The Skull of Quadruped and Bipedal Vertebrates

Variations, Abnormalities and Joint Pathologies

Djillali Hadjouis

• Publisher: Wiley-ISTE
• Year: 2021
• ISBN:
  9781119832546
• Edition: 1
• Topic: Biological Sciences
• Subtopic: Evolution
• Index: Biological Sciences

This book forms part of the set, Comparative Anatomy and Posture of Animal and Human, and focuses on the skulls of Quaternary mammals and of Man since the acquisition of upright posture. Although the vast majority of the quadruped fossil species have a balanced postural adaptation, with no asymmetries or maxillo-mandibular dysmorphoses, the Hominine species that has acquired this readjustment of the body as well as a bipedal adaptation to the ground, will experience a series of postural imbalances starting with malocclusion in the genus Homo.

In order to arrive at this conclusion, the cranio-facial architectural biodynamics of several species of fossil and current mammals have been analyzed over three decades. In addition, hundreds of skulls of anatomically modern Hominids have been examined, highlighting their occlusal offsets, variations, anomalies and pathologies.

PART 1
The Skull of Fossil and Present-day Quadruped Vertebrates: Craniofacial Structure and Postural Balance

1
Proboscideans: The Mammoth (Mammuthus primigenius)

Super-Order Proboscidea.

Order Elephantoidea.

Family Elephantidae.

Genus Mammuthus Brooks, 1828.

Species Mammuthus primigenius Blumenbach, 1799 (woolly mammoth).

1.1. Chronological, geographical and morphological indications of the species

In the species of the Elephantidae Family, the orbits are very advanced on the antero-posterior axis of the skull and open in front of the jugal teeth; these are anatomical characteristics of animals without snouts. In general, in Mammals, the orbits open above the last molars (Lecointre and Le Guyader 2001).

The nose and upper lip are replaced by a flexible tube used for breathing, drinking, picking things up, etc. The lower canines are lost and the upper incisors are transformed into tusks that are continuously developing (Figure 1.1).

The species belongs to one of the three related genera regrouping mammoths and elephants (Mammuthus, Elephas and Loxodonta) included in the Family Elephantidae and classified in the Super-Order Proboscidea. These trunk bearers have provided no less than 170 fossil species, the oldest dating back 55 million years (Eocene). The first Elephantidae appeared in Africa 7 million years ago, the first mammoths 3–4 million years ago. Great confusion reigned for a long time among specialists for the classification of the mammoth and its origin. Today everyone is unanimous in classifying the first mammoths in Africa.

The arrival of mammoths in Europe and Asia took place around 2.6 million years ago. Three main Euro-Asian species followed one another. The southern mammoth (Mammuthus meridionalis), known in Saint-Vallier, Senèze and Chilhac, had a size exceeding 3 meters at the withers, large slightly curved tusks and jugal teeth whose hypsodontic character was still weak. The steppe mammoth (Mammuthus trogontherii), descendant of the previous one, was known in Sussenborn and Mosbach (Germany), in Abbeville and Saint-Acheul (France) and in Great Britain. With a height of more than 4 meters at the withers, this mammoth was considered the largest species in Europe. The woolly or Siberian mammoth (Mammuthus primigenius) is the best known. It appeared about 190,000 years ago and remains the most documented of all fossils due to the many discoveries of whole animals preserved in the permafrost (Guérin 1996a).

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Figure 1.1. Skull of a young present-day Asian elephant in left lateral view. Note the position of the orbits above the maxilla and not behind it (© Éditions Belin/Dominique Visset)

1.2. Mammoth discoveries in Île-de-France

The Fifth International Conference on Mammoths and their Families, held in 2010 in Le Puy-en-Velay, brought together the discoveries of this trunk fossil in more than 20 countries of Eurasia, Africa and America. Even though the Île-de-France region was not represented at this meeting, there have been a large number of remains of woolly mammoths in the departments of Hauts-de-Seine, Seine-Saint-Denis, Val-de-Marne, Yvelines, Essonne, Seine-et-Marne and Val-d’Oise, most of which were cleared during the 19th and 20th centuries as a result of quarrying on the outskirts of Paris. The latter also had its share of discoveries, sometimes complete skeletons, such as that of the Montholon Square near the Montmartre cemetery. In the department of Val-de-Marne, several bony and dental remains of woolly mammoths (M. primigenius) have been found since the end of the 19th century on the banks of the Seine and its confluence with the Marne (Ardouin et al. 2009; Hadjouis 2020a). Thanks to the land development of the last 40 years carried out along the river banks, preventive archeological operations have brought to light new discoveries in well-dated biostratigraphic contexts.

Although the remains of ancient mammoths and elephants unearthed in this small department of south-eastern Paris have been numerous (remains preserved at the Muséum national d’Histoire naturelle, Musée de Saint-Maur-des-Fossés and Musée d’antiquités nationales), most of them were transported and deposited on the banks of the Seine or in the loop of the Marne (Le Perreux, Nogent-sur-Marne, Saint-Maur-des-Fossés, Créteil, Valenton, etc.) without great chronostratigraphic precision.

Appearing in Eastern Siberia around 800,000 years ago, the woolly mammoth’s existence was known in Western Europe 200,000 years ago in chronocultural contexts of the Middle Paleolithic. With the exception of some spectacular specimens, it is mainly mandibles, cranial portions or isolated teeth that are found during archeological excavations or chance discoveries. Among the fossils recently dated by radiometric methods (uranium/thorium and carbon 14), two stand out: the young mammoth from Maisons-Alfort and the skull from Bonneuil-sur-Marne.

1.3. A young mammoth in Maisons-Alfort

The development operations of the Seine-Marne confluence, which began in the 1980s as part of the Seine-Amont project, have highlighted major sites such as Alfort 1 in Maisons-Alfort, located on the left bank of the Marne, a few hundred meters from its confluence with the Seine. One of the plots excavated in 1995 revealed a Neanderthal occupation of the Middle Paleolithic within the alluvial formations (Durbet et al. 1997). The association of identified animal species (aurochs, bison, red deer, Mosbach horse, wolf, mammoth) and the presence of a lith...