Early Tertiary<i>Chamaecyparis</i>Spach from Axel Heiberg Island, Canadian High Arctic
Bibliographic record
Abstract
Exquisitely preserved fossil remains of Chamaecyparis Spach (Cupressaceae) have been recovered from Middle Eocene sediments of the Buchanan Lake Formation, Eureka Sound Group, of Axel Heiberg Island, Canadian Arctic Archipelago. Foliage consists of flattened, frondlike sprays considered typical for the genus. Leaves are decussate, scalelike, imbricate, appressed, and persistent. Seed cones are globose to subellipsoid, are borne on leafy peduncles, and bear 812 woody, peltate cone scales in a decussate arrangement. Seeds are two or more per scale, and winged. Within the genus, this fossil is most similar to extant Chamaecyparis pisifera (Siebold & Zucc.) Endl. of Japan, although the suite of features found in the fossil does not occur in any single living species of the genus. These fossil remains are assigned to a new species, Chamaecyparis eureka Kotyk sp. nov. A review of the fossil record indicates that Chamaecyparis eureka is the oldest known member of the genus, as the Late Cretaceous taxon Chamaecyparis corpulenta (Bell) McIver appears most closely related to Cupressus nootkatensis D. Don [= Chamaecyparis nootkatensis (D. Don) Spach], and should therefore be excluded from the genus Chamaecyparis. As revealed by the fossil assemblages of the Buchanan Lake deposits, Chamaecyparis was an uncommon constituent of lowland, swampforest communities growing at high paleolatitudes (about 78°N) during a period of global warmth prior to the onset of global climatic deterioration that led to Late Cenozoic glaciation. It was one of the few evergreen taxa in a largely deciduous broad-leaved and coniferous vegetation of early Tertiary regions in the far north.Key words: fossil, Tertiary, Chamaecyparis, Cupressaceae, Arctic, Canada.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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 teacher head, 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".