Evolution toward asymmetrical gaits in Neotropical spiny rats (Rodentia: Echimyidae): evidences favoring adaptation
Bibliographic record
Abstract
The torch tail rat, Trinomys yonenagae Rocha, 1995 (family Echimyidae), is the morphologically most divergent of the spiny rats. In this study, we evaluate the hypothesis that gaits preferentially used by this species evolved as an adaptation to the desert-like dunes where they live. We filmed spontaneous locomotion of T. yonenagae, Trinomys albispinus minor Reis and Pessôa, 1995, and Proechimys cayennensis (Desmarest, 1817) with a high-speed camera. We detected, for each of the 323 cycles of the reference forelimb recorded, the kind of gait developed, the time lags between the touchdown of each pair of limbs, and the relative velocity. Trinomys yonenagae walked twice as fast as P. cayennensis and T. a. minor using mainly the asymmetrical transverse gallop, half-bounds, and bounds, while the other two species used mainly the lateral sequence walk. Gaits changed from symmetrical to asymmetrical with increasing velocity for T. yonenagae but not for the other species. We argue that the gait pattern found in T. yonenagae is autapomorphic, that its origin coincides with the shift to a desert-like habitat, and that this type of gait confers higher adaptive value to explore resources in open areas than the plesiomorphic pattern. Therefore, we conclude that it can be considered adaptive to life in the dunes.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".