Ichnology of Late Cretaceous echinoids from the Maastrichtian Type area (The Netherlands, Belgium) – 4. Shark versus echinoid: failed predation on the holasteroid Hemipneustes

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Hemipneustes striatoradiatus (Leske) is a medium- to large-sized (up to c. 115 mm in length) holasteroid sea urchin that is locally common in the upper Maastrichtian (Upper Cretaceous) of the type area of that stage in the south-east Netherlands and contiguous Belgium. Tests of this species were bored both in vivo and post-mortem, and encrusted post-mortem, but evidence of predation by vertebrates in the form of tooth marks is surprisingly rare. A peculiar specimen from the upper Nekum Member (Maastricht Formation) preserves two clusters of parallel grooves in trapezoid groups, and on opposite sides of the test. These are interpreted as evidence of failed predation, namely the bite marks of a marine carnivore with a fairly large mouth and closely spaced teeth with a pointed, conical cusp and, possibly, smaller cusplets. The most probable culprit was a non-durophagous shark such as a representative of the families Scyliorhinidae Gill or Squalidae Bonaparte, but certain types of teleost fish (aspidorhynchids, saurodontids or ichthyotringids) cannot be ruled out either.