True<i>Dalmanella</i>and taxonomic implications for some Late Ordovician dalmanellid brachiopods from North America
Bibliographic record
Abstract
Examination of topotype material of the type species of Dalmanella, D. testudinaria, from the Hirnantian strata of Borenshult, southern Sweden, revealed several diagnostic characters that distinguish the type species from some common North American species assigned previously to the genus. The typical Dalmanella testudinaria has a consistently developed, primary medial interspace in the dorsal valve, a cardinal process with an invariably bilobed myophore, punctae of two distinctly different sizes, and a lack of aditicules. In contrast, many Late Ordovician species from North America, such as ‘Dalmanella’ meeki and ‘Dalmanella’ multisecta from the Cincinnati type area, consistently have a dorsal medial costa, with a strong tendency to develop aditicules and a trilobate cardinal process. This study confirms the previous notion of many authors that true Dalmanella testudinaria, or the genus as a whole, is either rare or entirely absent in North America. Typical Dalmanella was predominant in cool-water depositional environments (such as the Hirnantia Fauna), whereas the North American dalmanellids (e.g. Cincinnati-type ‘Dalmanella’, Paucicrura, and Diceromyonia) were most abundant and diverse in tropical, epicontinental sea settings. A clear definition of the true Dalmanella, therefore, has important implications for the study of Late Ordovician–Early Silurian brachiopod evolution, paleoecology, and paleobiogeography.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| 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".