New species of Picea A. Dietrich (Pinaceae) from the middle Eocene of Axel Heiberg Island, Arctic Canada
Bibliographic record
Abstract
The discovery of several hundred fertile and vegetative remains of three new species of Picea A. Dietrich (P. suerdrupii, P. nansenii, P. palustris) from the middle Eocene (45 Myr) sediments of the Buchanan Lake Formation on eastern Axel Heiberg Island, Canadian High Arctic provides a basis for re-assessment of the fossil record of the genus and evaluation of the morphological variability in this taxon. The identification and classification of extant Picea is based on a whole-tree concept that in turn is based on the importance of one or more of the following features: cross-sectional shape of the leaves; degree of pubescence of the twigs; arrangement of the stomata on the leaves; colour of the leaves and new growth shoots; length and shape of the cones; shape and degree of pubescence of the buds; and cone-scale morphology. However, the degree of intraspecific variability of these characters is poorly understood and has contributed a great deal towards our general inability to interpret reliably the evolutionary history and phylogenetic relationships within the genus. Examination of the bracts of the Axel Heiberg spruces and all extant species of Picea indicates that bract morphology is distinctive for each species and useful for species circumscription. These data allow the genus to be divided into two broad morphological groups that are in general agreement with topologies based on molecular data.
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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 | 0.003 | 0.002 |
| 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) | 0.001 | 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".