New <i>Saurorhynchus</i> (Actinopterygii: Saurichthyidae) material from the Early Jurassic of Alberta, Canada
Bibliographic record
Abstract
Saurichthyidae are a family of elongate, piscivorous actinopterygian fishes with a stratigraphic range extending from the late Permian to the Middle Jurassic. There are four recognized Early Jurassic species, all from Europe and all referred to the genus Saurorhynchus. Only a single non-European Jurassic occurrence has been reported, a partial Saurorhynchus skull from the Fernie Formation of western Alberta, Canada. Here, we evaluate the Saurorhynchus material from Canada, including a new skull from Ya Ha Tinda, Alberta, and a fragmentary mandible from Canyon Creek, Alberta. All diagnostic Canadian Saurorhynchus specimens are consistent with the European species Saurorhynchus acutus, on the basis of external narial morphology and reduced dermal ornamentation. Saurorhynchus acutus was present in the Toarcian of western North America from the tenuicostatum Zone to the late serpentinum – early bifrons Zone, similar to the stratigraphic range documented in Europe. The absence of divergence between eastern Panthalassan and western Tethyan saurichthyids is surprising, given that divergence has been well-documented in coeval invertebrates. Saurorhynchus may have had slower rates of morphological evolution than contemporaneous marine invertebrates; alternatively greater mobility, broader environmental tolerance, or both in these fish may have allowed ongoing gene flow between the two oceanic basins in the early Toarcian.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.004 | 0.004 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.007 | 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".