Bibliographic record
Abstract
The middle Cretaceous is usually associated with numerous climatic and oceanic perturbations, and a minor to intermediate extinction event at the Cenomanian-Turonian (CTB) boundary. Amongst marine vertebrate palaeontologists, the CTB is mostly known as the extinction of the last ichthyosaurs (Reptilia), after a long period of decline (e.g. Bardet, 1992; Bardet, 1994; Sander, 2000; Lingham-Soliar, 2003). However, new data from France, Canada and Russia indicates that the diversity of late Early Cretaceous ichthyosaurs was far higher than previously thought, both in terms of taxonomical and ecological diversity, but the Cenomanian ichthyosaur diversity remains extremely low. This suggests that the ichthyosaur extinction is far more severe than initially thought and took place during the whole duration of the Cenomanian, in a diachronic fashion. Additionally, a compilation of the current data on the diversity of other marine vertebrates groups shows that the Cenomanian is a peculiar stage within the Cretaceous, with the radiation burst of marine squamates, such as dolichosaurs and mosasauroids (Bardet et al., 2007; Bardet et al., 2008), as well as chondrichtyans, polycotylid plesiosaurs and teleost fishes (e.g. Cumbaa et al., 2010; Schultze et al., 2010). This profound reorganisation of the marine ecosystems (coeval with the onset of the “Chalk sea”) was probably driven by external, physical factors given the diversity of biotic responses. The numerous potential causes for that major reorganisation renders the identification of its precise mechanisms difficult.
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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 | 0.001 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.008 | 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".