Frog origins: inferences based on ancestral reconstructions of locomotor performance and anatomy
Bibliographic record
Abstract
Frogs are the most species-rich and ecologically diverse group of amphibians and are characterized by a unique body plan including long legs, elongated ilia, and fused caudal vertebrae.Stem anurans such as Triadobatrachus or Czatkobatrachus have been suggested to have used jumping or hopping as part of their locomotor repertoire based on their anatomy.The earliest known true frog, Prosalirus bitis was suggested to have been a proficient jumper.However, data on jumping performance in frogs have never been used to attempt reconstruction of ancestral features at the base of the radiation.Here we provide data on jumping performance (forces and acceleration) in 20 species of extant frogs including representatives of most of the early radiating clades.We next use ancestral character value inferences to assess ancestral features.Our analyses suggest that frog ancestors were of small to medium size, had relatively short limbs, produced rather low jump forces, yet were capable of relatively high acceleration.Given the short limbs and low forces, the unique frog bauplan with a reduced vertebral column and a mobile ilio-sacral joint may not have been an adaptation for powerful jumping.
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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 | 0.002 | 0.007 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.003 | 0.002 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.002 |
| Insufficient payload (model declined to judge) | 0.007 | 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".