Patterns of tooth development and replacement in captorhinid reptiles: a comparative approach for understanding the origin of multiple tooth rows
Bibliographic record
Abstract
Captorhinids are inherently interesting Paleozoic reptiles because they include the first terrestrial vertebrates to have multiple tooth rows on the maxilla and dentary. This may have been a key innovation that allowed captorhinids to diversify and disperse throughout the Permian Period of Pangea. We provide the first comparison of tooth development in captorhinids to determine how multiple rows of marginal teeth evolved within this clade. By comparing thin sections of multiple-rowed Captorhinus aguti from the Lower Permian of Oklahoma with the contemporaneous, single-rowed Captorhinus magnus, we provide evidence for variation in jaw growth, which establishes the number of tooth rows. Comparisons with the basal captorhinid Concordia cunninghami from the Upper Carboniferous of Kansas demonstrate that early captorhinids retained the typical amniote condition of replacing teeth in a manner similar to modern iguanian lizards. By comparing tooth development in C. aguti with other single-rowed captorhinids, we also demonstrate that the shedding of old teeth and the development of new teeth are not linked developmental processes in captorhinids. Instead, the fates of older generations of teeth are entirely dependent on their proximity to the lingual surface of the dentary where the tooth-producing organ, the dental lamina, would have been present. These peculiar features of the dentitions of captorhinids make them model taxa for examining patterns of tooth development and replacement.
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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 | 0.000 |
| 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 | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".