Testing the Competition Hypothesis: How Niche Overlap Between Carnivoramorphans and Creodonts Changed From the Start to the End of the Eocene
Bibliographic record
Abstract
Carnivoramorphans and creodonts are two groups of ancestrally carnivorous mammals that both emerged in the Paleocene (66-56 Ma) of North America.During the Eocene (56-33.9Ma), carnivoramorphans radiated into some of the taxonomic groups we still see today, while creodont diversity declined until the group went extinct in North America during the Oligocene (33.9-23Ma) and worldwide during the Miocene (23-5.3Ma).In this thesis, I test the hypothesis that competition with carnivoramorphans may have led to the extinction of the creodonts in North America by examining changes in niche overlap between the two groups from the start to the end of the Eocene.My results do not support the competition hypothesis, but instead suggest that creodonts were hyperspecialized and un-equipped for the dramatically different environments of the late Eocene and early Oligocene.
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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 | 0.001 | 0.003 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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 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".