A Perithecial Sordariomycete (Ascomycota, Diaporthales) from the Lower Cretaceous of Vancouver Island, British Columbia, Canada
Bibliographic record
Abstract
A perithecial ascomycete, Spataporthe taylori gen. et sp. nov., represented by >70 sporocarps is preserved by cellular permineralization in marine carbonate concretions dated at the Valanginian-Hauterivian boundary (Early Cretaceous) from Vancouver Island, British Columbia, Canada. The spheroid perithecia with lumina 330–470 μm wide and 220–320 μm high are densely distributed and entirely immersed in the tissues of a coniferous leaf. The perithecial wall consists of an outer layer of large pseudoparenchyma and an inner layer of thin filamentous nature. Perithecial necks are incompletely preserved due to taphonomic abrasion; they have a bell-shaped chamber at the base and a narrow channel, with longitudinally aligned hyphae above. The basal chamber of the neck is filled with a plug of pseudoparenchyma, which subsequently disintegrates to form a peripheral collar; periphyses are present on the basal chamber walls. A pseudoparenchymatous hymenium lines the bottom of perithecia. Asci are clavate, with thinly tapered bases, and small (30–47 μm long and 12–20 μm wide at tip), ornamented with minute papillae. They become detached from the hymenium to float freely in the perithecium. No unequivocal ascospores were found, although smaller units are present in some of the asci. The combination of immersed perithecia with complex wall structure and a well-defined hymenium, absence of paraphyses, and persistent, detachable inoperculate asci is consistent with order Diaporthales of class Sordariomycetes. The small clavate asci are comparable to those found in family Gnomoniaceae. Perithecioid ascomata are rare in the fossil record, and bona fide perithecia are known with certainty only from the Early Devonian Rhynie Chert and Cenozoic amber. Spataporthe taylori contributes a well-characterized Early Cretaceous occurrence, which is also the oldest to date, to the scarce fossil record of the Sordariomycetes and a second taxon to the fungal flora of the locality, which also includes a basidiomycete. As the oldest representative of the Diaporthales, Spataporthe provides a minimum age (136 Ma) for the order and a direct calibration point for studies of divergence times in the ascomycetes.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.004 |
| Science and technology studies | 0.003 | 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) | 0.003 | 0.001 |
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".