An early cladoxylopsid with complex vascular architecture: <i>Paracladoxylon kespekianum</i> gen. et sp. nov. from the Lower Devonian (Emsian) of Quebec, Canada
Bibliographic record
Abstract
PREMISE: Cladoxylopsids, one of the first lineages with complex organization to rise from the plexus of structurally simple plants that comprised the earliest euphyllophyte floras, are moniliformopsid euphyllophytes. They formed Earth's earliest forests by the Middle Devonian and are thought to have given rise to the equisetopsids and probably some fern lineages. The Lower Devonian (Emsian) Battery Point Formation (Quebec, Canada) contains previously unrecognized cladoxylopsids preserved anatomically. One of these provides new data on structural evolution among euphyllophytes and is described here. METHODS: The anatomy and morphology of permineralized axes of the new plant were studied with light and electron microscopy on sections produced using the cellulose acetate peel technique. Morphological comparisons and phylogenetic analysis were used for taxonomic placement of the plant. RESULTS: The plant represents a new species, Paracladoxylon kespekianum Chu et Tomescu, gen. et sp. nov., that has tracheids with modern-looking bordered pits and the complex cauline vascular architecture characteristic of the genus Cladoxylon. Its dissected ultimate appendages have complex regular taxis and a pattern of vascularization that suggests bilateral symmetry. CONCLUSIONS: Paracladoxylon kespekianum is one of the largest Early Devonian euphyllophytes, among the oldest representatives of the cladoxylopsid group, and older than any species of the closely related Cladoxylon by at least 35 million years. It is also one of the oldest anatomically preserved representatives of the cladoxylopsid group. Its anatomical organization pushes the rise of complex vascular architecture among moniliformopsid euphyllophytes deeper in time than previously recognized.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| 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".