Morphological and molecular analysis of Willowsia nigromaculata (Collembola, Entomobryidae, Entomobryinae) reveals a new cryptic species from the United States
Bibliographic record
Abstract
Commonly reported as a household pest throughout the northern hemisphere, Willowsia nigromaculata (Lubbock) is among the most abundant and widely distributed springtails. However, taxonomic uncertainty due to incomplete morphological descriptions based on specimens from different continents may lead to incorrect identifications and/or prevent the recognition of distinct lineages within this morphospecies. Here, we perform the first comprehensive morphological and genetic comparison between W. nigromaculata specimens collected from North America and Europe. Morphological and genetic evidence reveals that populations in the United States and France represent two distinct nigromaculata-like species, but a phylogenetic analysis indicates both species may also be present in Canada. Based on these results, we redescribe W. nigromaculata from France, provide a description for Willowsia neonigromaculata sp. nov. from the United States, and propose new diagnostic characters for their separation, including the number of inner appendages on the maxillary sublobal plate. We also highlight the need for morphological and molecular investigations of additional populations to better understand the diversity and distribution of W. nigromaculata and related species.
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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 | 0.000 |
| 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 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".