Teeth of actinopterygians from the Permo-Carboniferous of the Bohemian Massif with special reference to the teeth of Aeduellidae and Amblypteridae

Abstract

features characterizing species and also fundamentally indicating the individual’s way of life and food selection. The dentition varies considerably depending on the food type and foraging mode (Helfman et al. 2009). The marginal teeth of the maxilla, premaxilla and dentalosplenial can be distinguished from the teeth in the mouth cavity attached to the prearticular and coronoids of the lower jaw and the dermal bones of the palate of the upper jaw and variably on the ventral surface of the parasphenoid. The main function of marginal teeth is to capture and kill prey, retain prey in the mouth, and aid in swallowing. Marginal teeth show great morphological variation. They differ in their size, shape, number and spacing. It is also important to compare the size of the teeth with the size of the skull. Poplin & Heyler (1993) used as an illustration of this ratio a calculation of the tooth height compared to skull depth in front of the opercular series. The species studied in this contribution belong to the group of “primitive” actinopterygians which are characterized by the maxilla and premaxilla being firmly attached to the surrounding dermal bones. Together with the neurocranium, they form a firmly connected unit. Indications of a weakening of this firm connection are only visible in Aeduellidae where there is a regression of the posterior maxillary plate, almost vertical suspensorium and mosaic of small bones in the postorbital area. However, the upper jaw is still firmly attached to the surrounding dermal bones. Mouth open­ ing is activated by neurocranial elevation and a special mechanism for mandibular depression in all these “primitive” actinopterygians (Schaeffer & Rosen 1961; Lauder 1980, 1982). Schaeffer & Rosen (1961) assumed a fundamentally predaceous feeding mechanism in the “primitive” actinopterygians. Food items were probably caught by biting and swallowed in one piece with participation of the pharyngeal teeth. However, even in primitive actinopterygians, there is a great diversity among the marginal teeth. This diversity includes the probable original arrangement of teeth in two rows with big teeth in the medial row and more numerous smaller teeth in the lateral row (Poplin & Heyler 1993), teeth that are reduced to one row, or teeth that are specialized. Teeth on the dermal bones of the mouth cavity are also