A comprehensive species sampling sheds light on the molecular phylogenetics of Calothecinae (Poaceae, Pooideae, Poeae): Evidence for a new subtribe and multiple genera within the <i>Chascolytrum</i> clade
Bibliographic record
Abstract
Abstract The circumscription of the grass subtribe Calothecinae has undergone several changes since its description. Currently, it comprises Chascolytrum and the recently described genera Laegaardia and Paramochloa. Here we evaluate the circumscription of Calothecinae and the recently proposed infrageneric classification of Chascolytrum based on a phylogeny with more comprehensive taxon and molecular marker sampling than in previous studies. We sampled all Calothecinae genera, all but one Chascolytrum species, two South American Trisetum s.l., and representatives of the subtribes Agrostidinae, Brizinae, Echinopogoninae, Koeleriinae, Phalaridinae, and Torreyochloinae within Poaceae tribe Poeae. We performed Bayesian and Maximum Likelihood analyses of four plastid DNA regions (atpF‐atpH, matK, rps16 intron, and trnL‐trnF) and two nuclear ribosomal regions (ITS and ETS). Our results revealed that neither Calothecinae nor Chascolytrum is monophyletic, as currently recognized, because Trisetum brasiliense and Trisetum bulbosum are nested within Chascolytrum. We include these two Trisetum species in Calothecinae as incertae sedis. Laegaardia and Paramochloa form a clade that is sister to the Chascolytrum + Trisetum clade, and based on morphological characters, we transfer the former to the new subtribe Paramochloinae. Our Chascolytrum phylogeny is better resolved and supported than in previous studies, and based on these results, we divide Chascolytrum into nine genera, including two new ones: Boldrinia (gen. nov.), Calotheca, Chascolytrum, Erianthecium, Lombardochloa, Microbriza, Poidium, Rhombolytrum, and Rosengurttia (gen. nov.). We provide a key to Calothecinae genera, descriptions of the genera, nomenclatural information, and keys to species of each genus. In addition, six new combinations are proposed.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".