Apatemyids (Mammalia, Apatotheria) from the middle Chadronian (late Eocene) of Sioux County, Nebraska, US
Bibliographic record
Abstract
The Apatemyidae are a unique radiation of insectivorous mammals known from the Paleogene of North America, Europe, and India. Apatemyids are rare components of the faunas where they are found, and small sample sizes create difficulties in interpreting variation and establishing meaningful taxonomy. Despite disagreement regarding the number of genera and species, there is agreement that two apatemyid genera exist sequentially during the Eocene in North America. The genus Apatemys appears during the Wasatchian and persists through the Duchesnean, followed by Sinclairella, which persists from the Duchesnean through the Arikareean. Here, we describe apatemyid specimens collected from three sites in Sioux County, Nebraska, during field seasons from 2011-2016. All three localities include specimens of Sinclairella dakotensis, nearly doubling the number of known specimens of Sinclairella from Nebraska. In addition, one of these localities, the Whitehead Creek locality, includes two upper molars of a second apatemyid taxon that we assign to the genus Apatemys. Reevaluation of the apatemyid sample from the temporally and geographically proximate Raben Ranch locality suggests that one m1, previously assigned to Sinclairella, belongs to the same species of Apatemys represented at Whitehead Creek. When taken in conjunction with a single M2 from Chadronian-age deposits of the Cypress Hills Formation, Saskatchewan, these new specimens indicate that at least two species of Apatemys persist into the late Eocene of the Great Plains Faunal Province. Moreover, they add to a growing list of taxa that persist as relicts in the Chadronian of the Great Plains after extinction elsewhere.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 teacher head, 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".