The Solnhofen limestone preserves many Aspidorhynchus fossils often found as decapitated heads still attached to gut contents. A study of 343 specimens found about 16% in this partial state and used stomach remains to identify small teleosts (Orthogonicleithridae) as primary prey. The authors propose that larger predators bit tails and violently tore prey apart, leaving heads and guts behind. Known potential attackers include ichthyosaurs, marine crocodiles, and pliosaurs.
Decapitated Jurassic Fish Reveal Violent Feeding Behavior in Ancient Seas
The Solnhofen limestone preserves many Aspidorhynchus fossils often found as decapitated heads still attached to gut contents. A study of 343 specimens found about 16% in this partial state and used stomach remains to identify small teleosts (Orthogonicleithridae) as primary prey. The authors propose that larger predators bit tails and violently tore prey apart, leaving heads and guts behind. Known potential attackers include ichthyosaurs, marine crocodiles, and pliosaurs.
06:00 AM, 11/20/2025Science
In the limestone beds of present-day Germany, researchers have uncovered a striking pattern of preservation: decapitated heads of predatory fish preserved together with their gastrointestinal tracts. The famous Solnhofen deposits, a Late Jurassic lagerstätte (about 161.5–143.1 million years ago), have yielded numerous specimens of the marlin-like predator Aspidorhynchus in this unusual partial state.
Partial fossils that tell a story
These remains are not intact skeletons but largely severed skulls still connected to gut contents. A recent study in the journal Fossil Record examined 343 Aspidorhynchus specimens and found that roughly 16% consisted only of the head and attached gut. Beyond the extraordinary mode of preservation, these fossils capture both the predators' last meals and the events surrounding their deaths.
Diet and hunting style
Aspidorhynchus resembled modern swordfish or marlins, routinely exceeding three feet in length (about 0.9 m) and sporting an elongated, spear-like upper jaw. From stomach contents, the researchers concluded that these fish fed mainly on small teleosts, especially members of the family Orthogonicleithridae. Many stomachs contain whole juvenile teleosts, indicating that Aspidorhynchus often swallowed small prey whole; occasionally specimens show much larger prey items, such as a ~22-inch (≈56 cm) Aspidorhynchus preserved with a 6.3-inch (≈16 cm) fish in its gut. In another example, a small fish lodged in the mouth appears to have caused the predator to drown.
"Judging from their body shape and fin morphology, it is highly likely that Aspidorhynchus was a pursuit predator. From its stomach contents, we know that it fed mainly on small teleosts (Orthogonicleithridae)," said Martin Ebert.
Why so many decapitated specimens?
The high number of head-and-gut-only fossils prompted the authors to propose an ecological explanation: larger predators attacked Aspidorhynchus, biting the tail and then shaking violently to tear the prey apart. This tearing action would detach the head while leaving the body—the more nutritious portion—to be consumed. Such attacks would naturally leave behind the severed heads attached to gut contents that later became fossilized.
The researchers point to several plausible attackers in the Solnhofen archipelago, including ichthyosaurs, marine crocodiles, and pliosaurs, animals large enough (roughly 2–4 m / 6.5–13 ft in known examples) to bite and tear mid-sized fish.
Significance
These partial fossils provide a rare snapshot of predator-prey interactions in the Late Jurassic Tethys Ocean, linking stomach contents with evidence of violent consumption by larger hunters. Together, they shed light on the structure of ancient marine food webs and on the behaviors that left durable marks in the fossil record.