Conodont bio-events, cladistics and response to glacio-eustasy, Ordovician-Silurian boundary through Llandovery, Anticosti Basin, Québec
Bibliographic record
Abstract
Abstract Conodont diversity was severely reduced during the terminal Ordovician mass extinction. Few species, mainly coniform taxa, survived across the Ordovician-Silurian boundary. The nature and timing of the post-extinction recovery and diversification have previously been difficult to assess, due to limited knowledge and preservation of the earliest Silurian faunas. Recent documentation of early Llandovery conodont faunas from a complete stratigraphic succession on Anticosti Island, Québec, along with the data re-examined from earlier detailed studies, provides the basis for a new analysis. Five evolutionary cycles are recognized through the Llandovery, together with a distinct set of bio-events that are interpreted as immigration, emigration, origination, and extinction events through consideration of global occurrence data for Llandovery conodonts. These events are supported by the detailed sampling and stratigraphic range data, as well as the first cladistic analysis of the four key genera: Oulodus, Ozarkodina, Pterospathodus , and Rexroadus . The Anticosti Basin may have been an important centre of evolutionary radiation, given that several genera and species have first appearances in this region and that initial evolutionary lineages can be established for many taxa. Many faunal variations appear to be correlated to eustatic events as well as the changing ocean-climate state through this boundary interval.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| 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".