Are the western water shrew (<i>Sorex navigator</i>) and American water shrew (<i>Sorex palustris</i>) morphologically distinct?
Bibliographic record
Abstract
Recent phylogenetic studies applying the mitochondrial cytochrome b (Cytb) gene and nuclear genes revealed divergent cordilleran and boreal lineages in western populations of the Sorex palustris complex that are now recognized as distinct species: Sorex navigator (Baird, 1858) (western water shrew) and Sorex palustris Richardson, 1828 (American water shrew). Their distributions in western Canada are parapatric with a potential contact zone in the foothills of the Rocky Mountains. Using 80 specimens including 69 of known genotype, we assessed morphological differentiation in metric and nonmetric traits among S. navigator, S. palustris, and Sorex bendirii (Merriam, 1894) (marsh shrew), a sister species of S. navigator. Multivariate analyses revealed discrete morpho groups concordant with their genetic lineages and species-level divergence. Three individuals from northwestern British Columbia and one from southwestern Alberta with discordant mitochondrial and nuclear DNA aligned with the S. navigator morpho group showing no evidence for morphological intergradation with S. palustris. Although differentiated in genotype, S. navigator and S. palustris are cryptic species that can only be discriminated from morphology with metric cranio-dental data. We developed diagnostic morphometric criteria to identify specimens lacking genetic data.
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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 | 0.000 | 0.001 |
| 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".