An Eocene brontothere and tillodonts (Mammalia) from British Columbia, and their paleoenvironments
Bibliographic record
Abstract
We describe Eocene fossils of the tillodont Trogosus from the Allenby Formation in Princeton, British Columbia (B.C.), as well as teeth of Brontotheriina from the lower Australian Creek Formation near Quesnel, B.C. These fossils represent the only occurrence of Tillodontia and Brontotheriidae in B.C. Further, the presence of the largest species of Trogosus — T. latidens — as well as a smaller species identified only as Trogosus sp. supports a late early – early middle Eocene (Bridgerian) age for the Vermilion Bluffs Shale of the Allenby Formation. Based on their morphology and large size, the teeth referred here to Brontotheriina represent one of the larger, more derived brontothere genera, and suggest a Uintan–Chadronian (middle–late Eocene) age range for the lower Australian Creek Formation that is consistent with radiometric ages of underlying volcanic rocks. Paleobotanical data from sediments correlative to those that produced these Eocene mammal fossils suggest they inhabited forested landscapes interspersed with swamps and open water environments, under mild and wet temperate climates (mean annual temperature (MAT) ∼10–16 °C; cold month mean temperature (CMMT) −4–4 °C; mean annual precipitation (MAP) >100 cm/year). These mixed conifer–broadleaf forests included tree genera typical of modern eastern North American forests (e.g., Tsuga, Acer, Fagus, and Sassafras), together with genera today restricted to east Asia (e.g., Metasequoia, Cercidiphyllum, Dipteronia, and Pterocarya). The paleobotanical evidence is consistent with the hypothesized habitats of both tillodonts and brontotheres.
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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 | 0.000 | 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 | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 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".