Structure and phylogenetic significance of the sternum V glands in Trichoptera
Bibliographic record
Abstract
I investigated the sternum V gland in 38 families of Trichoptera, and found it to be present in 25 of these. I found that the gland is generally present in Annulipalpia, except Dipseudopsidae, and in Spicipalpia. It is widespread in Plenitentoria, while it is often absent in Brevitentoria, especially in males. The opening is slit-like and U or crescent-shaped. There is significant variation in the cuticular structures associated with the opening ranging from no apparent modification, over scaly patches to elaborate protuberances. Gland opening muscles are associated with the gland in all families except Psychomyiidae, and are divided into 2 distinct types: One originating on the front edge of sternum VI found in Philopotamidae, Rhyacophilidae, Glossosomatidae and Hydroptilidae; and 1 originating on the cuticle of sternum V found in all other trichopterans. The shape of the gland reservoir is variable, from round periform to reniform, elongate or compartmentalised. Muscle fibres are often associated with the reservoir, but are notably absent in Limnephilidae. I mapped characters based on gland structures on a phylogeny of Trichoptera, and discuss the results. The sternum V gland provides potentially important characters from the superorder to the species level. I discuss 2 cases where characters from the sternum V gland may solve existing phylogenetic and taxonomic puzzles: Delimitation of Dipseudopsidae versus Polycentropodidae and the relationships among the hydropsychid subfamilies.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| 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".