A comprehensive sampling of species sheds light on the molecular phylogenetics of Calothecinae (Poaceae, Pooideae): evidence for a new subtribe and multiple genera within the Chascolytrum clade
Bibliographic record
Abstract
The circumscription of subtribe Calothecinae has undergone several changes since its description. Currently, three genera are considered in the subtribe: Chascolytrum, Laegaardia and Paramochloa, although no phylogenetic evidence for the placement of the two last genera was published so far. In this study we aim to evaluate the circumscription of Calothecinae and the infrageneric classification recently proposed for Chascolytrum using a more comprehensive sampling of taxa and molecular markers. We included species of all genera of Calothecinae, plus two South American species of Trisetum s.l. that have been suggested to be related to Chascolytrum, and representatives from subtribes Agrostidinae, Echinopogoninae, Brizinae, Torreyochloinae, Phalaridinae and Koeleriinae. We performed Bayesian and Maximum Likelihood analyses using a total of six molecular markers, including four plastid DNA regions (atpF-atpH, matK, rps16 intron, and trnL-trnF) and two ribosomal nuclear regions (ITS and ETS). Our results revealed that neither Calothecinae nor Chascolytrum are monophyletic considering their last circumscription. Trisetum brasiliense and T. bulbosum appeared nested to Chascolytrum, and are formally included in Calothecinae as incertae sedis. More studies are needed to confirm their taxonomic position. Based on morphological characters, Laegaardia and Paramochloa are transferred to the new subtribe Paramochloinae, and Chascolytrum is splitted in nine different genera, of which two are newly described: Boldrinia (gen. nov.), Calotheca, Chascolytrum, Erianthecium, Lombardochloa, Microbriza, Poidium, Rhombolytrum, and Rosengurttia (gen. nov.).
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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 | 0.000 |
| 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".