Histological skeletochronology indicates developmental plasticity in the early Permian stem lissamphibian <i>Doleserpeton annectens</i>
Bibliographic record
Abstract
Abstract Doleserpeton annectens is a small‐bodied early Permian amphibamiform, a clade of temnospondyl amphibians regarded by many workers to be on the lissamphibian stem. Most studies of this taxon have focused solely on its anatomy, but further exploration of other aspects of its paleobiology, such as developmental patterns, is critical for a better understanding of the early evolutionary history of lissamphibians. Here, we present a histological analysis of growth patterns in D. annectens that utilizes 60 femora, the largest sample size for any Paleozoic tetrapod. We identified pervasive pairs of closely spaced lines of arrested growth (LAGs), a pattern that indicates a marked degree of climatic harshness and that would result in two cessations of growth within a presumed single year. We documented a wide degree of variation compared to previous temnospondyl skeletochronological studies, reflected in the poor correlation between size and inferred age, but this observation aligns closely with patterns observed in extant lissamphibians. Furthermore, sensitivity analyses conducted by subsampling our dataset at more typical sample sizes for paleontological studies produced a wide range of results. This includes biologically improbable results and exceptionally well‐fit curves that demonstrate that low sample size can produce potentially misleading artifacts. We propose that the weak correlation between age and size represents developmental plasticity in D. annectens that typifies extant lissamphibians. Detection of these patterns is likely only possible with large sample sizes in extinct taxa, and low sample sizes can produce false, misleading results that warrant caution in drawing paleobiological interpretations from such samples.
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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 | 0.001 | 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) | 0.002 | 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".