New exceptional specimens of<i>Prognathodon overtoni</i>(Squamata, Mosasauridae) from the upper Campanian of Alberta, Canada, and the systematics and ecology of the genus
Bibliographic record
Abstract
ABSTRACT Currently known from the early Campanian to late Maastrichtian, Prognathodon constitutes a group of mosasaurine mosasaurs that typically possessed massive jaws. Only four articulated skulls are known to date and the information concerning their postcrania remains minimal. Moreover, the early to middle Campanian specimens of the taxon are extremely rare and fragmentary. Two new specimens of Prognathodon overtoni from the early late Campanian (ca. 74.5 Ma) Bearpaw Formation exposed near Welling, southern Alberta, Canada, provide the first fully articulated skeletons of the genus. Detailed morphological assessment of these and pre-existing specimens indicates that many cranial characters are shared between P. overtoni and the generic type P. solvayi from the early Maastrichtian, including (1) short premaxillary-maxillary suture; (2) short triangular frontal with marked anterior constriction; and (3) distinct, blind-ended median opening on medullary floor of basioccipital. These are interpreted as generically diagnostic characters, and the first character in particular distinguishes Prognathodon from Liodon and other long-snouted mosasaurines. The postcranium of P. overtoni is lightly built, and differs very little from that of Clidastes, a basal mosasaurine. Marginal teeth are carinate with fine crenulations, indicating their proposed opportunistic predatory behavior. Additionally, most of the fully erupted teeth exhibit a similar degree of apical wear, which is interpreted as indicating that the taxon regularly handled prey items that involved crunching. To augment these dietary inferences, gut contents from one of the new specimens include fragments of a large and a small fish, a sea turtle, and possibly a cephalopod.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 teacher head, 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".