A middle Cenomanian euselachian assemblage from the Dunvegan Formation of northwestern Alberta
Bibliographic record
Abstract
A euselachian assemblage was recovered from the middle Cenomanian Dunvegan Formation situated in northwestern Alberta. This assemblage is the most northern described within the Western Interior Seaway and provides an important insight into the euselachian faunal diversity of this little-known region of the seaway. Despite its high paleolatitude, the assemblage contains a number of elasmobranch taxa, including Hybodus , Squalicorax , Archaeolamna , Cretodus , Dallasiella , and Cretoxyrhina . The Dunvegan assemblage also contains the first known reports from Canada of the odontaspid shark Johnlongia parvidens , the cretoxyrhinid shark Protolamna carteri , and the ray Pseudohypolophus mcnultyi . This assemblage extends the northern geographical range of all taxa. Preliminary comparisons with other middle Cenomanian Western Interior Seaway assemblages show that the core composition of the Dunvegan assemblage is remarkably similar to that of other time-equivalent assemblages; however, conspicuously absent are species that are exceedingly common in other localities situated farther south. We suggest that absence of these taxa from the Dunvegan localities may be caused by a temperature intolerance associated with latitude and sea-water circulation patterns, or by an inability to inhabit environments that exhibit salinity variation.
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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 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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 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".