Cranial morphology and relationships of a new grippidian (Ichthyopterygia) from the Vega-Phroso Siltstone Member (Lower Triassic) of British Columbia, Canada
Bibliographic record
Abstract
ABSTRACT In 1989, TMP 89.127.3, a basal ichthyopterygian, was collected as a counterpart slab from the Vega-Phroso Siltstone Member (Lower Triassic) of the Sulphur Mountain Formation in east-central British Columbia, Canada. Previous investigations of its postcranial skeleton resulted in ambiguous taxonomic affinities, with it being identified as either Grippia cf. longirostris or Parvinatator wapitiensis. More recently, the part slab of TMP 89.127.3 was collected and prepared, revealing important new cranial data that permits its systematic relationships to be more thoroughly assessed and previously proposed taxonomic affinities to be tested. By integrating both cranial and postcranial data, phylogenetic analysis recovers TMP 89.127.3 and Grippia as members of Grippidia, nested within Eoichthyosauria. TMP 89.127.3 can be distinguished from Grippia by possessing the following autapomorphies: metacarpal I with a notched peripheral shaft; cylindrical anterior teeth with a crown shape index >5.0; and a postfrontal-frontal contact at the rostral limit of the anterior margin of the supratemporal terrace. A new taxon, Gulosaurus helmi, is erected to accommodate this suite of features. The placement of Gulosaurus helmi within Grippidia reaffirms the Early Triassic distribution of this clade to include western and northern Laurasia, which is represented by outcrop in present-day Canada and Norway (Spitzbergen), respectively. SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline/UJVP
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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 | 0.000 | 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) | 0.004 | 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".