Paleontologists studying fossils unearthed in southern Manitoba, Canada, have identified two bite marks on the internal skeleton of a giant ancient cephalopod. Enhoteutis provides rare evidence of predator-prey interactions in the Cretaceous ocean that once covered central North America.
Restoration of mosasaurs and large fish that prey on injured victims Enhoteutis represents a potential candidate for an octopus leg bite mark. Image credit: Caitlin Lindblad.
“During the Mesozoic Era, cephalopods were one of the most abundant and diverse groups in the marine world,” University of Manitoba paleontologist Melina Jobbins and colleagues wrote in the paper.
“Cephalopods, including ammonites and nautiloids, served as an excellent food source for predators such as marine reptiles and fish.”
“These predator-prey relationships are supported by direct evidence, such as specimens with preserved stomach contents, and indirect evidence, such as individuals with fractures or breaks interpreted as bite marks.”
“However, identifying a specific predator from indirect evidence involves some degree of uncertainty.”
In a new study, paleontologists examined a fossilized gladius, an internal pen-like support structure. Enhoteutis, a squid-like creature that swam in the Cretaceous seas about 81 million years ago.
The specimen, named Q80.05.14, was originally collected from Manitoba’s Pierre Cher in 1980 and is housed at the Canadian Fossil Discovery Centre.
“Q80.05.14 is approximately 49 centimeters (19 inches) long and consists of a gladius with an almost complete rachis and partial patella, lacking the leading and trailing edges,” the researchers wrote.
“Gladius is roughly estimated to have a total length of approximately 60 cm (24 inches) and a body length of less than 1 meter (39 inches).”
The researchers used 3D scans and silicone casts to analyze the pathology of the two preserved subtriangles of Enhoteutis Gladius.
One is near the front of the structure and shows no signs of healing, so it is more confidently interpreted as a bite mark made just before or at the time of the animal’s death.
The second mark, near the back, is more vague. This could indicate a second bite from the same attack, damage from another encounter, or detachment caused by tears along the gladius’ natural fibrous layer during the attack or after the carcass has decayed.
Scientists were unable to identify the predator with certainty because the marks lacked embedded teeth or the regular spacing of teeth that would indicate a specific attacker.
Both mosasaurs Latoplatecarpus and other predatory fish like Timorichthys lived alongside Enhoteutis in the same ancient sea, making them likely culprits.
Other candidates, like sharks and giant mosasaurs Tylosaurus, were excluded based on bite and tooth shape.
“Indirect evidence of predation, such as bite marks, is an important element that helps understand prey-predator dynamics and contributes to our understanding of the food web of the Western Interior Seaway during the Late Cretaceous,” the authors concluded.
Their paper was published in the Journal on August 28, 2026, titled Cretaceous Research.
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Melina Jobbins et al. reported a giant octopod bone enclosure resembling a squid that fatally injured Enhoteutis in Pierre Cher, Cretaceous, Manitoba, Canada. Their study was published online on August 28, 2026, in Cretaceous Research, doi: 10.1016/j.cretres.2026.106480.
Source: www.sci.news
