Saurichthys (Pisces, Actinopterygii) teeth from the Lower Triassic of Spitsbergen, with comments on their stable isotope composition ([delta] 13C and [delta] 18O) and X-ray microtomography

Abstract

A rich collection of exceptionally preserved Lower Triassic fossil fish remains obtained during the Polish Spitsbergen Expedition of 2005 includes many isolated teeth believed to belong to a saurichthyid actinopterygian. Stable isotope analysis (δ13C and δ18O) of putative Saurichthys teeth from the Hornsund area (South Spitsbergen) acting as a paleoenvironmental proxy has permitted trophic-level reconstruction and comparison with other Lower Triassic fish teeth from the same location. The broader range of δ13C values obtained for durophagous teeth of the hybodont selachian, Lissodus, probably reflects its migratory behaviour and perhaps a greater feeding diversity. X-ray microcomputed tomography (XMT), a non-destructive technique, is used for the first time in order to elucidate details of tooth histology, the results of which suggest that the method has considerable potential as a future analytical tool.