Integrative Analysis of Retusa pertenuis (Heterobranchia: Cephalaspidea) from Arctic and Russian Far East Seas with Discussion of Its Morphology, Validity and Population Structure
Bibliographic record
Abstract
Retusa pertenuis is still formally considered a junior subjective synonym of Retusa obtusa, despite previous data indicating R. pertenuis and R. obtusa differ significantly in copulatory system morphology. In this paper, we study the species identity and population structure of R. pertenuis with an integrative approach combining morphological and molecular data. The external morphology, head copulatory system and gizzard plates were studied using light microscopy and scanning electron microscopy. We also obtained two mitochondrial (COI and 16S) and two nuclear (H3 and 28S) markers to test the monophyly of R. pertenuis and R. obtusa. Populations from the White Sea, Sea of Okhotsk and Sea of Japan were studied using COI and 18S molecular markers. Our results show that Retusa obtusa sensu lato represents a species complex of at least four species: the nominative species occurring in the North Atlantic, the widely distributed R. pertenuis and two additional species whose identities should be clarified in further studies. Retusa pertenuis geographic range encompasses the North Atlantic, Eurasia’s northern seas, the Canadian Arctic, the Bering Sea, the Sea of Okhotsk and the Sea of Japan. Within R. pertenuis’s range, this species demonstrates a wide variability in shell morphology.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 teacher head, 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".