An Extinct Genus of Fish from the Jurassic Period Had a Fatal Attraction to Belemnites
An extinct genus of ray-finned fish that roamed the oceans during the Jurassic period seems to have had a fatal attraction to belemnites, as revealed by a recent analysis of fossilized Tharsis fish.
Paleontologists Martin Ebert and Martina Kölbl-Ebert from Ludwig Maximilian University of Munich in Germany discovered multiple instances of Tharsis fish from the 152 million-year-old Solnhofen Plattenkalk formation in Germany with belemnites lodged in their mouths and gills. These carnivorous marine creatures seemed to have met their demise while trying to swallow large cephalopods almost as long as themselves.

The researchers noted that the belemnites’ internal shells were firmly lodged in the fish’s mouth opening, leading to their untimely demise.
Micro-Carnivores with a Deadly Habit
Tharsis fish were micro-carnivores that fed on small prey like larvae and zooplankton by using suction to ingest their food. Fossils of these fish are abundant in the Solnhofen Plattenkalk formation.
On the other hand, belemnites, squid-like creatures with a long body and numerous arms, were inhabitants of the open ocean and left fewer fossils behind. The belemnite fossils found in the Plattenkalk basins often showed signs of colonization by other marine organisms, indicating that the belemnites were likely dead and drifting in the water column.

The researchers speculated that the Tharsis fish might have mistakenly sucked the belemnites into their mouths while feeding on decaying organic matter or algae attached to these floating objects. Once trapped, the fish struggled to expel the belemnites, ultimately leading to suffocation and death.
This peculiar behavior sheds light on the interactions between ancient marine creatures and highlights the dangers of indiscriminate feeding habits in a hostile underwater environment.
The study detailing this fascinating discovery has been published in Scientific Reports.