The mid-Cambrian (Series 3, Guzhangian; Marjuman) trilobite <i>Deiracephalus</i> Resser, 1935, from western Newfoundland
Bibliographic record
Abstract
Species of Deiracephalus Resser, 1935, are rare elements in most Guzhangian (upper Marjuman) trilobite faunas of Laurentian North America, and are characterized by striking cephalic spinosity that includes very long genal and occipital or preoccipital glabellar spines. Almost all previous reports of the genus have assigned sclerites to two species, Deiracephalus aster (Walcott, 1916) and Deiracephalus unicornis Palmer, 1962. However, new material from the Shallow Bay Formation of western Newfoundland and restudy of type material from the southern Appalachians show that as many as eight species are present, although not all of them are sufficiently well known to be formally named. Deiracephalus aster and D. unicornis are restricted to their respective holotypes from the Conasauga Formation of Alabama; new species from the Shallow Bay Formation are Deiracephalus narwhali, Deiracephalus rhinocerotis, Deiracephalus dynastoides, and Deiracephalus phanaeus. Deiracephalus unicornis, D. narwhali, D. rhinocerotis, and a poorly known species from Nevada all possess preoccipital glabellar spines, and form an informal “unicornis group” of species. This group occurs high in the traditional Crepicephalus Zone (latest Guzhangian) and offers a potentially important means of biostratigraphic correlation. Species with occipital spines are older than the unicornis group and extend down into the Cedaria Zone as used traditionally in North America.
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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 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".