NeanderSTAN · Neandertal spine and thorax anatomy: 3D reconstruction, ontogeny and phylogeny

Neandertal spine and thorax anatomy: 3D reconstruction, ontogeny and phylogeny

There are many fundamental questions regarding the biology and energetics of Neandertals (Homo neanderthalensis) which remain unanswered. Was their locomotion different from that of our species, and if so, what were the energetic consequences? What was their standing posture like? How large was the Neandertal respiratory capacity? How was this capacity related to their energetic budget? These questions are fundamental to understand this extinct species' biology. In this research project we plan to obtain important insights from the study of the morphology, the ontogeny, and the phylogeny of the vertebral column (VC) and the thorax (TH) of Neandertals using traditional morphometrics and Virtual Anthropology (VA) techniques. The study of vertebrae and ribs in human evolution is relatively scarce and no serious attempt of using VA techniques has been so far attempted. Human VC and TH morphology are instrumental in the efficient weight transmission and balance of the torso that, together with the unique morphology of the human pelvis and lower limb, make their bipedal gait possible. When compared to the great apes, we show an exclusive morphology of the spine with three presacral curvatures, a VC located more ventrally (invaginated) inside the TH, a long lumbar region and relatively large vertebral bodies that support the weight of the upper body weight. TH size is related to lung size and TH shape is related to the mobility of the pectoral girdle and upper limb. The VC protects the spinal cord and bony spinal canal is highly correlated with spinal cord size. An increase in the size of the vertebral bony canal has been found during human evolution. However its potential relationship to the increase in encephalisation (relatively larger brains compared to body size) that occurred during the Pleistocene, especially in the Middle Pleistocene has not been studied. In sum, the morphology of the vertebral column (VC) and thorax (TH) provide important information regarding the biomechanics and physiology of humans and their study can provide important insights into the evolution of fossil hominins and our own species. In this project we will focus on the VC and TH of Neandertals. To accomplish this, 1) the vertebrae and ribs of a large sample of Neandertal adult specimens will be analyzed individually; 2) the VC and TH of a Neandertal (Kebara 2) will be virtually reconstructed in order to gain insights into the overall anatomy; 3) vertebrae and ribs of immature Neandertal individuals will be studied in order to gain insights into the ontogeny of the Neandertal TH and VC; and 4) vertebrae and ribs from the Middle and Lower Pleistocene will be studied in order to assess the evolution of these two anatomical regions in the Neandertals and in our own lineage. This holistic approach will provide unique information regarding biomechanics, posture, paleophysiology and ecogeographical patterning that will help to understand the biology of Neandertals. This project is part of a longer-term research project that aims to understand the changes in the VC and TH in the hominin lineage. This project took place within the UMR 7194 of the CNRS at the Muséum national d’Histoire naturelle (MNHN, Paris) under the supervision of Dr. Antoine Balzeau and with close collaboration with Dr. B. Maureille from the UMR 5199 (Bordeaux, France) as well as with other important international researchers such as Dr. Ella Been. During this project the work that has been carried out included: -the learning of virtual anthropology software -the revision of faunal remains of different sites in order to find new vertebral and costal remains -the metric and morphological study of unpublished Neandertal material -The micro-ct scanning of unpublished Neandertal remains -The virtual reconstruction of Neandertal vertebrae and ribs -Participation in the excavation and lab work on the Atapuerca sites that preserve the most extraordinary human fossil record yet discovered -The tutoring of a master student that has worked on the covariation between the cervical morphology and the head in order to try to explain the peculiarity of the Neandertal cervical morphology. -Dissemination work included master and department seminars as well the preparation of scientific papers, some of which have been already submitted, and others are about to be finished. During the development of the present project there are different important results that have been achieved: -The finding of new hominin costal and vertebral remains remains that will help us to understand the evolution of these two anatomical region. These new remains belong to three different human species: Homo antecessor (Lower Pleistocene), Homo heidelbergensis (Middle Pleistocene) and Homo neanderthalensis (Late Pleistocene) -The description for the first time of fossils that are providing an exact idea of the Neandertal vertebral column and thorax morphology, which is significantly different from that of modern humans both at the scale of the individual elements. -The 3D reconstruction for the first time of a complete Neandertal spine and thorax which is providing new insights at the organismal level. Thanks to this reconstruction we have detected for the first time that Neandertals had a more invaginated vertebral column which would likely compensate for the low degree of lordosis present in the lumbar spine. The expected final results of this project are not only going to be published in specialized and generalized high impact scientific journals but also, within a more evolutionary scope, as a book chapter in a book called Neandertal Skeletal Anatomy that will be published by Cambridge University Press, which is a book destined to become a classic. Here all the minute detail descriptions provided in specialized journals will crystalize in a change of paradigm in which it will recognized the vertebral column and thorax of Neandertals as an anatomical region with distinct morphology from that of modern humans.

Data: CORDIS, © European Union