Permian ammonoids from the Guadalupian (Wordian–Capitanian) of Las Delicias, Coahuila state, Mexico: new biostratigraphical and paleobiogeographical insights
Bibliographic record
Abstract
Abstract This work describes and discusses Permian ammonoid faunas collected in two stratigraphic sections from the Las Delicias Formation of Coahuila state, northern Mexico. The taxa identified comprise 18 species, including Demarezites quirozii new species, as well as Mexicoceras smithi (Miller and Furnish, 1940), a variety of Mexicoceras guadalupense (Girty, 1908) here upgraded to specific status. The systematic analysis of the species found allowed us to recognize two middle Permian faunal zones, represented in ascending order by the Waagenoceras dieneri - Adrianites elegans Biozone from the Wordian and the Timorites schucherti - Cibolites uddeni Biozone from the Capitanian. Thus, the relative age of the Las Difuntas-18 section is established as Wordian (middle Guadalupian), whereas the Las Manuelas I section is Wordian–Capitanian (middle–upper Guadalupian). Both ammonoid zones are correlated with those recorded in Guadalupian outcrops from the southern USA, northeastern Japan, and southern China. This faunal resemblance between Mexican ammonoids and those taxa reported in these regions (USA, Japan, and China) supports the proposal that during the middle Guadalupian there was a marine corridor through the Panthalassa Ocean, which could have connected the Paleotethys and North American regions. It should be noted that ammonoids of both studied sections from the Las Delicias Formation were correlated better with West Texas (USA) and British Columbia (Canada) faunas, which are included in the North American Realm. UUID: https://zoobank.org/60c6c43c-6536-4fbf-a372-c610bec86626
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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".