Shape variation in the talus and medial cuneiform of chimpanzees and bonobos
Bibliographic record
Abstract
Abstract Objectives Bonobos and chimpanzees do not differ from one another in overall frequencies of arboreality versus terrestriality as much as once thought. Thus, at a broad level, one would predict that there is little difference in foot morphology among Pan taxa. However, behavioral data suggest that bonobos more often use smaller diameter substrates (<10 cm) when climbing whereas western chimpanzees frequently climb larger diameter (>15 cm) substrates. This study tests the hypothesis that if Pan medial cuneiform and talus morphology reflects these substrate preferences, then the morphology of these bones should favor hallucial grasping in bonobos and an inverted foot set in western chimpanzees. Materials and Methods Three‐dimensional geometric morphometric (3DGM) methods were used to explore shape variation in 126 talus and 127 medial cuneiform 3D surface models acquired from 108 chimpanzees (24 western, four Nigeria‐Cameroon, 33 central, 32 eastern, and 15 captive unknowns) and 22 bonobos Results The shapes of the talus and medial cuneiform in Pan covary as a functional unit emphasizing hallucial grasping with a less inverted foot set in bonobos and a more inverted foot set with a less abducted hallucial set in western chimpanzees. Other chimpanzee subspecies fall between these two extremes. Discussion Bonobo and western chimpanzee medial cuneiform and talus shapes are consistent with their differing preferences for using smaller and larger diameter substrates, respectively, when vertically climbing. These results suggest that even among closely related taxa, foot, hand, and other postcranial anatomy may be fine‐tuned for specific locomotor behaviors or preferences.
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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 | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 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) | 0.001 | 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".