Diving dinosaurs? Caveats on the use of bone compactness and pFDA for inferring lifestyle
Bibliographic record
Abstract
Abstract Measures of bone compactness in amniote tetrapods of varying lifestyle were used to infer that two spinosaurid dinosaurs ( Spinosaurus aegyptiacus , Baryonyx walkeri ) were diving “subaqueous foragers,” whereas a third spinosaurid ( Suchomimus tenerensis ) and other sampled nonavian dinosaurs were non-diving terrestrial feeders entering water only as waders. We outline shortcomings in this analysis that involve bone compactness sampling and measurement, lifestyle categorization, the inclusion and exclusion of taxa in the dataset, and flawed statistical methods and inferences. These many shortcomings undermine the evidence used to conclude that two spinosaurid taxa were avid divers. Bone compactness indices remain a valuable tool for interpretation of lifestyle in extinct species when based on sound dataset composition, robust statistical analysis, and consilience with evidence from functional, biomechanical, or paleoenvironmental considerations.
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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 | 0.141 | 0.360 |
| Meta-epidemiology (narrow) | 0.002 | 0.001 |
| Meta-epidemiology (broad) | 0.002 | 0.002 |
| Bibliometrics | 0.004 | 0.004 |
| Science and technology studies | 0.002 | 0.007 |
| Scholarly communication | 0.005 | 0.004 |
| Open science | 0.008 | 0.003 |
| Research integrity | 0.002 | 0.004 |
| Insufficient payload (model declined to judge) | 0.005 | 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; 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".