The biomechanical significance of bifurcated cervical ribs in apatosaurine sauropods
Bibliographic record
Abstract
Bifurcated cervical ribs have evolved infrequently in dinosaurs. Previously documented examples include those in abelisaurid theropods, leptoceratopsid ceratopsians, and turiasaurian sauropods. In apatosaurine sauropods a spectrum of cervical rib morphologies exists, from cervical ribs with small dorsal processes extending from the shafts to completely bifurcated cervical ribs. Similar dorsal processes are present in the dicraeosaurid Dicraeosaurus. The presence of dorsal processes and bifurcated cervical ribs suggests that the hypaxial neck muscles that inserted on the cervical ribs were oriented in divergent directions. In all the dinosaurian examples we have found, the cervical ribs are maximally bifurcated in the middle of the cervical series. We hypothesize that bifurcated cervical ribs are traces of diverging neck muscles that provided improved control in the middle of the neck, at some distance from both the head and the trunk.
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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) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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; both teacher heads agree on what is shown here.
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".