Constrained variation in the internal architecture of avian wing bones
Bibliographic record
Abstract
Abstract Extant birds exhibit remarkable ecological disparity accompanied by widespread skeletal convergence driven by functional adaptation. Investigations of morphofunctional associations with ecological factors have frequently focused on the external morphology of avian wing bones; however, the extent to which such associations also apply to the internal structure of the wing skeleton remains understudied. Here, we investigate disparity of the internal epiphyseal and diaphyseal structure of the avian humerus and ulna, and explore its correlates with ecology. Our dataset of 140 species spans extant bird diversity, and demonstrates that the internal structure of avian wing bones exhibits limited ecological signal beyond expected secondary trends related to flightlessness and marine habits. Our work instead shows that variation is primarily determined by body size, suggesting that functional constraints on internal wing bone structure imposed by flight are essentially universal across flying birds irrespective of most ecological habits and flight styles. Despite this broad lack of ecological signal, distinctive aspects of forelimb internal structure may facilitate the identification of flightless bird taxa in the fossil record.
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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 | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 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) | 0.002 | 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".