New Research Uncovers Bizarre Fatal Interactions of Jurassic Fish

A recent study has shed light on the peculiar demise of an extinct genus of ray-finned fish known as Tharsis, which thrived during the Jurassic period. The research, conducted by paleontologists Martin Ebert and Martina Kölbl-Ebert from Ludwig Maximilian University of Munich, reveals that these fish frequently met an untimely end due to large cephalopods, specifically belemnites, lodged in their throats. The findings were published in the journal *Scientific Reports* on July 13, 2025.

The fossilized remains of Tharsis fish, discovered in the 152 million-year-old Solnhofen Plattenkalk formation in Germany, indicate that these marine creatures were often found with belemnites stuck in their mouths. According to the study, the belemnite rostrum, or beak, would protrude through the fish's gill apparatus while the phragmocone, its internal shell, remained trapped inside the mouth. This suggests a catastrophic feeding error rather than predation, as Tharsis were micro-carnivores that primarily consumed small organisms such as zooplankton using suction feeding techniques.

Ebert and Kölbl-Ebert note in their paper, "A recent review of collection material uncovered several specimens of Tharsis from the Late Jurassic 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."

The belemnites, resembling squid with elongated bodies and multiple appendages, were less frequently fossilized compared to Tharsis fish. The researchers propose that the belemnites found in these deposits often had their internal shells overgrown with bivalves, indicating they were dead and buoyant in the water column, likely drifting before encountering the Tharsis fish.

The study posits that Tharsis fish were not actively hunting belemnites; rather, they may have been attempting to feed on decaying organic material or algae present on floating objects. When a belemnite's rostrum was inadvertently ingested, the fish could not expel it through their gills, leading to suffocation and death. Ebert and Kölbl-Ebert emphasize, "Apparently, these micro-carnivore fish were in the habit of sucking remnants of decaying soft tissue or overgrowth 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."

This research not only contributes to the understanding of Jurassic marine ecosystems but also highlights the complex interactions between species during that period. Future studies may further explore the feeding behaviors and ecological roles of Tharsis fish and their contemporaries within the Solnhofen formation. The implications of such findings extend to our comprehension of evolutionary adaptations and the dynamics of ancient marine habitats.

The significance of this study lies in its illumination of the often-overlooked complexities of predator-prey relationships and the unexpected consequences of feeding strategies in ancient ecosystems. As paleontologists continue to uncover new fossils, the stories of these long-extinct creatures offer invaluable insights into the evolutionary history of marine life.

This research contributes to a growing body of work that seeks to reconstruct the ecological narratives of past eras, shedding light on how organisms adapted to their environments and the challenges they faced, even leading to their downfall.