TAPHONOMIC VARIANCE BETWEEN MARATTIALEAN FERNS AND MEDULLOSAN SEED FERNS IN THE CARBONIFEROUS MAZON CREEK LAGERSTÄTTE, ILLINOIS, USA
Bibliographic record
Abstract
Abstract Marattialean ferns and medullosan seed ferns are two dominant groups in late Carboniferous lowland tropical floras. Differences in their foliage suggest that some seed ferns may have had a higher preservation potential when compared to marattialean ferns. Should this be accurate, it would suggest that when the two groups are found together, marattialean ferns would be better preserved and potentially better represented than seed ferns. Such taphonomic biases would have direct implications for evaluating plant diversity in deep time. To evaluate this hypothesis, we analyzed more than 880 fern and seed fern fossils encased in siderite (FeCO3) concretions from the ∼ 308 Ma Mazon Creek Lagerstätte to test if seed fern foliage is better preserved than fern foliage with respect to taxonomic information. For comparative purposes, we conducted a series of decay experiments on two modern ferns and a cycad (the last providing a seed fern analogue) for 160 days. Despite anatomical and compositional differences, fossil analyses demonstrate that ferns and seed ferns are equally well preserved in the Mazon Creek Lagerstätte with respect to venation, which represents one of the most important taxonomic characters of the flora. The decay experiments support this conclusion: despite having a more robust leaf, cycad leaves decayed at a similar rate to the thinner, more hypothetically fragile ferns. Together, our results indicate that our ability to discriminate within and between ferns and seed ferns is not biased by differential preservation in the Mazon Creek flora.
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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 | 0.001 | 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".