The megathermal ant genus <i>Gesomyrmex</i> (Formicidae: Formicinae), palaeoindicator of wide latitudinal biome homogeneity during the PETM
Bibliographic record
Abstract
Abstract The Palaeocene–Eocene Thermal Maximum (PETM) is one of the most important Cenozoic climatic events shaping modern biodiversity, yet reconstructions of its palaeobiomes remain controversial. Here we describe Gesomyrmex gallicus sp. nov., a new, extinct species of the ant genus Gesomyrmex Mayr, 1868, based on minor and major workers preserved in the early Eocene amber of Oise, France. Although there are only seven known extant species in the genus, all confined to warm and humid forests of SE Asia, the fossil record of Gesomyrmex indicates that the genus once radiated across Eurasia. The new species therefore provides direct evidence that this radiation likely co-occurred with the PETM. This observation constrains palaeoclimatic reconstructions of the Early Eocene by requiring the presence of an extensive, homogeneous and interconnected rainforest-like biome across palaeo-Eurasia, a scenario otherwise corroborated by pollen assemblages. The phases of regression of warm and humid forests and the widening of dry biomes probably occurred later during the Eocene, in between hyperthermals, and were probably less extensive than some computer models predicted.
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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 | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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".