Crossing the boundary: an elasmobranch fauna from S tevns K lint, D enmark

The chondrichthyan faunas from the D anish M aastrichtian chalk and the K / T boundary clay, the F iskeler, are described for the first time. The rich and diverse fauna discovered in the late M aastrichtian chalk experienced a massive drop in diversity prior to the boundary. However, the fauna started to recover immediately after the deposition of the impact layer during earliest D anian times and had regained much of its diversity during the first few millennia after the bolide impact. Precision sampling has made it possible to document the recovery of the fauna, which did not suffer an extinction event of the same magnitude, as apparently observed in M orocco. At S tevns K lint, only 33 per cent of the chondrichthyan fauna became extinct compared with the 96 per cent in M orocco. The drop in diversity before the boundary is attributed to a sudden change in sea level. Among the sharks found in the chalk and F iskeler are rare species such as P arasquatina and E chinorhinus and the first representative of N ebrius in E urope.