Friday, 20 August 2021

Neanderthal timeline 1: 1829 Engis 2.

The Engis 2 partial cranium was discovered in 1829 by the Dutch physician and naturalist Philippe-Charles Schmerling in the lower of the two Awirs Caves. As Schmerling approached the caves over the Plateau des Fagne, from the village of Engis, he naturally christened them the Grottes d'Engis.


The Awirs valley today, the location of the the Engis 2 cave is not shown as it collapsed in 1993. Photo credit 27 Crags (2017)

These have since become known as the Grottes d'Engis or Schmerling Caves. Schmerling himself, named the caves for Engis because he accessed them from the Plateau des Fagnes, which is in the Engis commune, above the cavities. Schmerling (1833-34) gives a detailed, first-hand account:

From his section II Engis Caves: “Three quarters of a league northwest of Chokier is the place known as the Awirs, located north behind the village Engis. Vis-à-vis a former exploitation of aluminous shale, is a very steep limestone hill, filled with crevices and openings, two of which are on the upper part of this perpendicular cliff; but we see them without being able to reach them from this side. We were therefore obliged to take a means of examining these cavities more closely. Using a rope, attached above to a tree, we were able to slide obliquely towards the foot of a first opening. A small path stretches out at some distance, formed by the rock which advances enough to be walked along. Grass and shrubs have multiplied spontaneously on the sterile rock: they hide in some places the precipice that one has in front of you.

The first cavity is 5 meters wide and 6 high at the entrance the total depth of this cavity is 17 meters: towards the end the vault is lowered more and more. The bottom, in the posterior part, is little covered with earth; a small gallery exists on the right, and it is parallel to the main opening. The bone earth, which presented the same characteristics as that of the other caves, was very abundant on the interior part, where it was 2 meters thick; but towards the posterior part, and in the small side gallery, there were few.

The treasures collected in this cave are: An incisor tooth, a dorsal vertebra and a male phalanx, some remains of bears, hyenas, horses, and ruminants; several flint sizes in triangular shape. By clinging to the walls of the rock, we descend from this first opening to a second, after having passed over a point of the rock, along a small path, 17 meters long. The entrance to this cave is 5 meters high and 4 meters wide; like the previous one, it has a view of the North. It is located one meter below the level of the first; near the beginning of the school year are many shrubs which have grown naturally in the bone earth. The depth of the first chamber, which is the main one, is 12 meters, over a height of 5 and a width of 4m near the entrance is a singular separation, formed by the limestone which passes in a straight line; in this place the cave is cut in two, in the form of an arcade. At the end of this room there is a not very wide gallery which descends to the left, so that it describes a semi-circle, always lowering itself; it is filled with earth containing bones. Soon we find ourselves stopped by the little space offered by this corridor, which ends with a small opening in which we cannot enter. On the left side of the main opening there is a second gallery, which is difficult to reach because of the very slippery stalactites which are at the height of a meter and a half. After crossing this vertical entrance, you find yourself on the limestone bench which goes almost parallel to the entrance. We see on the right an opening which leads in the opposite direction into a small gallery, the floor of which rises towards the south, and at the top of which is a small chamber whose bed was strewn with bones. In addition to the stalactites which are in this cave, one meets in the principal chamber a bony breccia; it is placed near the gallery which is at the back; we will speak of it in more detail in the description of human bones.

The bones of this cave were in general very dry, having the same characters as that of the other localities; it had on the rising, a thickness of two meters and a half, and contained bones and stones rounded and angular throughout its height; it covered in the lower part a clayey ground more or less compact, resting on the bottom formed by the rock, which is everywhere very uneven.

The bones coming from this cave have, in general, a yellowish-white tint, which varies to blackish and have been rolled for some time before being dropped off in the place where we collected them. It was from this cave, among other things, that I removed bones of bears, hyenas, and several rhinoceroses, etc., which showed me that these bones could only have been deposited there by water. Finally, on the right, entering the second cave, is a gallery which is only a continuation of the limestone which extends under a vault in this place, and which leads into another gallery, the longest of all, having little height and width. Both have provided me with bones lying in the same soil than that of the neighbouring caves, but less numerous than in the second that we have just described.”

In section IV, ‘Human Fossil Bones in Particular’, Schmerling recounts:

“Human bones are too well known for me to need to enter into a detailed description of these remains. It is more important not to neglect anything with regard to their deposit, and first of all I observe that these human remains, which are in my possession, are, like the thousands of bones that I have recently unearthed, characterized by their degree of decomposition, which is absolutely the same as those of extinct species; all are broken, with a few exceptions; some are rounded, as often occurs in the fossil bones of other species. The breaks are vertical, or oblique, none showing traces of erosion, the colour does not differ from that of other fossil bones, and varies from yellowish-white to blackish. All are lighter than normal bones, with the exception of those which are covered with a layer of calcareous tuff, or whose cavities are filled with such concretions.

The skull which I had represented, plate I, fig. 1-2, is from an elderly individual. The sutures begin to fade, all the facial bones are missing, and only a fragment of the temporal bone on the right side has been preserved.

The face and the base of this skull were removed, before it was deposited in this place since after having regularly exploited all this cave, we could not find these remains. It was a meter and a half deep that we encountered this skull, hidden under a bony breccia, made up of the remains of small animals, and containing a rhinoceros tooth, and some of horse and ruminants. This breccia, of which we have spoken, p. 31, was a meter wide, rising a meter and a half above the floor of the cave, and adhering strongly to the wall.

The earth, which contained this human skull, indicated no disturbance; rhinoceros, horse, hyena and bear teeth surrounded him on all sides.

The famous Blumenbach (1) exposed the differences in the shape and dimensions of human skulls of different races. This important work would have been of great help to us if the face, an essential part in determining race with more or less certainty, were not lacking in our fossil skull. We are convinced that, from a single sample, we cannot at all say with certainty, even if this head would be complete, because the individual shades are so numerous in the skulls of the same race, that one cannot without to expose oneself to the greatest consequences, to conclude from a single fragment of the skull for the total shape of this head.

(1) Decas Colleclionis suae craniorum diversarum genliitm illustrala, Gotùngae, 1793- 1820.

However, not to neglect anything concerning the shape of the skull fossil that we have collected, we will observe that the form elongated and narrow forehead first fixed our attention.

Indeed, the little elevation of the frontal, its narrowness and the shape of the eye sockets, bring it closer to the skull of the Ethiopian than to that of the European, the elongated shape, and the developed state of the occiput, are still characters which we believe to have noticed in our fossil skull, but to avoid any doubt in this regard, I have made represent the outline of the skull of a European, and of an Ethiopian, and the fronts shown on plate II, fig. 1, i, same plate, fig. 3 and 4, will be enough to distinguish the differences, and a single glance at these figures will say more than a long and boring description.

Whatever judgment we make on the origin of the individual where this fossil skull comes from, we can, it seems to us, express our opinion without exposing ourselves to a controversy, the outcome of which would be without positive result.

Each one, moreover, is free to choose the hypothesis which seems to him the most founded; as for me, it is shown to me that this skull belonged to an individual whose intellectual means were not very developed, and we conclude that it comes from a man whose degree of civilization was not to be very advanced this which we can realize by comparing the capacity of the forehead with the occipital part.

Another skull, of a young individual, was on the bottom of this cave, next to an elephant tooth; this skull was whole until the moment when I wanted to collect it, it then fell to pieces that, I have not, as yet, been able to put it together again. But I have represented the bones of the upper jaw, plate I, fig. 5. The state of the alveoli and teeth shows us that the molars had not yet pierced the gums. Detached milk molars, and some fragments of human skull come from this same place.

Figure 3 shows a human upper incisor tooth, which, by its size, is truly remarkable.

Figure 4; is a fragment of the upper jaw bone, the molar teeth of which are worn down to the root.

I have two vertebrae, a first and a last dorsal.

A clavicle on the left side, (see plate III, figure 1); although having belonged to a young individual, this bone announces the rather large size of this individual.

Two fragments of radius, badly preserved, do not indicate to me that they belonged to an individual whose dimensions exceeded the height of the man, being five and a half feet.

As for the remains of the upper extremities, those in my possession are limited to a fragment of ulna and radius. (plate III, fig. 5 and 6.)

Figure i of plate IV, represents a bone of the pastern, contained in the breccia we have spoken of; it was in the lower part, above the skull; add to this a few bones of the pastern, drawn from very different distances, half a dozen metatarsals, three phalanges of the hand and one of the foot. Here is the succinct enumeration of the remains of human bones collected in the cave of Engis, which has preserved for us the remains of three individuals, surrounded by those of the elephant, the rhinoceros, and predators of species unknown in the present creation.”


Human fossils from the lower Engis Cave. All except Fig. 5 were from modern humans, the maxilla, however belonged to the infant Neanderthal, whose skull is known as Engis 2. image credit: Schmerling (1833-4) via Orbi (2021).

Lastly, Schmerling, also realised that, the flint objects found in association with human and animal bones were actually man-made.

Schmerling’s publication of his finds, with its lucid writing and huge number of beautifully drawn plates provided a catalyst for further debate on the antiquity of man. Such luminaries as Geoffroy St. Hilaire, William Buckland, Charles Lyell and others visited Schmerling and examined his fossil collection.

Huxley (1863) in his book, Evidence as to Man's place in Nature, has a chapter entitled “On Some Fossil Remains of Man”. Here he compared the Engis I skull (Figs. 1 an 2 above) with the skull from Kleine Feldhofer Grotte in the Neandertal valley. He compared the two skulls, then compared them to the various ‘races’ of man. He explores the shape of the face, the dimensions of the various skulls, their development of the supraciliary ridges a, from such populations as Australians, Tartars, Danish, Negros, Calmucks (Mongolians) and “and of a well developed round skull from a cemetery in Constantinople, of uncertain race, in my own possession”. He also compared cranial capacities, where available. In conclusion he writes:

“But taking the evidence as it stands, and turning first to the Engis skull, I confess I can find no character in the remains of that cranium which, if it were a recent skull, would give any trustworthy clue as to the Race to which it might appertain. Its contours and measurements agree very well with those of some Australian skulls which I have examined—and especially has it a tendency towards that occipital flattening, to the great extent of which, in some Australian skulls, I have alluded. But all Australian skulls do not present this flattening, and the supraciliary ridge of the Engis skull is quite unlike that of the typical Australians.

On the other hand, its measurements agree equally well with those of some European skulls. And assuredly, there is no mark of degradation about any part of its structure. It is, in fact, a fair average human skull, which might have belonged to a philosopher, or might have contained the thoughtless brains of a savage.

The case of the Neanderthal skull is very different. Under whatever aspect we view this cranium, whether we regard its vertical depression, the enormous thickness of its supraciliary ridges, its sloped occiput, or its long and straight squamosal suture, we meet with ape-like characters, stamping it as the most pithecoid of human crania yet discovered…

In no sense, then, can the Neanderthal bones be regarded as the remains of a human being intermediate between Men and Apes. At most, they demonstrate the existence of a man whose skull may be said to revert somewhat towards the pithecoid type...

And indeed, though truly the most pithecoid of known human skulls, the Neanderthal cranium is by no means so isolated as it appears to be at first, but forms, in reality, the extreme term of a series leading gradually from it to the highest and best developed of human crania. On the one hand, it is closely approached by the flattened Australian skulls, of which I have spoken, from which other Australian forms lead us gradually up to skulls having very much the type of the Engis cranium. And, on the other hand, it is even more closely affined to the skulls of certain ancient people who inhabited Denmark during the 'stone period'..

The correspondence between the longitudinal contour of the Neanderthal skull and that of some of those skulls from the tumuli at Borreby, very accurate drawings of which have been made by Mr. Busk, is very close. The occiput is quite as retreating, the supraciliary ridges are nearly as prominent, and the skull is as low. Furthermore, the Borreby skull resembles the Neanderthal form more closely than any of the Australian skulls do, by the much more rapid retrocession of the forehead. On the other hand, the Borreby skulls are all somewhat broader, in proportion to their length, than the Neanderthal skull, while some attain that proportion of breadth to length (80:100) which constitutes brachycephaly.

In conclusion, I may say, that 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. And considering what is now known of the most ancient races of men; seeing that they fashioned flint axes and flint knives and bone-skewers, of much the same pattern as those fabricated by the lowest savages at the present day, and that we have every reason to believe the habits and modes of living of such people to have remained the same from the time of the Mammoth and the tichorhine Rhinoceros till now, I do not know that this result is other than might be expected.

Where, then, must we look for primaeval Man? Was the oldest 'Homo sapiens' pliocene or miocene, or yet more ancient? In still older strata do the fossilized bones of an Ape more anthropoid, or a Man more pithecoid, than any yet known await the researches of some unborn palaeontologist?

Time will show. But, in the meanwhile, if any form of the doctrine of progressive development is correct, we must extend by long epochs the most liberal estimate that has yet been made of the antiquity of Man.”

Despite the fact that Huxley was a diligent and thoughtful scientific investigator, by the standards of his day, there is a double irony attaching to his assessments of the fossils he chose to discuss.

Firstly, less than a year later, King (1864a and b), published his assessment of the Kleine Feldhofer Grotte cranium as a new species, namely Homo neanderthalensis. Secondly, the other skull collected at lower Awirs cave was, although juvenile, actually a Neanderthal too. So near, but so far in terms of your name living on in scientific posterity!

A diagnosis of the Engis 2 cranium as a Neanderthal would not be written until, over a century later, by Fraipont, (1936). The lower of the Engis caves was investigated by numerous excavators over the next 125 years. These included  archaeological investigations: in 1868 by the geologist Éd. Dupont, in 1885 by the palaeontologist J. Fraipont, then by other people such as É. Doudou from 1895 onward and J. Hamal-Nandrin in 1904; finally, over the 20th century, by teams from the 'Chercheurs de la Wallonie' association, notably in 1907 and 1956.

Although, the Engis 2 cranium had been assigned to Homo Neanderthalensis early in the 20th century, Tillier (1983) provided a modern analysis. She concludes her study of the Engis 2 cranium thus:

“During our study we compared the metric and morphological data of the skull of Engis 2 with those of other Neanderthal children and with those of a sample of current skulls whose dental age was between 5 and 10 years. Some initial remarks can be made regarding the development of the Neanderthal skull.

Among the dimensional characteristics of the skull of Engis 2 which deviate from the data collected on current subjects we can retain the frontal width and the interorbital width the biporic width, and the biasteric width, the maximum width of the skull: all these measurements are large on Engis 2 while the bimastoid width, for example, remains close to the current average value. In addition to these dimensions, the lambdoid parietal curvature index and the sagittal occipital curvature index are lower on Engis 2.

Certain metric characters of the skull of Engis 2 contrast with the data known in Neanderthal adults. Thus the bregmatic and frontal Schwalbe angles, the sagittal parietal curvature index are placed outside the variation limits for adults. Such an arrangement is found for the frontal on the Teshik-Tash skull while the sagittal parietal curvature index corresponds to the lower limit of adult Neanderthal variation. On the temporal on the other hand, the height / length index of the scale and that giving an idea of ​​the development of the mastoid process in relation to the length of the scale distance Engis 2 from Neanderthal adults and bring it closer to current children.

Most of the derived morphological characters retained on the skull of the adult Neanderthal are already recognizable in the child of Engis 2. as shown by the parietal. the occipital and the temporal. The morphology of the maxillo-malar region in extension can be considered without being demonstrated (in the absence of bone support); the study of the maxilla of Gibraltar 2 (Tillier 1982) found on the other hand, that the development of maxillo-malar angulation could be variable.

Some characters, in relation to the young age of the subject, are only sketched out on Engis 2, such as the suporbital torus, the separation of the petrotympanic crest and the mastoid process, or absent such as certain occipital temporal reliefs and frontal pneumatization.

Finally, other characters, present on Engis 2, have no significant value from a phylogenetic point of view, such as the relative development of the posterior zygomatic tubercle, the great width of the digastric groove or the small size of the teeth (except of dc M1 and dm2).

The attribution of the skull of Engis 2 to the group of Neanderthals cannot therefore be called into question. He represents with the men of Spy, with whom he shares certain characteristics such as the width of the digastric groove and the relative development of the posterior zygomatic tubercle (Spy I) or the single suprasiniac fossa (Spy 2), the best-known representatives of this evolutionary morphological stage in Belgium. Engis 2 also constitutes a reference element in the ontogenetic study of the Neanderthals, the importance of which can no longer be neglected.”


Tillier (1983) showing the principle frontal sutures. Original caption reads: Norma frontalis of the skull of Engis 2 showing the outline of the supraorbital torus.


Rear view of the occipital region of Engis 2 showing the spreading of the supra-iniac fossa and the insertion of large complexus [broad muscle lying along the back part of the neck, connecting the occiput and the lower cervical and upper dorsal vertebræ].. From Tillier (1983).

The dates for the Engis 2, Neanderthal infant have been somewhat contentious. Toussaint and Pirson (2006) obtained dates of ca. 26,820 and 30,460 BP on cranial fragments. These are regarded as too young.

Even the author [Toussaint (2011)] comments: “As for chronostratigraphy, the only information available comes from radiocarbon dating. Two contiguous fragments of the left parietal of the Neanderthal child thus provided two dates (Toussaint & Pirson, 2006a). The first, 26,820 ± 340 B.P. (OxA- 8827; delta 13C = -19.3), is far too recent in view of the regional and north-western European context to be acceptable. Even the second, 30,460 ± 210 B.P. (GrA-21545), hardly makes sense in the archaeological context from the Bassinmosan where such a date is more in phase with a fairly old Aurignacian.”

Devièse et al. (2021) finally achieved more reasonable dates for Engis 2. The researchers took collagen samples from Neanderthal skeletal remains originally found in 1829.

While taking collagen samples for radiocarbon dating is a standard technique used to date fossils, the researchers had to use an advanced purification method Using liquid chromatography in order to separate the collagen samples from all contaminants. They found that the contaminants arising from the actual methods of preservation themselves, including glue prepared from bovine bones used to preserve skeletal remains had affected the radiocarbon dates, making them appear too young.

Using this process, the researchers were able to isolate just one molecule — a single amino acid — in order to increase the accuracy of the radiocarbon date read.

Based on these new radiocarbon dates, the authors of the study estimate that the Neanderthal child, Engis 2, dates to between 40,600 and 44,200 years ago. 

Other parts of the Engis assemblage have also provided a greater depth of understanding, in terms of Neanderthal child development. In particular, the partial mandible found, and illustrated by Schmerling (1833-34) has been studied in depth.


The Engis partial mandible found by Schmerling from Parg, (2015).

Futher research has included an ontogenetic analysis was carried out by Smith et al. (2010). In this very illuminating study, a new age at death was calculated for the Engis 2 Neanderthal child, using the unerupted teeth in the mandible recovered from the lower Engis cave. The authors explain the variables they measured and how these result in an accurate age at death, they stated: “To calculate crown formation time, molar eruption age, and age at death, we quantified the following standard developmental variables: cuspal enamel thickness, long-period line periodicity (number of daily increments between successive long-period lines), total number of long-period lines in enamel (Retzius lines or perikymata), and coronal extension rate (speed at which enamel forming cells are activated to begin secretion along the enamel-dentine junction) in 90 permanent teeth from 28 Neanderthals and 39 permanent teeth from 9 fossil H. sapiens individuals…

Combining histological data on initiation ages, crown formation times, and root formation times yields age-at-death estimates for six Neanderthal and two fossil H. sapiens juveniles.” They arrived at an age of 3.0 years for the Engis 2 Neanderthal, individual, at death. 


Scan of the Engis 2 maxilla, showing unerupted permanent incisors and canines, from Smith et al. (2010). Original caption reads: Fig. 1. Virtual histology of the maxillary dentition from the 3-y-old Engis 2 Neanderthal. (A) Synchrotron micro-CT scan (31.3-μm voxel size) showing central incisors in light blue, lateral incisors in yellow, canines in pink, and third premolars in green. (Deciduous elements are not rendered in color as they were not studied.). Scale bars in A and B, 10 mm.

To this day the Engis 2, cranium of the Neaderthal child justly, fascinates archaeologists and palaeoanthropologists and the public alike. It is a poignant relic of a life cut brutally, short. I wonder what the youngster thought and felt in the months leading up to their untimely demise? Did they play along the banks of the Awirs stream below and was it some chance accident or disease, that brought about their death? Did their parents bury them in the cave with as much grief as a modern family would have? These are the unanswerable questions that haunt me.


Engis 2 virtual reconstruction by John Hawks (2021) – I wonder what he or she looked, in the flesh?

References

27 Crags (2017). At: https://27crags.com/crags/awirs/photos accessed 19/08/2021

Devièse, T., Abrams, G., Hajdinjak, M., Pirson, S., De Groote, I., Di Modica, K., Toussaint, M., Fischer, V., Comeskey, D., Spindler, L. and Meyer, M., 2021. Reevaluating the timing of Neanderthal disappearance in Northwest Europe. Proceedings of the National Academy of Sciences, 118(12).

Fraipont, C. (1936) Les hommes fossiles d'Engis. Archives de l'institut de Paléontologie Humaine. Memoire, 16: 52 p.

Hawks, J. (2021). Neanderthals. At: https://twitter.com/johnhawks/status/1367226871948185603 accessed 18/08/2021

Huxley T. H. (1863). On Some Fossil Remains of Man, in Evidence as to Man's place in nature. Williams & Norgate, London.

King, W. (1864a). On the Neanderthal Skull, or Reasons for believing it to belong to the Clydian Period, and to be a species different from that represented by Man, Report of the British Association for the Advancement of Science. London. 33rd Meeting (1863), p81-82

King, W. (1864b). The reputed fossil man of the Neanderthal. Longmans Green & Company.

Orbi (2021). Recherches sur les ossemens fossiles découverts dans les cavernes de la province de Liège. Down load at:  https://orbi.uliege.be/handle/2268/207986 accessed 17/08/2021

Parg, P. (2015). Engis 2 Maxilla. At: https://commons.wikimedia.org/wiki/File:Engis_2_Maxilla.jpg accessed 18/08/2021

Schmerling P.-C. (1833-34) – Recherches sur les ossemens fossiles découverts dans les cavernes de la province de Liège, P.-J. Collardin, Liège, 2 tomes de 167 et 195 p.

Smith, T.M., Tafforeau, P., Reid, D.J., Pouech, J., Lazzari, V., Zermeno, J.P., Guatelli-Steinberg, D., Olejniczak, A.J., Hoffman, A., Radovčić, J. and Makaremi, M. (2010). Dental evidence for ontogenetic differences between modern humans and Neanderthals. Proceedings of the National Academy of Sciences, 107(49), pp.20923-20928.

Tillier,  A.-M. (1983) Le crâne d'enfant d'Engis 2: un exemple de distribution des caractères juvéniles, primitifs et néanderthaliens. Bull. Soc. roy. belge Anthrop. Préhist., 94 :51-75.

Toussaint M. and Pirson S. (2006). Neandertal Studies in Belgium : 2000-2005. Periodicum Biologorum, 108: 373-387.

Toussaint, M., Semal, P. and Pirson, S. (2011). Les Néandertaliens du bassin mosan belge: bilan 2006-2011. Le Paléolithique moyen en Belgique, pp.149-196.


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