A chasmosaurine ceratopsid premaxilla from the basal sandstone of the Hell Creek Formation, Montana
Bibliographic record
Abstract
A well-preserved large chasmosaurine ceratopsid premaxilla (MOR 1122 7-22-00-1) collected from the basal sandstone of the Cretaceous Hell Creek Formation (HCF) represents one of the stratigraphically lowest ceratopsid occurrences in the formation. The specimen was discovered in 2000, during the excavation of a large Torosaurus latus skull (MOR 1122) which was later hypothesized to represent an advanced growth stage of the more commonly recovered HCF ceratopsid Triceratops. MOR 1122 7-22-00-1 compares favorably with the incomplete premaxillae of the MOR 1122 skull and reveals details of premaxilla morphology from this stratigraphic zone. It preserves large, closely spaced ventromedial foramina, a narrow triangular process, and a thin septal flange at the base of the narial strut. The nasal process is narrow, caudally inclined and has a forked dorsal surface which appears to represent an intermediate between the morphology expressed in the slightly stratigraphically lower ceratopsid Eotriceratops xerinsularis from the Horseshoe Canyon Formation of Alberta and specimens recovered higher in the HCF. MOR 1122 7-22-00-1 expresses a deep recess extending medial to the strut of the triangular process, a feature shared with other HCF ceratopsid specimens but not Eotriceratops or other earlier occurring triceratopsin taxa. The morphology of MOR 1122 7-22-00-1 is consistent with noted stratigraphic trends in HCF ceratopsids and highlights the increased complexity of the narial region in uppermost Cretaceous triceratopsins.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 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) | 0.004 | 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".