Unusual preservation of the trace fossil <i>Conostichus</i> in middle Silurian carbonate facies of Indiana, USA
Bibliographic record
Abstract
The long-ranging, plug-shaped ichnofossil Conostichus, attributed to solitary polypoid cnidarians, is most commonly described in the Paleozoic from fine-grained siliciclastic sediments, with few descriptions from carbonate settings. The few described examples of putative Conostichus preserved in carbonate sedimentary rocks of Paleozoic age are essentially conical masses lacking recognizable external radial or longitudinal structures. Herein, we describe the occurrence of well-preserved examples of this ichnogenus within middle Silurian (Wenlock: Sheinwoodian) carbonate sedimentary rocks of the Massie Formation from southeastern Indiana, USA. These specimens represent isolated apical discs of Conostichus with prominent radiating physal impressions displaying duodecimal symmetry. Interestingly, well-preserved specimens co-occur with relatively poorly preserved (“typical carbonate”) specimens. The factors responsible for this unusual taphonomic state are unclear, but the most likely explanation is that exceptionally preserved specimens represent burrows that were somehow infilled, at least in their apical terminations, with fine-grained carbonate sediment, enhancing preservational fidelity. In contrast, other burrows had their apical regions passively filled with larger carbonate particles that could not preserve fine details. This occurrence indicates that early Paleozoic carbonate sediments are capable of preserving Conostichus, and potentially other ichnofossils, in similar modes to later Paleozoic siliciclastic deposits.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".