An ichthyosaur rostrum from the uppermost Albian of Saskatchewan (Canada) represents the youngest diagnosable Canadian ichthyosaur prior to their demise
Bibliographic record
Abstract
A partial ichthyosaur rostrum from late Albian-aged Ashville Formation deposits in southern Saskatchewan is described here. Previously referred to ' Platypterygius' americanus (Nace, 1939), the well-preserved rostrum includes the snout tip and several articulated teeth. Based on the unique anteroventral curvature of the snout and proportions of the premaxilla, dentary, and teeth, the specimen is reaffirmed as ' P.' americanus with diagnostic traits in spite of the lower Cenomanian age for the type and previously referred material for this taxon. The Saskatchewan specimen extends 'P.' americanus to the late Albian, and the species would have inhabited the Western Interior Seaway along with other marine predators with varied diets. The teeth of the Saskatchewan specimen are generalist in morphology due to their large size and robust crowns. Further research is required to shed light on ichthyosaur snout anatomy and evolution immediately prior to their extinction by the late Cenomanian. The early Cenomanian age of the Wyoming ' P.' americanus and late Albian age of the Saskatchewan specimen may ultimately reveal a novel taxon in the Ashville Formation as more complete material is found.
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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 | 0.002 | 0.003 |
| Science and technology studies | 0.004 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.002 |
| 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".