A First Account of Organelle Preservation in Eocene Nonmarine Diatoms: Observations and Paleobiological Implications
Bibliographic record
Abstract
Abstract Post-eruptive lacustrine sediments that infill a Middle Eocene kimberlitic diatreme near Lac de Gras (Northwest Territories, Canada) have spectacular preservation of diatom microfossils. A single undiagnosed species belonging to the genus Aulacoseira is abundant in this material and reveals, in addition to the full complement of siliceous structures comprising the frustule, an array of soft parts that hitherto have been unavailable for study in diatoms of this age. These features include the velar complex, which lines the interior of valves, layered internal membranes, lamellate plastid fragments with pyrenoid-like inclusions, and extracellular mucilagenous bodies. Both ultrastructural and cytoplasmic characters have pronounced affinities with extant congeneric taxa, with an especially close resemblance to the resting cells observed in living Aulacoseira. These observations suggest that modern cellular organization and associated ecological adaptations were present early in the history of nonmarine aulacoseiroid diatoms, implying that prolonged evolutionary stasis has characterized the ecologically important genus Aulacoseira.
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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) | 0.003 | 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".