The first substantive evidence of <i>Utatsusaurus</i> (Ichthyopterygia) from the Sulphur Mountain Formation (Lower–Middle Triassic) of British Columbia, Canada: a skull roof description in comparison with other early taxa
Bibliographic record
Abstract
We describe the skull roof anatomy of PRPRC 2007.08.81, a new specimen of late Olenekian (Spathian) ichthyopterygian from the Vega-Phroso Siltstone Member of the Sulphur Mountain Formation of British Columbia, Canada. Based on the presence of a well-developed anterolateral prefrontal process, parietal that is deeply excavated along its posteromedial margin, and skull roof sutural patterns, PRPRC 2007.08.81 closely resembles other Olenekian forms such as Utatsusaurus, Grippia, Chaohusaurus, and Gulosaurus (a new taxon recently described from British Columbia, Canada). However, due to their shared apomorphic supratemporal terrace morphology, PRPRC 2007.08.81 is identified as Utatsusaurus sp. With the only other known conclusive Utatsusaurus material retrieved from the Osawa Formation (Lower Triassic) of Japan, the broad palaeogeographic distribution of this taxon suggests a radiation event for Ichthyopterygia occurring prior to the latter part of the Olenekian. However, despite this inference, the palaeogeographic origin of Ichthyopterygia continues to be unclear; only the acquisition and interpretation of additional chronologically early ichthyopterygian material will resolve the early evolutionary history of this group.
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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 | 0.003 |
| Science and technology studies | 0.004 | 0.002 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 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".