Possible causes of amphi-Atlantic distribution of Orchestia gammarellus (Pallas, 1776) (Crustacea, Amphipoda, Talitridae) in the North Atlantic: a review
Bibliographic record
Abstract
Hypotheses concerning the modern distribution of Orchestia gammarellus (Crustacea, Amphipoda, Talitridae) and its causes in the North Atlantic are discussed. The synanthropic dispersal hypothesis of Henzler and Ingólfsson (2008) considers O. gammarellus as originating on the eastern shore of the North Atlantic and being transported by humans to Iceland and the western Atlantic shore (Newfoundland and the Maritime Provinces of Canada). The Eocene and natural dispersal hypothesis of Myers and Lowry (2020) proposes a geologically earlier origin of O. gammarellus when the west and east shores of the North Atlantic were still connected. Present day amphi-Atlantic distribution was explained by vicariance, with the vicariant event causing separation of O. gammarellus being continental drift drawing apart the west and east shores of the North Atlantic. A post-glacial natural dispersal hypothesis proposed herein, involves transport on ice floes or in driftwood from European shores to Iceland and the Atlantic Provinces of Canada. The small genetic distances amongst populations found by Henzler and Ingólfsson (2008) at the COI gene are inconsistent with the Eocene vicariance hypothesis. On evolutionary grounds, we question Myers and Lowry’s (2020) designation of the Icelandic and Canadian populations as a new species of Orchestia . Existing molecular and morphological data are insufficient to distinguish between human-aided dispersal and natural rafting.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 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) | 0.000 | 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".