First Fossils of Hyenas (<i>Chasmaporthetes</i>, Hyaenidae, Carnivora) from North of the Arctic Circle
Bibliographic record
Abstract
The northern region of Beringia is ecologically and biogeographically significant as a corridor for biotic dispersals between the Old and New Worlds. Large mammalian predators from Beringia are exceedingly rare in the fossil record, even though carnivore diversity in the past was much higher than it is in this region at present. Here we report the first fossils of cursorial hyenas, Chasmaporthetes, in Beringia and north of the Arctic Circle. Two isolated teeth recovered in the Old Crow Basin, Yukon Territory, Canada, were identified amongst over 50,000 known fossil mammal specimens recovered from over a century of collecting in the Old Crow Basin. These rare records fill an important intermediary locale in the more than 10,000 km geographic distance between previously known New and Old World records of this lineage. The Pleistocene age of these fossils, together with its Arctic Circle occurrence, necessitate a rethinking of the role of large-bodied hunter-scavengers in Ice Age megafaunas in North America, and the implications of lacking an important energy flow modifier in present day North American food webs.
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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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".