Biostratigraphy and paleoecology of the trilobite faunas from the Mount Clark and Mount Cap formations (early and middle Cambrian), eastern Mackenzie Mountains, northwestern Canada
Bibliographic record
Abstract
Abstract Lower and middle Cambrian strata of the eastern Mackenzie Mountains, Northwest Territories, Canada, were deposited in a semi-enclosed basin along the eastern flank of the Mackenzie Arch. The Mount Clark Formation is predominantly composed of nearshore sandstone and is overlain by deeper water siltstone, mudstone, and carbonates of the Mount Cap Formation. The contact between these formations is interpreted as a flooding surface. Trilobite biostratigraphy indicates the presence of the traditional upper Olenellus through Glossopleura zones (Cambrian Series 2, Stage 4–Miaolingian, Wuliuan) and suggests the flooding surface is diachronous, spanning the Dyeran-Delamaran boundary. Above the Olenellus Zone, the Amecephalus arrojosensis - Eokochaspis nodosa Zone, the new Aitkenaspis keelensis Zone, the new Albertelloides mischi Zone, and the Glossopleura walcotti Zone are recognized. Whereas the older zones are comparable to those in other areas of Laurentia, the trilobite faunas in the Albertelloides mischi and Glossopleura walcotti zones show a greater abundance of zacanthoidids and dolichometopids. They also have a lower diversity of ptychoparioids and oryctocephalids, and lack agnostoids, eodiscoids, dorypygids, and ogygopsidids. This suggests that zacanthoidids and dolichometopids were able to tolerate conditions that were unfavorable to the other groups, probably related to semi-restricted conditions in the basin. Four endemic species exhibit characteristics that are considered paedomorphic. This developmental process took place in three separate lineages, suggesting that heterochrony was also environmentally provoked. New taxonomic names are authored by Handkamer and Pratt. New genera are Eobathyuriscus , Sahtuia , Mexicaspidella Aitkenaspis , Dodoella , and Mackenzieaspis . New species are Bolbolenellus dodoensis , Eobathyuriscus mackenziensis , E . macqueeni , Glossopleura youngi , Sahtuia carcajouensis , Aitkenaspis keelensis , Albertelloides eliasi , Dodoella kobayashii , Mackenzieaspis parallelispinosa , and M . divergens . UUID: http://zoobank.org/a10a2470-853c-4ce8-bf62-7de1d2c99fab .
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".