Dietary shifts in a group of early Eocene euarchontans (Microsyopidae) in association with climatic change
Bibliographic record
Abstract
Abstract Microsyopidae is a family of plesiadapiforms known from over 1500 stratigraphically controlled specimens from the southern Bighorn Basin of Wyoming spanning the first three million years of the early Eocene. The early Eocene is characterized by rapid fluctuations in climate during the period represented by this collection of microsyopids, making this an ideal sample to examine how climate may have influenced early stem primate biology, particularly diet. An evolving lineage of microsyopids is known from before, during, and after Biohorizon A, a faunal turnover event associated with a period of localized cooling. Dental topographic analysis (DTA) metrics quantify functional aspects of molars including curvature, complexity and relief, and covary with diet in extant taxa. Here, we use DTA to examine microsyopid dietary change over time, particularly in association with this cooling event. Our results suggest that microsyopids had molars that are functionally like extant insectivorous/omnivorous euarchontans. The earliest occurring species, Arctodontomys wilsoni , is characterized by molars that became more like modern insectivores over time. During Biohorizon A, A . wilsoni is replaced by A . nuptus , which has molars that are more like those of extant omnivores with a mixed diet including fruit. After Biohorizon A, A . nuptus appears more insectivorous, as is the later occurring Microsyops angustidens , which evolves from A . nuptus . Overall, we provide potential evidence for a causal scenario in which local climate change coincided with a dietary transition among microsyopids. Our results have implications for understanding how diet was a prime mover for the evolution of Primates.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".