Ultrastructure of <i>Olkasia polycarbonata</i> (Euglenozoa, Euglenida) demonstrates cytoskeletal innovations associated with the feeding and flagellar apparatuses
Bibliographic record
Abstract
Euglenids are flagellates with diverse modes of nutrition, including the photosynthetic Euglenophyceae, which acquired plastids via secondary endosymbiosis with green algae, and a diverse assemblage of predators of bacteria and other microeukaryotes. Most heterotrophic euglenids have never been cultivated, so their morphology remains poorly characterized and limited to only a few studies. "Ploeotids" are a paraphyletic group representing much of the diversity of heterotrophic euglenids and are characterized by their feeding apparatus and a rigid pellicle of 10-12 longitudinally arranged strips. Ploeotid-like euglenids gave rise to the Spirocuta, a large clade of heterotrophic and photosynthetic euglenids defined by a flexible pellicle of helically arranged strips. Using single-cell approaches, we report the first ultrastructural characterization of Olkasia polycarbonata, a ploeotid that is consistently positioned as the sister lineage to the Spirocuta in multigene phylogenetic analyses. O. polycarbonata shares several morphological characteristics with members of Spirocuta, such as prominent swellings on the paraxonemal rods and a robust feeding apparatus consisting of rods and vanes. These morphological traits are consistent with the phylogenetic position of O. polycarbonata and demonstrate an increase in cytoskeletal complexity that occurred prior to the key strip duplication event in the most recent common ancestor of Spirocuta.
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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 | 0.000 | 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) | 0.001 | 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".