The<scp>L</scp>eporid<scp>D</scp>atum: a late<scp>M</scp>iocene biotic marker
Bibliographic record
Abstract
Abstract AlthoughLagomorpha (rabbits, hares and pikas) have a long evolutionary history inEurasia andAfrica, including primitive genera ofEurasia historically considered assignable at the family level toLeporidae, the predecessors of modern rabbits were absent throughout this vast region for most of theMiocene until late in that epoch. During the early and middleMiocene, crown groupLeporidae differentiated inNorthAmerica, then dispersed to northernAsia in the lateMiocene around 8 Ma(million years before present) and afterward. They then spread widely and apparently rapidly throughoutEurasia, reachingSouthAsia by 7.4 Maand penetratingAfrica about 7 Ma. The apparently abrupt introduction ofLeporidae is a striking lateMiocene event that we call theLeporidDatum. Perceived in terms of biochrons, theLeporidDatum includes localities inEurope and westernAsia of lateMN11 (MammifèresNéogènes system) age and younger, and precedes by less than one million years theBahean‐Baodean land mammal age boundary inChina. The lateMiocene spread ofLeporidae throughoutEurasia was a successful invasion in terms of the numerous occurrences and abundant fossils preserved. Where dating is sufficiently robust, theLeporidDatum is lateMiocene, nowhere certainly more than ∼8 Ma. In contrast to this sudden and widespread invasion, rare older finds suggest two possible refinements to this scenario: stem lagomorphs close to modernLeporidae may have lingered into the middleMiocene ofEurasia, or an independent, unsuccessful leporid invasion fromNorthAmerica may have preceded the 8 Madatum. TheLeporidDatum marks an important palaeoecological event for theOldWorld and complements the significance of molecular dates for origins of modern genera.
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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 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.002 |
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".