How shark teeth can decipher evolutionary processes

Abb. Tiger shark (© Dirk Krüßmann) Tooth shapes of the tiger shark: Already the embryo changes - and swallows - its teeth From embryo to turtle cracker: a team led by palaeobiologist Julia Türtscher from the University of Vienna studied the multiple changes in tooth shape in the tiger shark. The study, recently published in the Journal of Anatomy, is also central in drawing conclusions about extinct species from the myriad of preserved shark teeth in the field of palaeontology. Cartilaginous fishes, i.e. sharks, skates and rays possess a so-called revolver dentition: as soon as they lose a tooth, a new one follows, throughout their entire lives. "Accordingly, we have an incredible amount of teeth from both living and fossil cartilaginous fishes, which we can use to investigate when and how which species emerged or died out again," explains Julia Türtscher from the Department of Palaeontology at the University of Vienna. A particular challenge in this type of research is: In most shark species, the shape of the teeth changes over the course of their lives. Abb.