Masked behind <i>Cnesterodon decemmaculatus</i> (Cyprinodontiformes: Poeciliidae): integrative taxonomy uncovers a new <i>Cnesterodon</i> species with broad ecological and biogeographic implications
Bibliographic record
Abstract
A new species of poeciliid, Cnesterodon pampeanus (Cyprinodontiformes), is described from Pampean streams, Argentina, based on integrative taxonomy. Generalised discriminant analysis of morphometric data allowed to discriminate the new species from its congeners, providing a reliable tool for an accurate identification of Cnesterodon species. Additionally, phylogenetic reconstructions of COI sequences revealed that the new species is grouped in a well-supported clade, validating the erection of a new Cnesterodon species. Up to the present, only Cnesterodon decemmaculatus (Jenyns, 1842) has been recorded inhabiting freshwater environments south of La Plata River, being considered one of the most widespread fish species in the Pampa biome. However, the geographic distribution of sequenced specimens, previously misidentified as Cnesterodon decemmaculatus, suggests that the newly described species actually has the southernmost distribution, having remained masked behind Cnesterodon decemmaculatus for years. The sympatric and syntopic presence of at least two species of Cnesterodon in the Pampas region implies that caution should be exercised when using Cnesterodon decemmaculatus to study processes that shape their genetic structure, since differences among populations can be overestimated if both species are considered as a single one. Additionally, differences in the morphology of Cnesterodon decemmaculatus previously attributed to the effect of pollutants may instead be interspecific variability.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| 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".