Wide-gauge sauropod trackways from the Early Jurassic of Sichuan, China: oldest sauropod trackways from Asia with special emphasis on a specimen showing a narrow turn
Bibliographic record
Abstract
An Early Jurassic sauropod dinosaur tracksite in the Lower Jurassic Zhenzhuchong Formation at the Changhebian site in Dazu County, Sichuan, is known to have yielded the trackway of a turning sauropod. A re-study of the site shows that all in all there are more than 100 tracks organized in at least three sauropod trackways. The narrow turn in one of the trackways is confirmed and analyzed in greater detail. All of the trackways show a wide gauge similar to Brontopodus -type trackways, but simultaneously exhibit high heteropody typical for Parabrontopodus -type trackways. The relative length of pes digits I, II and III is difficult to determine, but is suggestive of a primitive condition where digit I is less well developed than in Brontopodus . Thus far, they are the stratigraphically oldest sauropod trackways known from Asia being Hettangian in age. Previously, the trackway with the narrow turn was reported as the first turning sauropod trackway from Asia, but recently several other turning trackways have been reported suggesting that this behaviour is more commonly found than previously assumed and is now documented from the Early Jurassic to Late Cretaceous. Most of these examples show tight turns of between ~90 ° and as much as 180 ° suggesting that despite their large size sauropods could quite easily and abruptly change their direction of movement.
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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 | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 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".