2025/06/10 by Sreepat Jain, Mariusz A. Salamon, Christian Klug +3 · 1 citation
Earth and Planetary Sciences · #Paleontology and Evolutionary Biology #Paleontology and Stratigraphy of Fossils #Evolution and Paleontology Studies
paper · doi:10.18261/let.58.3.5
The records of sub-lethally or lethally injured nautilids are rare, as are their Bathonian (Middle Jurassic) occurrences. Here, we report a large nautilid (88 mm shell diameter) from the Polish Jura (southern Poland), which was ventrally bitten at its phragmocone. It is a Cenoceras sp. from the middle Bathonian (Bremeri Zone) of the Gnaszyn brick-pit associated with the ammonite Prohecticoceras. Although coeval strata have yielded records of predatory shark teeth belonging to Palaeobrachaelurus, Protospinax, Sphenodus, and an orectolobiform, the bite traces on the nautilid are morphologically different and are at least 13 times larger, thus ruling out sharks as predators. Other plausible predators include marine reptiles such as pliosaurid plesiosaurs, thalattosuchian crocodylomorphs or ichthyosaurs, other cephalopods such as large squids, ammonites or even nautilids (including cannibalism). Based on the morphology and dimensions of the bite marks, the most likely candidate appears to be a pliosaurid whose remains have been well-recorded from the Middle and Upper Jurassic rocks of Poland. Regarding the predation attempt, it appears to have been lethal but possibly was a failed attack from the right side of the organism, as evidenced by the bite marks on its ventral surface. It is conceivable that the plesiosaur was unable to grasp the thick and presumably slippery nautiloid firmly after the first bite as reflected by the presence of only two 20 mm-wide bite marks, and then dropped the nautilid. Alternatively, it managed to rip the soft parts out of the conch and dropped the latter without further crushing it.