First chimaeroid fish egg capsule (Chondrichthyes, Holocephali, Chimaeriformes) from upper Eocene Carmanah Group strata, West Coast of Vancouver Island, British Columbia, Canada
Bibliographic record
Abstract
A rare and new fossil chimaeroid fish egg capsule specimen was discovered in marine lower Carmanah Group strata at Botanical Beach, Vancouver Island, British Columbia, Canada. The age of the egg capsule is late Eocene (35.35 ± 0.12 Ma), determined by strontium isotope dating and foraminifera biostratigraphy. The new specimen is a three-dimensional mold in calcareous sandstone and is herein described as a new ichnospecies, Vaillantoonia jonasoni. Based on several morphological characteristics (e.g., spindle-like body shape, widened tail tip, narrow anterior spatula-shaped beak, and numerous lateral membrane costae), the new fossil is similar to the egg capsules of extant Rhinochimaeridae (Chimaeriformes). Following earlier discoveries of Vaillantoonia alaskana (Brown, 1946) (middle Oligocene, Alaska), Vaillantoonia sp. 1 (Oligocene, Washington), and Vaillantoonia sp. 2 (upper Eocene, Oregon), this is the fourth Paleogene chimaeroid egg capsule from the Pacific Northwest. The new form clearly differs from the other previously described Pacific Northwest specimens and from other rhinochimaerid-like egg capsules. The base of the Carmanah Group section at Botanical Beach is eroded, containing conglomerate and sandstone with diagnostic upper Eocene middle–upper bathyal foraminifera. The upper part of the section contains massive gravity flow sands that buried the new egg capsule (later bound and preserved by migrating carbonates in solution). Carmanah Group strata at Botanical Beach record part of a complex tectonic history within an elongate forearc basin similar to other Eocene/Oligocene North American West Coast basins from which rhinochimaerid egg capsule fossils are known.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".