A new thumb phalanx from Moula Guercy (France): description and considerations of Neandertal hand use

In this study we describe an adult left first pollical (thumb) proximal phalanx (I2-104) from the Baume de Moula-Guercy (Ardèche, France) and we evaluate its taxonomic status. We first describe this bone in detail, taking into account its pathology, before comparing it, through multivariate analyses, with a diverse sample of recent and fossil humans. Based on metric and morphological comparisons, we show that this phalanx belongs to a Neandertal individual who suffered from osteoarthritis. Osteoarthritis can have different origins, including overuse, degeneration, trauma and infection. Each of these possible etiologies is explored in our study. Although the cause is difficult to identify, the pathology in this individual may represent an inflammatory reaction caused by repeated and intense vibrations provoked by the high-frequency knapping of the left hand over time.