A new tribotherian (Mammalia, Boreosphenida) from the late Santonian to early Campanian upper Milk River Formation, Alberta
Bibliographic record
Abstract
A new tribotherian mammal, Tirotherium aptum gen. et sp. nov., is described from the late Santonian to early Campanian upper Milk River Formation of Verdigris Coulee, southern Alberta, Canada. The new mammal is known only from isolated teeth, five upper and three lower molars. The upper molars represent two or possibly three pre-ultimate loci and are marked by reduction and loss of the stylar shelf anteriorly, loss of the stylocone, a paracone that is larger than the metacone, weakly developed conules, a low, small protocone, and specialized postvallum single-rank shear. The lower molars probably represent two pre-ultimate loci and are characterized by an anteriorly positioned paraconid, trenchant paracristid, small, posterolingual metaconid, a distal metacristid, broadly open trigonid angle, and a short, basined talonid in which the hypoconulid is closer to the entoconid than to the hypoconid. The molars of Tirotherium most closely resemble those of Picopsis Fox, 1980, a tribotherian that also occurs in the upper Milk River Formation, but the molars of Tirotherium are significantly larger than those of Picopsis. Nonetheless, Tirotherium aptum is best classified in the Picopsidae, a boreosphenidan family of tiny mammalian faunivores of uncertain relationships to other tribotherians, and displaying a unique mosaic of primitive and derived characters.
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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 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 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".