An articulated skeleton of<i>Varanops</i>with bite marks: the oldest known evidence of scavenging among terrestrial vertebrates
Bibliographic record
Abstract
The Latest Carboniferous to the Early Permian (305-270 mya) is one of the most important periods in vertebrate evolution because it marks the appearance of the first complex terrestrial vertebrate communities and the initial, rapid evolutionary radiation of amniotes (Sues and Reisz, 1998). In contrast to younger Mesozoic and Cenozoic communities, however, little is known about the trophic structure of these early vertebrate assemblages, or the feeding habits of their constituents. There have been numerous reports and analyses of Mesozoic tooth marks in both terrestrial and marine environments (Erickson, 1996; Fiorillo, 1991), and possible bite marks have been suggested in early aquatic tetrapods (Shubin et al., 2004). Previous reports of evidence of feeding behavior among Paleozoic terrestrial vertebrates, however, have been restricted mainly to the preservation of small tetrapods as supposed stomach contents of large predators such as Dimetrodon (Romer and Price, 1940; Reisz, 1986), or the strange preservation of a skull of the early eureptile Captorhinus with another, somewhat smaller skull of the same species stuck in its mouth (Eaton, 1964). We report on the discovery of a new, large articulated skeleton of the early Permian synapsids predator Varanops displaying numerous bite marks, indicating that the carcass was scavenged by a large tetrapod. The identity of this scavenger as a temnospondyl, probably a dissorophoid, is confirmed by the anatomy of the bites and the remarkable preservation of a broken single tooth crown lodged in the forelimb of the Varanops skeleton.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".