![\"Reconstruction](\"https:\/\/cdn.sci.news\/images\/enlarge14\/image_15034e-Enchoteuthis.jpg\")
<\/a><\/p>\nReconstruction of a mosasaur and large fish preying on an injured Enchoteuthis, representing potential candidates for the bite marks on the octopod. Image credit: Kaitlin Lindblad.<\/p>\n
\u201cIn the Mesozoic, cephalopods were one of the most abundant and diverse groups in the marine realm,\u201d University of Manitoba paleontologist Melina Jobbins and colleagues wrote in their paper.<\/p>\n
\u201cCephalopods, including coleoids and ammonites, served as a great food source for predators such as marine reptiles and fish.\u201d<\/p>\n
\u201cThese predator-prey dynamics are supported by direct evidence, such as specimens with preserved stomach contents, as well as indirect evidence including individuals with fractures or breakage interpreted as bite marks.\u201d<\/p>\n
\u201cHowever, identifying the specific predator from indirect evidence carries some uncertainty.\u201d<\/p>\n
In the new study, the paleontologists examined the fossilized gladius \u2014 the internal, pen-like support structure \u2014 of Enchoteuthis<\/a>, a squid-like creature that swam in the Cretaceous seas around 81 million years ago.<\/p>\n The specimen, named Q80.05.14, was originally collected in 1980 from the Pierre Shale of Manitoba, and is housed at the Canadian Fossil Discovery Centre.<\/p>\n \u201cQ80.05.14 is ca. 49 cm (19 inches) long and comprises a gladius with a nearly complete rachis and partial patella, with the anterior and posterior edges missing,\u201d the researchers wrote.<\/p>\n \u201cWe provide a rough estimate of total length of the gladius to be around 60 cm (24 inches), and a total body length of less than 1 m (39 inches).\u201d<\/p>\n Using 3D scanning and silicone casts, the researchers analyzed two sub-triangular pathologies preserved on Enchoteuthis\u2019 gladius.<\/p>\n One, near the front of the structure, is interpreted with more confidence as a bite mark inflicted shortly before or at the time of the animal\u2019s death, since it shows no sign of healing.<\/p>\n The second mark, near the back, is more ambiguous: it could represent a second bite from the same attack, damage from a separate encounter, or delamination caused by the gladius splitting along its natural fibrous layers, either during the attack or afterward as the carcass decayed.<\/p>\n Because the marks lack embedded teeth or the kind of regular tooth spacing that would point to a specific attacker, the scientists could not identify the predator with certainty.<\/p>\n Both a mosasaur such as Latoplatecarpus<\/a>, and a predatory fish such as Cimolichthys<\/a>, lived alongside Enchoteuthis in the same ancient seaway and remain plausible culprits.<\/p>\n Other candidates, including sharks and the gigantic mosasaur Tylosaurus<\/a>, were ruled out based on the shape of their bites or teeth.<\/p>\n \u201cIndirect evidence of predation such as bite marks are crucial elements to help us understand the prey-predator dynamics and contributes to our understanding of the food webs in the Western Interior Seaway during the Late Cretaceous,\u201d the authors concluded.<\/p>\n