Phyllodont tooth plates of Bobasatrania scutata (GERVAIS, 1852) (Actinoperygii, Bobasatraniiformes) from the Middle Triassic (Longobardian) Grenzbonebed of southern Germany and eastern France, with an overview of Triassic and Palaeozoic phyllodont tooth plates

摘要

Phyllodont tooth plates from the Longobardian Grenzbonebed of southern Germany known for more than 170 years are described in detail for the first time. They consist of up to eight layers of superimposed rounded to conical teeth, each layer with up to 300 teeth. An upper and a lower tooth plate can be differentiated with different outlines and reliefs of the chewing surface. Identical dentitions have been described by GERVAIS (1852) under the names Colobodus scutatus (upper tooth plate) and C. hogardi (lower tooth plate) from the uppermost Muschelkalk of Lorraine, France. The superposition of the teeth and the missing of a wart on top of the teeth support the transfer of C. scutatus to the genus Bobasatrania known by complete skeletons with phyllodont tooth plates from the Early Triassic of Madagascar, Greenland and further localities. Bobasatrania scutata represents the youngest record of the genus. The tooth plates are best documented of all Bobasatrania dentitions and are compared with all known Early Mesozoic and Late Palaeozoic phyllodont tooth plates. An up to now unmentioned record of a Bobasatrania tooth plate from the Early Triassic of the Salt Range, Pakistan, is described. The tooth plates of Bobasatrania act as a tongue-bite apparatus known from osteoglossomorph fishes.