Credit: Geological Magazine (2023). DOI: 10.1017/S0016756823000456
Phys.org has an interesting post about a fish that died from indigestion. The fish, an actinopterygian named Pachycormus macropterus, lived during the Jurassic Period between 174 and 182 million years ago. Its fossil was found in Germany in the Posidonienschiefer Formation. It swallowed an ammonite, which was much to large for it to digest. Read all the details in the paper "Death by ammonite: fatal ingestion of an ammonoid shell by an Early Jurassic bony fish", which appeared in Geological Magazine.
The researchers found its belly full of a variety of prey. They found evidence of soft-bodied mollusks that looked somewhat like modern cuttlefish or squid and other smaller fish. They also found a large ammonite conch approximately 10 centimeters across, which did not show signs of digestion, a sign that the fish had died soon after swallowing the shelled creature.
The ammonite, the researchers note, was much too big for the fish to digest. They suggest that it was likely misidentified by the fish or it somehow became stuck in its mouth for an unknown reason. At that point, the fish would have been unable to eject it from its mouth, leaving no choice but to swallow it. Once it did that, the ammonite's shell blocked passage to the intestine, resulting in either congestion or internal bleeding. Either would have killed the fish within hours.
