Late Smithian (Early Triassic) ammonoids from the uppermost Lusitaniadalen Member (Vikinghøgda Formation), Svalbard.
Bibliographic record
Abstract
Abstract Late Smithian (Early Triassic) ammonoids from a single carbonate concretion in the uppermost Lusitaniadalen Member ( Fish Niveau , Vikinghøgda Formation) at Stensiöfjellet, Spitsbergen, are studied and compared with similar assemblages from other areas. Late Smithian ammonoid assemblages are characterised worldwide by low diversity and predominance of the family of the prionitids. The species identified here are: Wasatchites tridentinus, Wasatchites cf. distractus, Anasibirites kingianus, Arctoprionites nodosus, Arctoprionites resseri and Xenoceltites subevolutus. The group named Wasatchites spp. indet. includes juveniles of the genus Wasatchites which were hard to identify at species level. Two new taxa are proposed: Arctoceras sp. nov and Gen. et sp. nov. (prionitid). Difficulties in taxonomic identification have arisen due to the high intraspecific variation and the immature stage of most of the specimens. The assemblage is discussed in a broader context to infer information about the ecological, biostratigraphic and palaeogeographic implications. The good preservation and lack of evidence of transportation suggest deposition in a low energy environment, in accordance with sedimentological observations. The lack of true juveniles and adult individuals may indicate separation of the groups until maturity and high juvenile mortality. From a biostratigraphic point of view, the Spitsbergen fauna is in good agreement with other assemblages within and outside the Boreal Realm. Most similarities, as already pointed out in previous literature, are with the Boreal Canadian Province, though the studied fauna seems to present some peculiarities. The presence of newly recorded taxa such as Wasatchites cf. distractus and Arctoprionites resseri that are more typical for lower latitudes may suggest more marked connections with warmer water than expected (in a similar fashion as in Canada). The finding of arctoceratids at this level confirms their range up to the tardus Zone.
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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 | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".