Paleontologists learning a fossil unearthed in southern Manitoba, Canada, have recognized what they imagine are two chew marks on the inner skeleton of the traditional big cephalopod Enchoteuthis, providing uncommon proof of predator-prey interactions within the Cretaceous seas that after lined the center of North America.
Reconstruction of a mosasaur and huge fish preying on an injured Enchoteuthis, representing potential candidates for the chew marks on the octopod. Picture credit score: Kaitlin Lindblad.
“Within the Mesozoic, cephalopods have been probably the most considerable and numerous teams within the marine realm,” College of Manitoba paleontologist Melina Jobbins and colleagues wrote of their paper.
“Cephalopods, together with coleoids and ammonites, served as an ideal meals supply for predators reminiscent of marine reptiles and fish.”
“These predator-prey dynamics are supported by direct proof, reminiscent of specimens with preserved abdomen contents, in addition to oblique proof together with people with fractures or breakage interpreted as chew marks.”
“Nevertheless, figuring out the particular predator from oblique proof carries some uncertainty.”
Within the new examine, the paleontologists examined the fossilized gladius — the inner, pen-like assist construction — of Enchoteuthis, a squid-like creature that swam within the Cretaceous seas round 81 million years in the past.
The specimen, named Q80.05.14, was initially collected in 1980 from the Pierre Shale of Manitoba, and is housed on the Canadian Fossil Discovery Centre.
“Q80.05.14 is ca. 49 cm (19 inches) lengthy and includes a gladius with an almost full rachis and partial patella, with the anterior and posterior edges lacking,” the researchers wrote.
“We offer a tough estimate of complete size of the gladius to be round 60 cm (24 inches), and a complete physique size of lower than 1 m (39 inches).”
Utilizing 3D scanning and silicone casts, the researchers analyzed two sub-triangular pathologies preserved on Enchoteuthis’ gladius.
One, close to the entrance of the construction, is interpreted with extra confidence as a chew mark inflicted shortly earlier than or on the time of the animal’s loss of life, because it exhibits no signal of therapeutic.
The second mark, close to the again, is extra ambiguous: it may symbolize a second chew from the identical assault, harm from a separate encounter, or delamination attributable to the gladius splitting alongside its pure fibrous layers, both in the course of the assault or afterward because the carcass decayed.
As a result of the marks lack embedded enamel or the sort of common tooth spacing that might level to a selected attacker, the scientists couldn’t establish the predator with certainty.
Each a mosasaur reminiscent of Latoplatecarpus, and a predatory fish reminiscent of Cimolichthys, lived alongside Enchoteuthis in the identical historical seaway and stay believable culprits.
Different candidates, together with sharks and the large mosasaur Tylosaurus, have been dominated out primarily based on the form of their bites or enamel.
“Oblique proof of predation reminiscent of chew marks are essential parts to assist us perceive the prey-predator dynamics and contributes to our understanding of the meals webs within the Western Inside Seaway in the course of the Late Cretaceous,” the authors concluded.
Their paper was revealed on August 28, 2026 within the journal Cretaceous Analysis.
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Melina Jobbins et al. Deadly damage within the pen of a squid-like big octobrachian Enchoteuthis from the Cretaceous Pierre Shale of Manitoba, Canada. Cretaceous Analysis, revealed on-line August 28, 2026; doi: 10.1016/j.cretres.2026.106480