A vertebrate microsite from a marine-terrestrial transition in the Foremost Formation (Campanian) of Alberta, Canada, and the use of faunal assemblage data as a palaeoenvironmental indicator
Bibliographic record
Abstract
Vertebrate microfossil assemblages contain abundant fossil material of small and large bodied animals recruited from the local paleocommunity that can provide important information for reconstructing regional paleoecology. The Foremost Formation is the oldest unit of the Belly River Group, and records the transition from the fully marine shales of the Pakowki Formation to the non-marine strata of the relatively well-sampled Oldman and Dinosaur Park formations. Although the Foremost Formation has relatively limited exposure and vertebrate fossil material is not abundant, it does contain some important early records of major vertebrate clades from Laramidia (e.g. ceratopsids, pachycephalosaurids).Here we document a new microfossil locality from the upper part of the formation that shows a transitional assemblage containing an abundance of terrestrial forms such as dinosaurs and other sauropsids, while still showing considerable marine influence. The proportion of marine taxa at this site is reduced relative to most sites known from the Foremost Formation, though much higher than more terrestrial sites of the overlying Oldman Formation. In addition to filling a gap in our understanding of this paleoenvironmental transition, this new site preserves two particularly significant specimens: a large, complete, cephalic spine of the hybodont shark Hybodus, and jaw fragments from the ratfish Elasmodus. This represents the first known complete cephalic spine of a hybodont shark from the Cretaceous of Alberta. The ratfish jaw fragments represent the first published record of this group from the Foremost Formation, further increasing our knowledge of chondrichthyan diversity in the Western Interior Seaway. Comparisons of this site to other microsites from the Campanian of Alberta demonstrate the utility of certain key groups, such as lissamphibians and chondrichthyans, in determining paleoenvironments from Mesozoic and Cenozoic vertebrate microsite assemblage data.
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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 | 0.001 | 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 | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".