Additions to the Chadronian Mammalian fauna, Florissant Formation, Florissant Fossil Beds National Monument, Colorado
Bibliographic record
Abstract
ABTRACT New discoveries in the latest Eocene-aged Florissant Formation in Florissant Fossil Beds National Monument, Colorado more than double the known diversity of fossil mammals from this rock unit, and provide a window into a diverse micromammal fauna that lived near Lake Florissant. Taxa first recorded here from the Florissant Formation include the lipotyphlans Centetodon magnus and Domnina cf. D. thompsoni, the lagomorph Megalagus brachyodon, and rodents Pelycomys, Eutypomys parvus, Ischyromys cf. I typus, I. cf. I. douglassi, and Adjidaumo minimus, all represented by dental material. We also describe isolated teeth of the artiodactyl Leptomeryx and the brontothere Megacerops. The mammalian fauna corroborates the Chadronian (latest Eocene) age of the Florissant Formation determined by others; Megalagus brachyodon suggests an age no older than Middle Chadronian. Several taxa reported here represent geographic range extensions. Eutypomys parvus is extended southeastward from southwestern Montana; ranges of Domnina thompsoni, Megalagus brachyodon, and Ischyromys douglassi are extended southwestward from western Nebraska; and ranges of Pelycomys, Ischyromys typus, and Adjidaumo minimus are extended slightly southwest from northeastern Colorado. Compared to other coeval North American faunas, the Florissant mammalian fauna is most similar to more northern faunas (including those of Montana, Nebraska, Wyoming, Saskatchewan, and NE Colorado). Geographically and faunally, the Florissant fauna appears to straddle the border between the Rocky Mountain and Great Plains Provinces defined by others, and appears consistent with weakened faunal provinciality during the Chadronian.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".