Morphology and phylogenetic position of two novel marine gregarines (Apicomplexa, Eugregarinorida) from the intestines of North‐eastern Pacific ascidians
Bibliographic record
Abstract
Eugregarine apicomplexans parasitize marine, freshwater and terrestrial invertebrates, and have lifecycles involving trophozoites (feeding stages) with complex morphologies and behaviour. The genus Lankesteria refers to marine aseptate eugregarines that parasitize ascidians. We described the surface ultrastructure of two new gregarine species, L. chelyosomae sp. n. and L. cystodytae sp. n. that inhabit the intestines of Chelyosoma columbianum and Cystodytes lobatus, respectively, collected from the North‐eastern Pacific Ocean. Apart from inhabiting different hosts and major differences in the cell size of L. chelyosomae sp. n. (mean length 182 µm) and L. cystodytae sp. n. (mean length 70 µm), the morphology of both gregarine species was quite similar. The trophozoites ranged from elliptoid to obdeltoid in shape and were brownish in colour. The nucleus was situated at the anterior end of the cell just behind a pointed mucron. A dense array of epicytic knobs was present over the entire surface of trophozoites in both species, and longitudinal epicytical folds were only weakly developed. We also sequenced the small subunit rDNA from the gregarines collected from both hosts, which supported the establishment of two new Lankesteria species. Phylogenetic analyses of the new DNA sequences and those derived from other alveolates, demonstrated that both new species clustered in a strongly supported clade consisting of other Lankesteria species, Lecudina species, and some environmental sequences. These morphological and molecular phylogenetic data suggested that improved knowledge of gregarine diversity could lead to the recognition of more than one distinct clade (genus) of gregarines within ascidian hosts.
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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 | 0.000 |
| 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".