Paleontologists from the University of Toronto Mississauga have uncovered numerous tooth impressions in the fossilized bones of three juvenile Diadectes, one of the earliest large herbivorous vertebrates to traverse land. This groundbreaking finding represents the earliest direct evidence of predator-prey interactions between terrestrial carnivores and herbivores.
Skeletal reconstruction of Diadectes sideropelicus. Side view illustrating left and right tooth and hole marks. Image credit: Young et al., doi: 10.1038/s41598-026-38183-6.
Paleontologists have long been aware of the existence of apex predators in the Permian landscape; however, clear physical evidence confirming their dependence on the early large herbivores has remained elusive.
In contrast to the Mesozoic Era, renowned for its dinosaur bite marks, the earlier fossil record reveals scant direct evidence of such predator-prey encounters.
“Our findings indicate that the predator-prey hierarchy emerged earlier than previously understood,” stated lead author Professor Robert Rice, a paleontologist at the University of Toronto Mississauga.
“While these interactions are well-documented in the ‘age of reptiles,’ there has been limited information regarding them in the Paleozoic era, when terrestrial vertebrates first evolved into large apex predators and herbivores.”
In this study, Professor Rice and colleagues analyzed the disarticulated skeletons of three juvenile Diadectes, dating back to the early Permian period.
The fossils were unearthed in the Mud Hill area of the Vale Formation located in Texas, USA.
The paleontologists documented five distinct types of bone damage: shallow notches, deeper holes, grooves along the shafts, conical punctures, and small holes.
Notably, many marks were concentrated around cartilage-rich joints, indicating predators had stripped away muscle and pried open connective tissues.
Some grooves ran parallel to the long axis of the bone, consistent with the motion of tearing flesh.
“The holes, pits, cuts, and wrinkles present on these three juvenile herbivores’ skeletons point to the presence of large predators in this area, such as Varanopus and Dimetrodon,” said lead study author Jordan M. Young, a researcher at the University of Toronto Mississauga.
“Scavengers and small arthropods also took part in this ‘Paleozoic feast.’”
Evidence of arthropod perforation was found where the cartilage of the bone ends would have been.
The study was published in the Journal on February 26, 2026, in a Scientific Report.
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JM Young et al. 2026. The earliest direct evidence of trophic interactions between terrestrial apex predators and large herbivores. Scientific Reports 16, 6977; doi: 10.1038/s41598-026-38183-6
Source: www.sci.news
