Pragian conodont zonal classification in Nevada, western North America
Bibliographic record
Abstract
A tripartite global zonal scale for the Pragian Stage (Devonian) was recommended by the Subcomission on Devonian Stratigraphy in 1989. Since that time, additions to the data on the two primary lineages used for the subdivision of the Pragian, Eognathodus and early Polygnathus, have shown: 1) that the Lochkovian-Pragian boundary criterion is useable as defi ned and is applicable on a global scale, but that the boundary-stratotype section in the Barrandian region of the Czech Republic has serious limitations as a reference section; 2) the criteria for the internal subdivision of the Pragian are not globally applicable; and 3) that the taxon that we have used in Nevada to mark the base of the Emsian is Polygnathus lenzi, whose range may be different from that of Australian P. dehiscens, the supposed criterion for the base of the Emsian. This paper reviews the Pragian of Nevada and compares it with Alaska, Canada, eastern Australia, and central Europe and suggests a regional scale for use in the western North American Cordillera. The subdivisions proposed here (irregularis-profunda Zone; profunda–brevicauda Zone; brevicauda-mariannae Zone; mariannae-lenzi Zone) are not the same of the SDS and cannot be applied on a global scale. The first two are based on evolutionary appearances; the last two on the lowest occurrences of distinctive and widespread taxa in North America. One new genus, Masaraella and four new species, Masaraella epsilon, Masaraella riosi, Gondwania profunda, and Pedavis longicauda, are described.
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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 | 0.003 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".