Triassic ichthyopterygian assemblages of the Svalbard archipelago: a reassessment of taxonomy and distribution
Bibliographic record
Abstract
Ichthyopterygians were amongst the most specialised lineages of secondarily aquatic amniotes; however, their origin and initial radiation remain obscure. The stratigraphically oldest and phylogenetically most basal taxa have been found in Early–Middle Triassic deposits throughout the northern hemisphere, but one of the earliest documented and arguably most important localities is the High Arctic Svalbard archipelago. Like many classic palaeontological sites, the Svalbard Triassic fossil-bearing horizons are plagued by inconsistent geological interpretations and taxonomic classifications. To resolve these conflicts, a comprehensive revision of the various ichthyopterygian assemblages was undertaken. The fossils were found to be distributed through three sequential rock units: the Olenekian Vikinghøgda Formation (six discernible taxa distributed over two distinct horizons), Anisian lower Botneheia Formation (two taxa) and the Ladinian–Carnian Blanknuten Member of the Botneheia Formation–Tschermakfjellet Formation (five taxa). Unfortunately, many of the specimens are non-diagnostic at species-level, although they do contribute a cohesive picture of marine faunal successions during the Early–earliest Late Triassic. Indeed, the Svalbard archipelago has produced one of the most diverse Early Triassic ichthyopterygian assemblages known worldwide, but is comparatively species poor throughout the early Middle Triassic, perhaps due to sampling biases.
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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 | 0.005 | 0.002 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| 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".