Jurassic fish choking on floating belemnites

Abstract

Abstract Tharsis, an extinct genus of ray-finned fish (Actinopterygii) in the Late Jurassic, has but tiny teeth and is considered a micro-carnivore/visual zooplanktivore. A recent review of collection material, however, uncovered several specimens of Tharsis from the Late Jurassic (ca. 152 Ma) Plattenkalk deposits of the Solnhofen Archipelago with belemnites wedged in mouth and gill apparatus. In all cases, the rostrum reexits through the gill apparatus, whereas the broad phragmocone of the belemnite is firmly lodged in the mouth opening. Apparently, these micro-carnivore fish were in the habit of sucking remnants of decaying soft tissue or overgrowth such as algae or bacterial growth from floating objects, but when a streamlined floating belemnite rostrum accidentally was sucked into the mouth, they were no longer able to get rid of these deadly objects.