 40 mm in length. Its lower base is not preserved, as observed in the case of the foramen cecum. The crest is frayed and curvilinear at the bottom, while the upper part widens and deviates toward the right. The sagittal sulcus and the orbital plate are no longer present. The cerebral convolutions are barely visible.
The parietal bone is thick (11 mm at the top of the lambdoidal suture). In the posterior part, an osseous thickening fills the space between the inferior and superior temporal lines. Posteriorly, a change in the parietal bone curve was observed just under the superior fracture. This may correspond to a similar prelambdatic depression to that observed within the occipital chignon.
In the endocranial view, the meningeal impressions are very strongly marked. The groove in the bregmatic branch of the middle meningeal artery is not visible because its contour merges with the anterior fractures of the parietal bone. The lambdatic branch of the middle meningeal artery reaches the posterior third of the parietal bone. Its groove is strongly marked, 1.5 mm wide, and gives rise to at least 2 collaterals. The well preserved distal groove in the lambdatic branch approaches the lambdoidal suture: the first collateral turns off towards the vertex before reaching this suture and then merges with the fracture. The end of the obelian lambdatic branch is trifurcated.
The supramastoid crest is strongly marked and smooth. The suprameatal crest cannot be described because of a gap. The mastoid crest is also marked and along with the supramastoid crest, it delimits a supramastoid sulcus. No anterior mastoid tubercles (
The external auditory meatus is elliptical, and its main axis is oriented from superior to inferior. The thickness of the tympanic plate decreases from the back to the front. No clearly distinguishable parts could be seen in the tympanic plate. The tympanic part is orientated coronally. A
Anteriorly, the entoglenoid process is prominent. The articular eminence is also proportionally small. The notch corresponding to the articular fossa is not very deep. This articular fossa looks rather narrow.
The digastric groove, the base of the styloid process and the stylomastoid foramen are not aligned because the styloid process is more medially placed.
The juxtamastoid eminence has a semi-circular shape from the top of the eminence (posteriorly with respect to the mastoid foramen) to the antero-inferior end. This crest does not show an occipital part, but the juxtamastoid eminence reaches the occipito-mastoid suture, which it follows without crossing it before passing it by. The juxtamastoid eminence, which was not found to be divided by the occipital groove, is more highly developed than the mastoid process.
The mastoid notch does not join the stylomastoid foramen. The mastoid notch is broad and looks open anteriorly, but includes a small medial bone elevation. The walls of the mastoid notch are very steep, which contributes to its triangular contour, forming a V-shaped pattern.
The preserved portion of the sphenoid bone is very small. No anatomical observations could be carried out on this cranial component, but it does not seem to be very thick.
Between the 2 basilar surfaces, the pharyngeal tubercle lying opposite the pharyngeal fossette is only slightly marked.
Virtual imaging methods were used to check the position of the fragmented remains that were reassembled manually after their discovery, and to propose a virtual assembly of the various cranial fragments on which to base our comparisons between BSV2 and other cranial fossils from the Middle and Late Pleistocene periods. Although we could have completely cleaned the fragments and reconstructed the skull manually, we decided to use medical imaging methods in order to protect the fossil from further damage.
Virtual reconstruction was performed by isolating the fragments and reassembling the pieces using CT scans and 3-D image processing methods. The fragments were CT scanned with a General Electric Light Speed scanner at the
When first discovered, the right and left frontal fragments were stuck together in the wrong position, resulting in an unnatural degree of asymmetry. The fragments of the left greater wing of the sphenoid bone were also incorrectly assembled. In order to prevent the risk of damaging the fossils when intervening directly on the fragments, virtual repositioning methods were used. The frontal fragments were assembled in line on the right plane of fracture (D) (
The fragments of the left greater wing of the sphenoid bone were dissociated in the same way.
The various bone fragments were then repositioned in relation to each other (
The accuracy of the virtual positioning was tested using a chimera. The posterior part was assembled by mirroring the BSV2 parietal, temporal, and sphenoid bones and adding the upper part of the BSV1 parietal bones and the BSV1 occipital bone. Because of the deformations undergone by BSV1, we mirrored the right side. BSV1 was used for this purpose because the two skulls are of a similar size and shape. The frontal squama was reconstructed by mirroring the right side of Krapina 3, another anatomically similar skull. This enabled us to simulate the orbital rim and to model the Frankfurt plane. The chimera thus obtained served to check the accuracy of the positioning of the BSV2 remains.
The petromastoid region of the temporal bone of BSV2 is highly pneumatised (
The interorbital breadth is 23 mm. The thickness of the squamous part of the frontal bone ranges between 6 and 7 mm. The minimum frontal breadth (M9 according to
The parietal-temporal arc M27(1) was found to measure 87.5 mm in length, with a chord M30(1) 81.6 mm in length. The parietal-temporal index of the curve therefore is calculated to be 93.2. The preserved portion of the lambdoidal suture measures 54.7 mm. The maximum width between the superior and inferior temporal lines is 16 mm. The thickness of the parietal bone ranges between 12 mm at the level of the thickening between the temporal lines, 10.4 mm at the level of the asterion, and 9.2 mm at the level of the parietal notch.
The total length of the temporal bone is 80.5 mm. The length of the squama is 61 mm. The height of the squama cannot be determined because of the poor state of conservation of the inferior part of the parietal bone. The thickness at the center of the squamous part of the temporal bone is 8.3 mm. The distance between the parietal notch and the antero-inferior extremity of the mastoid process (
The thickness of the zygomatic process varies relatively little. Four thicknesses were measured as described by
The pneumatised part of the petromastoid region occupies a volume of 2054 mm3. Some of the pneumatic cells are relatively large, especially those located in the posterior and postero-inferior parts of the temporal bone. The dimensions of the semi-circular canals given in
No measurements can be obtained on the severely damaged sphenoid bone.
The width of the foramen magnum (M16: 29 mm) was determined by mirroring the occipital fragment. The left occipital condyle is 19.9 mm long, 13.5 mm wide and 7.3 mm high.
Two profiles were drawn up in order to compare BSV2 with Middle and Late Pleistocene hominids originating from Europe and the Middle East: Arago 21, Sima de los Huesos 5, Petralona, La Chapelle-aux-Saints, Neanderthal, La Ferrassie 1, Monte Circeo 1, Amud 1, Krapina 3, and Biache-Saint-Vaast 1.
The chimera was used to position the BSV2 frontal bone with respect to the Frankfurt plane. The various skull profiles were aligned by superimposing the nasion (
A coronal profile of the parietal and temporal bones was drawn up, using the parietal notch and the antero-inferior extremity of the mastoid process as landmarks (
The sagittal profile of the preserved portions of the frontal bone of BSV2 is similar to that of Krapina 3. The profile of the glabellar area of BSV2 showed a weaker curvature than that of Arago 21, La Ferrassie 1, Neanderthal, and La Chapelle-aux-Saints, whereas the nasion of BSV2 was located anteriorly. The glabellar area of Sima de los Huesos 5 is higher than that of Biache-Saint-Vaast 2. The cranium of Petralona, which has a more curved glabellar area and a less raised frontal squama, differs the most from the other skulls compared.
The layout of the parietal-temporal profile of Biache-Saint-Vaast 2 is similar to that of Biache-Saint-Vaast 1. It was also found to be similar to that of Krapina 3 (after mirroring) up to the level of the temporal lines. The Amud 1 mastoid process is longer in this profile. The parietal bones of La Ferrassie 1, La Chapelle-aux-Saints, Monte Circeo 1, and La Quina H5 are more convex than that of BSV2; on the other hand, the parietal-temporal profile of Sima de los Huesos 5 is more vertical. Petralona yielded a very different profile, with a more oblique parietal bone.
The human fossil remains known as Biache-Saint-Vaast 2 show a set of plesiomorphic and apomorphic characteristics known to exist in late
As far as the frontal bone is concerned, the supraorbital torus of BSV2, which is of type III in Cunningham's system of classification (1908), resembles that present in the last European
The minimum frontal breadth of BSV2 is smaller than the mean Neanderthal value (
The sagittal profile of the frontal bone is similar to that of Krapina 3. The frontal squama (
The frontal torus has a vermiculate surface resembling that present in Neanderthal adults, as described by
The development of the frontal sinuses is comparable to that of the early and classic Neanderthals (
The maximum width corresponds to the infero-posterior third of the theoretical biparietal vault. The parietal bone does not look as robust as the Arago 47 and Petralona fossils. The parietal bone was found to be larger than that of the other fossils compared here but the osseous thickening between the superior and inferior temporal lines does not occur in the classic Neanderthal crania. The osseous thickening is relatively marked in the BSV2 parietal bone, more than in BSV1 (
Comparisons between the parietal-temporal profiles showed the existence of similar contours in BSV1 and BSV2 (
Anteroposteriorly, the temporal border of the parietal bone of BSV2 is short. Sima de los Huesos 5 has a relatively similar M30(1) chord. Among the Neanderthals, that of Saccopastore 1 is the most similar. The curvature of the temporal border is similar to the mean Neanderthal value, but the temporal borders of the latter fossils are longer. The maximum parietal breadth in BSV2 occurs at the level of the posterior third.
The temporal bone of BSV2 shows a set of characteristics, which are similar to those of the Neanderthals. The parietal notch has a similar layout (after inversion) to that of the right temporal bone of La Quina H27 (based on the layouts presented by
The mastoid process is small and rounded like that of Krapina 3, with a narrow digastric groove. In the posterior view, the mastoid process is directed medially, which contributes to giving it a rather rounded contour in the coronal plane, as observed with the Neanderthals, where it has been described as a full
As in the La Ferrassie 1, La Quina H5 and La Chapelle-aux-Saints skulls (
No anterior mastoid tubercle of the kind described in the La Chapelle-aux-Saints skull (
The digastric groove, the base of the styloid process and the stylomastoid foramen are not aligned, because the styloid process occurs more medially, as in Neanderthals (
In comparison with the articular fossae measured by
The mastoid crest in BSV2 goes backward and upwards toward the parietal incisures, parallel to the supramastoid crest, as described by
Applying the criteria adopted by
The values of the radii of the semicircular canals in BSV2 are similar to those of the Neanderthals, especially La Chapelle-aux-Saints and La Ferrassie 2 (
The three-dimensional model for the left bony labyrinth of BSV2 (
These anatomical comparisons have some limitations, however. Like many of the fossils discovered in isotopic levels 7 to 5 and found to resemble the Neanderthals (
Except for the osseous thickening observed between the superior and inferior temporal lines on the parietal bone, the characteristics of the cranial remains of Biache-Saint-Vaast 2 mainly resemble those of the early and classical Neanderthals (
The Middle Pleistocene site of Biache-Saint-Vaast contained fragments of 2 human crania. The fragmented fossil Biache-Saint-Vaast 2 (frontal and nasal bone, left parietal, temporal and sphenoid bones, and the occipital bone) were studied by combining conventional morphometric methods with a virtual rebuilding technique. Although this fossil is not a complete cranium, it shows a considerable number of anatomical similarities with the early and classic Neanderthals. These characteristics are: the pattern and development of the frontal sinus; the development of the supraorbital torus; a postero-superior depression of the parietal bone corresponding to a prelambdatic depression; the alignment of the zygomatic process with the external auditory meatus; a coronally orientated tympanic plate; non alignment of the digastric groove with the base of the styloid process and the stylomastoid foramen; the pattern and dimensions of the semicircular canals. The absence of a distinct anterior mastoid tubercle, the occurrence of osseous thickening between the superior and inferior temporal lines of the parietal bone suggest that these fossils may be members of the first European Neanderthal group.
Frontal bone of the Biache-Saint-Vaast 2 skull. Scale bar is 1 cm.
Os frontal de Biache-Saint-Vaast 2. Barre d’échelle de 1 cm.
Left parietal-temporal-sphenoid bones of Biache-Saint-Vaast 2. Scale bar is 1 cm.
Os pariétal, temporal, sphénoïde de Biache-Saint-Vaast 2. Barre d’échelle de 1 cm.
Occipital bone of Biache-Saint-Vaast 2. Superior view on the left and inferior view on the right. Scale bar is 1 cm.
Os occipital de Biache-Saint-Vaast 2. Vue supérieure à gauche, vue inférieure à droite. Barre d’échelle de 1 cm.
Frontal sinuses of Biache-Saint-Vaast 2 after virtual reconstruction.
Sinus frontaux de Biache-Saint-Vaast 2 après reconstruction virtuelle.
Frontal bone after virtual reconstruction and superimposition (white: before reconstruction).
Os frontal après reconstruction et superposition (blanc : avant reconstruction).
3-D positioning of the fragments of Biache-Saint-Vaast 2.
Positionnement spatial en 3-D de Biache-Saint-Vaast 2.
Pneumatisation of the petromastoid area and bony labyrinths of BSV2.
Pneumatisation de la région pétromastoïdienne et labyrinthe de Biache-Saint-Vaast 2.
Lateral and superior aspects of the left bony labyrinths of BSV2 reconstructed from sagittal CT scans. The lateral view is aligned with the plane of the lateral semicircular canal. Scale bar is 5 mm.
Aspect latéral et supérieur du labyrinthe de BSV2, reconstruit à partir de balayages sagittaux par rayonnement X. La vue latérale est alignée sur le plan du canal semicirculaire latéral. Barre d’échelle de 5 mm.
Comparison between the sagittal frontal profile of BSV 2 (red) and those of other European hominid fossils. The profiles are aligned on the basis of the Frankfurt plane and the nasion. Scale bar is 1 cm.
Comparaison des profils sagittaux frontaux de BSV2 (rouge) avec ceux d’autres hominidés fossiles d’Europe. Les profils sont alignés selon le plan de Francfort et le nasion. La barre d’échelle est de 1 cm.
Comparison between the parietal and temporal bone profile of BSV 2 (red) and those of other European hominid fossils. The profiles are aligned on the basis of the antero-inferior point of the mastoid process and the parietal notch. Scale bar is 1 cm.
Comparaison des profils de l’os temporal et pariétal de BSV2 (rouge), avec ceux d’autres hominidés fossiles d’Europe. Les profils sont alignés suivant l’extrémité antéro-inférieure du processus mastoïdien et l’incisure pariétale. La barre d’échelle est de 1 cm.
Measurements of frontal, parietal, temporal and occipital bones in mm.
Mesures des os frontaux, pariétaux, temporaux et occipitaux en mm.
Mean value between left and right sides.
Frontal sinus dimensions in mm.
Dimension des sinus frontaux en mm.
Bony labyrinth measurements.
Mesures des canaux semi-circulaires.