Unique find: fossilized fish that died after swallowing an ammonite

In Germany, paleontologists from the Stuttgart State Museum of Natural Sciences at the University of Hohenheim have discovered an amazing fossil – a Jurassic fish that apparently died after swallowing an ammonite that was too large. The find, which dates from 174-182 million years ago, opens new horizons in the study of the food habits of ancient sea creatures.

The fossil, named Pachycormus macropterus, was found in the Posidonienschiefer Formation, which is one of the richest sources of Jurassic fossils. The fish belonged to the type of actinopterygians, a bony ray-finned fish of which the lionfish is a modern example.

The most surprising part, however, lies in the stomach contents of this fish. The researchers found traces of soft-bodied mollusks similar to modern cuttlefish and squid, as well as small fish. But most impressive was the presence of a large ammonite measuring about 10 centimeters that had not been digested. This suggests that the fish died shortly after swallowing the shell creature.

According to the researchers, the ammonite was too large for the fish to digest. The fish probably misjudged the size of the ammonite or, for some unknown reason, it got stuck in its mouth. In this case, the fish had no choice but to swallow its prey. However, the shell of the ammonite blocked the passage to the intestine, resulting in either blood stasis or internal bleeding. Either way, the fish died just a few hours after ingestion.

After death, the fish sank to the bottom of the sea where it was buried in silt. Over time, it became entombed with the contents of its stomach, allowing this unique fossil to be preserved. Researchers note that the preservation of the ammonite is simply “superb”, which makes this find even more valuable.

This find is the first documented case of a lethal last meal in an extinct pachycormid fish. Not only does it provide us with a unique glimpse into the life and death of ancient sea creatures, but it also indicates that ammonites may have been a more common food for bony fishes in the Jurassic than we previously thought.

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