Partial reconstruction and palaeoecology of Sphenophyllum costae (Middle Pennsylvanian, Nova Scotia, Canada)
Bibliographic record
Abstract
Recovery of a large, articulate portion of Sphenophyllum costae Sterzel from lower Cantabrian strata of the Sydney Coalfield, Nova Scotia, Canada, demonstrates that it is the largest sphenophyll yet known to inhabit clastic substrates of Euramerica.The specimen shows four orders of branching, with each axis characterized by whorls of leaves having distinct morphologies.Foliage clearly displays a tendency to become less divided on axes of ascending order.Furthermore, each branch order can be distinguished based on its internodal lengths and widths, which indicates that the species has a marked hierarchy of ramification similar to that found in the calamitalean sphenopsids.Axes of all orders apparently show epidogenetic followed by apoxogenetic growth patterns, which contributes to the high degree of heterophylly in the taxon.Comparison of axes and foliage of S. costae with other members of the genus reveals that sphenophylls from clastic substrates followed a fundamental ontogenetic pattern of growth and architecture, although subtle variations existed between taxa.Climber hooks are documented for the first time in the species, and the presence of these modified leaves supports the interpretation that S. costae formed dense, multi-branched thickets up to 2 m high comprising mutually supportive axes that rested upon, clung to, or entwined with adjacent axes.Palaeoecological and taphonomic evidence suggests that the plant formed as ground cover beneath arborescent medullosalean pteridosperms, and probably occupied well-drained (but moist) clastic habitats such as elevated channel margins or topographically raised hummocks on floodplains.
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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 | 0.001 | 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".