Reassessment of historic ‘microsaurs’ from Joggins, Nova Scotia, reveals hidden diversity in the earliest amniote ecosystem
Bibliographic record
Abstract
Abstract ‘Microsaurs’ are traditionally considered to be lepospondyl non‐amniotes, but recent analyses have recovered a subset of ‘microsaurs’, the fossorially adapted Recumbirostra, within Amniota. This novel conclusion highlights the need for additional work to evaluate these competing hypotheses with the aim of refining the phylogenetic position of ‘microsaurs’. Of particular importance in this regard is the placement of potential close relatives of recumbirostrans to determine whether they support an early, stepwise acquisition of the derived morphology seen in recumbirostrans for a fossorial lifestyle, or whether this morphology is the result of evolutionary convergence. Asaphestera intermedia is part of a diverse ‘microsaur’ assemblage preserved at the famous Pennsylvanian Joggins locality in Nova Scotia, Canada. As part of a broader exploration of ‘microsaur’ taxonomy, we find that the material assigned to this taxon is a composite of a synapsid (herein Asaphestera platyris ), indeterminate tetrapod material named ‘ Hylerpeton ’ intermedium (a nomen dubium not referable to Hylerpeton ), and the newly recognized recumbirostran Steenerpeton silvae gen. et sp. nov. Further, Archerpeton anthracos from the same site must at present be considered a nomen dubium and may or may not be a ‘microsaur’. Recognition of Asaphestera platyris as a synapsid provides the earliest unambiguous evidence of ‘mammal‐like reptiles’ in the fossil record.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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 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".