The predation upon, and the extinction of, the latest Maastrichtian populations of the ammonite species Hoploscaphites constrictus (J. SOWERBY, 1817) from the Middle Vistula Valley, Central Poland

Abstract

The usually paired punctures piercing the shells of the ammonite species Hoploscaphites constrictus (J. SOWERBY, 1817) throughout, and stated in specimens coming from the latest Maastrichtian siliceous-chalk sequence of Nasiłów near Kazimierz-on-Vistula in the Middle Vistula Valley, Central Poland, are interpreted as a result of predatory attacks of the crabs upon the emptied shells. Such attacks are thus recognized as unsuccessful for the crabs which have given up a further damage of the come-acrossed ammonite shells when having felt them empty. The successful attacks realized in a complete crushing of the ammonite shells, the hashed fragments of which remained dispersed over the seafloor litter. Based on the foregoing, discussed is the relation of the crabs’ attacks to the mortality and, consequently, to the extinction of this ammonite species by the Late Cretaceous decline. Finally, a bearing of the latter on the discussion upon the terrestrial causes of the K/T bioevolutionary turnover is also outlined.