The dentition of Omalodontiformes, the order of unusual Devonian stem-chondrichthyans
Bibliographic record
Abstract
The early chondrichthyan order Omalodontiformes from the late Early Devonian through to the Late Devonian is characterised by specific teeth. Unlike in most Devonian sharks, their bases are directed labially or are reduced and devoid of labial or lingual extensions. In this paper the complex history of investigation on the dermal skeleton of omalodontiforms is presented and the validity of the established taxa is revised. The dentition of an Emsian representative of this group, known from a single articulated specimen (NMBG 10127) and several isolated fin spines from Canada and previously, probably incorrectly, attributed to Doliodus, is distinctly heterodont. The nature of this heterodonty suggests that the two omalodontiform tooth-based genera described originally from the Middle/Upper Devonian Aztec Siltstone (Antarctica), viz. Portalodus and Anareodus, are in fact congeneric as their teeth represent different parts of the same jaw. Because the teeth of the Canadian specimen differ in important aspects from those of typical Doliodus and are generally similar to those of Portalodus, it probably should be placed in a new genus. Also, the validity of the distinction between Portalodus bradshawae and P. mannoliniae is considered questionable.
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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 | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 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".