Molecular phylogeny of the genus Themisto (Guérin, 1925) (Amphipoda: Hyperiidae) in the Northern Hemisphere
Bibliographic record
Abstract
The Amphipoda is a highly speciose order of crustaceans with a life cycle characterized by direct development and no larval stage, making them interesting models for studies on marine speciation. The family Hyperiidae Dana, 1852 is a strictly pelagic group of Amphipoda. In northern latitudes, free-swimming hyperiids belonging to the genus Themisto (Guérin, 1825) are important components of marine ecosystems in term of abundance and biomass, but little is known about their genetic relationships. We present the first multi-locus molecular phylogenetic assessment of the Themisto in the Northern Hemisphere. We performed Bayesian and maximum likelihood reconstructions based on three nuclear loci (18S rDNA, 28S rDNA, and Histone 3) and mitochondrial cytochrome oxidase I data on eight specimens of Themisto from the Pacific, Arctic, and Atlantic oceans. We also provide an updated molecular phylogeny of Hyperiidae. Based on our multi-locus phylogeny, we report the presence of cryptic species in the North Pacific. Our results are discussed in the light of marine speciation.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 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".