A new paraclupeid fish (Clupeomorpha, Ellimmichthyiformes) from a muddy marine pro-delta environment: middle Cenomanian Dunvegan Formation, Alberta, Canada
Bibliographic record
Abstract
A black marine mudstone in allomember A of the middle Cenomanian Dunvegan Formation, Alberta, yielded a well-preserved, deep-bodied fish skeleton attributable to a new genus and species, Tycheroichthys dunveganensis, in the Paraclupeidae (Clupeomorpha, Ellimmichthyiformes). This new taxon appears most closely related to members of the subfamily Paraclupeinae, which includes largely freshwater and estuarine or marginal marine species known from South and Central America and China. The Dunvegan Formation represents a large delta complex deposited in the Western Interior Seaway at about 65°N, where mean sea water temperature may have been about 10 °C. The specimen was found about 60 km from the contemporaneous shoreline, and, in life, apparently inhabited a shallow, muddy pro-delta environment characterized by high turbidity and variable salinity. The fish may have died when it was engulfed by brackish floodwater that also introduced suspended mud that rapidly buried the body, preventing physical disarticulation of the skeleton. River outflow probably produced a salinity- and density-stratified water column that limited oxygen transfer to the sea floor, leading to dysaerobic bottom water and an absence of scavengers. High terrestrial phytodetrital content of the sediment also favoured anaerobic conditions that limited bacterial decay.
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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".