ŻYCIE I ŚMIERĆ PÓŹNOJURAJSKICH SKRZYPŁOCZY (XIPHOSURA) Z OWADOWA-BRZEZINEK W ŚWIETLE INTERDYSCYPLINARNYCH BADAŃ PALEOŚRODOWISKOWYCH

The horseshoe crabs (Xiphosura) are one of the most astonishing group in the animal kingdom. While only four species of the them have survived to the modern era, they appear relatively unchanged from the Ordovician (480 million years) and witnessed many mass extinction events, that justifies their nickname “living fossils” or “stabilomorphs”. This paper describes the discovery of new, well preserved Late Jurassic (Tithonian) horseshoe crabs from Owadow-Brzezinki quarry - one of the most important palaeontological sites in Poland, known from its exceptionally well-preserved fossils of marine and terrestrial biota. The discovery of many juvenile horseshoe crabs from the Owadow-Brzezinki Quarry a few years ago provided critical material for the studies of their paleobiology and paleoecology of their habitat. This paper concludes a number of studies that we have recently conducted, which add significantly to our knowledge of the group. Detailed examination of exceptionally preserved exoskeletons of the horseshoe crabs together with analysis of surrounding sediment allow to hypothesize about paleoenvironment of the site and seem to suggest the pathogenic algal infection as the most probable cause of mass mortality episode.