The social ecology of mosasaurs as evidenced by traumatic paleopathologies
Bibliographic record
Abstract
Herein I examine a long-standing hypothesis about agonistic social interactions in Mosasauridae, an extinct family of Late Cretaceous marine toxicoferan lizards. Previous studies on mosasaur agonism presented idiosyncratic evidence, which limited behavioral interpretations. To test the hypothesis that mosasaur aggression can be quantitatively studied and better understood through the lens of their closest relatives, I first conducted a review assessing paleopathological evidence for intraspecific agonism in the fossil record. I adapted existing, well-constrained anthropological methods of identifying traumatic paleopathology to create a framework applicable to fossil research. Next, I tested the established framework in a case study using data from prior mosasaur pathology studies and new observations to identify trends, finding that agonism-attributed features are widespread across Mosasauridae. In addition, unhealed features contradict morphological, and orientation trends observed in healed features. When cross-referenced with shark-attributed features, most unhealed confamilial mosasaur bites imply scavenging rather than deadly attacks. Damage attributed to mosasaurs is predominantly antemortem (77%), cranial (81%), and horizontally oriented; damage attributed to sharks is predominantly peri/postmortem (97%), broadly spread across skeletons, and vertically oriented. Finally, I conducted a systemic paleopathological survey (244 specimens, 2209 elements) of North American mosasaurid skull material to determine frequency, morphology, ontogeny, and taxonomic patterns of cranial trauma pathologies with comparison to known behaviors of modern relatives. 119 total lesions are documented (65 elements, 2.9%) across 39 specimens (15.9%). Pathologies are most common on the anterior snout and are commonly parallel to the tooth row. Pathology frequency correlates with size class, with larger specimens showing more features. One-third of marked specimens show features at different healing stages, implying recurrent behaviors. Cranial pathologies are taxonomically widespread, suggesting this behavior is plesiomorphic for Mosasauridae. These pathologies may result from male-male intrasexual aggressive behavior, as seen in extant varanids and snakes, and their onset at 40-60% maximum size may indicate sexual maturity. If this is correct, consistent absence of these pathologies in the largest specimens may be indirect support for reverse sexual size dimorphism in some mosasaurs, sensu modern snakes. Overall, this study provides new insights into the lives of these marine lizards and helps differentiate behaviors.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
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".