Een schedelafwijking bij Mammuthus primigenius (Blumenbach, 1799)

The article discusses a left half of a skull of Mammuthus primigenius (BLUM.), dredged from the river IJssel near Arnhem (51°59’ N.lat.- 6°06’ E.long.). It is remarkable for the obviously rare distortion of its incisor alveolus, the closest parallel to which is to be found in a mammoth skull from Russia, described by BRANDT (1871). The alveolus of the Dutch specimen is fractured by an accident that must have occurred in the animals youth. This resulted in the stunting of the growth of the immature tusk. If it was not lost because of an ensueing infection, it must have remained in the alveolus in a probably disfigured shape. Its largest diameter within the alveolus cannot have exceeded the ± 5 cm measured at the lower edge. The right tusk, as can be inferred from its fragmentarily preserved alveolar wall, reached normal dimensions (± 20 cm in diameter). A fragment of the injured tusk is still present in the Russian specimen, where its cross-section shows it to have been no more than half the size of the well developed one. Unfortunately, such evidence is lacking in the described skull fragment. A noticeable swelling of the bone tissue along the lower edge of the alveolus indicates an infection, but it may not have been decisive, since its inner surface is smooth.