Preservation of mandibular zinc in a beetle from the Eocene Kishenehn Formation of Montana, USA
Bibliographic record
Abstract
Fossil insects of the 46 million-year-old Coal Creek Member of the Kishenehn Formation exhibit exceptional preservation as evidenced by the preservation of color and the blood-derived pigment heme in a blood-engorged mosquito. In the present study, analysis of a fossil rove beetle (Coleoptera: Staphylinidae) from the Kishenehn Formation document preservation of zinc, a metal often used to harden the cutting surfaces of mandibles in extant insects, localized to the mandibles of the fossil insect. Scanning electron microscopy and energy-dispersive X-ray spectroscopy demonstrate that the carbonaceous bodies of preserved insects are physically homogeneous, composed primarily of carbon, and are distinct from the adjacent microbial mat within which the insects are thought to have been preserved. The microbial mat that covered the fossil insects is shown to consist of, in part, well-consolidated silicates. This thin layer, while completely transparent when wet, obscures the fossil when dry. The in situ preservation of components such as mandibular zinc and mosquito host blood-derived heme demonstrate that the carbonaceous bodies of Kishenehn Formation fossil insects contain some portion of their original contents. The thin layer of silicate-embedded mat may function to stabilize the fossil and its molecular components and may explain, in part, the exceptional preservation of the Kishenehn Formation fossils.
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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 | 0.001 | 0.001 |
| 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) | 0.001 | 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 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".