A “complex” problem: delimiting sibling species boundaries in black flies (Diptera: Simuliidae)
Bibliographic record
Abstract
Abstract Rapid and recent lineage radiations pose challenges to systematists. Using members of the highly diverseSimulium arcticumMalloch complex, we tested whether the cytochromecoxidase subunit I (COI) barcoding gene can differentiate black fly sibling species. Members of theS. arcticumcomplex were monophyletic in relation to two morphospecies and two cryptic species of theSimulium malyscheviDorogostaiskyet al.andSimulium noelleriFriederichs species-groups, respectively. Of fiveS. arcticumsibling species analysed, onlySimulium negativumAdleret al.was monophyletic. No other members of the complex could be distinguished using COI barcodes. The inability to resolveS. arcticumsibling species resulted because (1) haplotypes were shared between species and (2) the distribution of interspecific genetic distances completely overlapped the range of variation within species. Potential sources of incongruence between barcode data and species boundaries include imperfect taxonomy, inadequate genetic information, incomplete lineage sorting, and/or introgressive hybridization. We ruled out imperfect taxonomy because chromosomal, ecological, and distributional evidence support the validity ofS. arcticumsibling species. Therefore, current nomenclature should be maintained pending further study. We conclude that one or more of the latter three sources of incongruence could be responsible for the lack of reciprocal monophyly among species of theS. arcticumcomplex.
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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 | 0.004 | 0.011 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.002 | 0.002 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.001 | 0.002 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".