The dentition of the enigmatic pycnodont fish, Athrodon wittei (Fricke, 1876) (Neopterygii, Pycnodontiformes; Late Jurassic; NW Germany)

Most pycnodontiform fishes are represented by their distinctive dentition alone, whereas articulated skeletons are very rare and the systematic position of most taxa based upon isolated teeth and the association of upper and lower dentitions to a specific taxon is still somewhat ambiguous in most cases. The vomerine dentition of the Late Jurassic pycnodontiform Athrodon wittei (Fricke, 1876), which is described here for the first time, is characterised by a high number of lateral tooth rows and the distinct morphology of the teeth. The dentition of Athrodon differs from most other pycnodont dentitions in the peculiar arrangement of the teeth into irregular rows and not well-differentiated principal row. The absence of regular tooth rows is not considered plesiomorphic here but most probably was achieved independently in different pycnodont lineages. The high number of lateral tooth rows (> four) is considered to be autapomorphic for Athrodon. The pycnodont fish Nonaphalagodus from the Albian of Texas, which also is known by isolated dentitions only, resembles Athrodon in the high number of vomerine tooth rows but differs in that this taxon displays the more derived feature of the teeth being arranged more regularly and individualized rows. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)