Genetic Assessment of Taxonomic Uncertainty in Painted Turtles
Bibliographic record
Abstract
There is ongoing uncertainty regarding the taxonomic status of Painted Turtles (genus Chrysemys). Most recently, a phylogenetic analysis of the mitochondrial DNA control region (mtCR) resulted in the elevation of a subspecies to the species level, resulting in two species being tentatively, but not universally, accepted: Chrysemys dorsalis and C. picta, the latter encompassing the three remaining subspecies. Here, we used expanded range-wide sampling and character data from PAX-P1 nuclear intron (n = 127) and mtCR (n = 259) to further investigate taxonomic uncertainty and paleogeography of Painted Turtles. We found five mtCR characters that distinguished C. dorsalis from C. picta; no such evidence was found in PAX-P1. Chrysemys dorsalis formed a monophyletic group in the reconstructed phylogenetic trees, whereas there was no genetic evidence for the distinctiveness of the three C. picta subspecies. The mtCR network showed C. dorsalis and C. p. bellii to each form relatively distinct clusters, whereas no clustering by morphotype was found in the PAX-P1 network. Lower levels of haplotypic diversity across the range of C. p. bellii are consistent with recent postglacial expansion to the west; however, observed mismatch distributions were multimodal, which does not indicate population expansion. Overall, the addition of nuclear DNA character data and expanded sampling support the tentative designation of C. dorsalis and C.picta (encompassing C. p. picta, C. p. bellii, and C. p. marginata) as separate species. Yet, lack of accompanying morphological data and potential for oversplitting due to targeting only individuals within the core of morphotype ranges suggests that further study is warranted.
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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 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.003 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.000 | 0.001 |
| 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".