Revision of Lathonura rectirostris (O.F. Müller, 1785) (Anomopoda, Macrothricidae) leads to translocation of East Asian populations to a separate species, Lathonura bekkerae sp. nov.
Bibliographic record
Abstract
The family Macrothricidae (Branchiopoda: Anomopoda) remains one of the least studied groups of water fleas (Cladocera). One of macrothricids with an unclear phylogenetic status is Lathonura Lilljeborg, 1853 comprising a single universally accepted valid species, L. rectirostris (O.F. Müller, 1785). Despite its wide distribution in the Northern Hemisphere, no studies were conducted to prove conspecificity of L. rectirostris from different regions and properly describe its gamogenetic stages. Here, the morphological and genetic diversity of Lathonura in the Holarctic is revised. Our results show that in East Eurasia and Alaska a separate species of the genus occurs, L. bekkeraesp. nov., which differs from L. rectirostris s. str. by the posteroventral valve armature, structure of antenna I, and ephippium ornamentation. Mitochondrial DNA barcoding supports separation of L. bekkeraesp. nov. and reveals a deeply divergent clade of L. rectirostris s. l. in Canada, for which parthenogenetic females are morphologically indistinct from those of L. rectirostris s. str. Lathonura distribution fits well to the known patterns of Anomopoda biogeography. Males of Lathonura possess two additional setae at antenna II basipodite, P1 with a subdistal lobe lacking setae, P1 IDL with a hook and an additional seta, and an unmodified postabdomen. As noted in some previous studies, Lathonura likely represents a phylogenetic lineage distinct from the subfamily Macrothricinae, differing from most macrothricines by the absence of Fryer’s fork at P1 inner endite anterior setae and presence of P1 accessory seta. However, the phylogenetic position of the genus and its diversity in South Eurasia, Africa, and North America requires further studies.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".