Redescription and revised taxonomy of Early Devonian (Emsian) acanthodians from New Brunswick and the Gaspé Peninsula, Quebec, Canada
Bibliographic record
Abstract
Devonian strata in eastern Canada, to the south of the Restigouche River in New Brunswick and north of Baie des Chaleurs in the Gaspé Peninsula, Quebec, are renowned for their vertebrate fossil faunas. Of the stem chondrichthyans, the taxa originally named as Ctenacanthus latispinosus Whiteaves, 1881, Diplodus problematicus Woodward, 1892, Gyracanthus incurvus Traquair, 1890, and Protodus jexi Woodward, 1892 have been reviewed and reassessed recently. In this work, we reassess ? Cheiracanthus costellatus Traquair, 1893 and Acanthodes semistriatus Woodward, 1892, long known from the Atholville beds, and also found in Gaspé. Specimens from the latter sites comprise fin spines and scales, and the material from the Atholville beds comprises the articulated holotypes for each species plus isolated spines and scales. We reassign ? Cheiracanthus costellatus to the diplacanthid Milesacanthus Young and Burrow, 2004 based on the distinctive structure of the fin spines, and scale morphology and histology. This represents the first record of Milesacanthus from the Americas. Acanthodes semistriatus was reassigned to Mesacanthus Traquair, 1888 in the early 1900s. We reaffirm this assignment based on the morphology and histology of dermal elements, and scapulocoracoid shape. We also describe rarer material from “nostolepid” and undetermined acanthodians, and reassess ? Ctenacanthus ? ornatus from Gaspé.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.006 | 0.005 |
| Science and technology studies | 0.003 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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 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".