Data from: Pleistocene transitions from the proto-Congo to adjacent rivers uncovered by phylogenetics and biogeography of <em>Bryconaethiops</em> (Teleostei: Alestidae)
Bibliographic record
Abstract
African freshwater fishes serve as important biogeographical indicators of geomorphological and hydrological history across the continent. However, research focusing on the phylogeny, biogeography, and diversification of African fishes, particularly in central Africa, is relatively scarce. Here, we evaluate three geological hypotheses regarding the formation of the contemporary Congo basin: 1) the dominance of the Ogooué and Kouilou rivers along the western continental margin during the Cretaceous, 2) an eastward-flowing Congo-Zambezian system forming the Rufiji Delta during the Paleogene, and 3) river basin capture resulting in the formation of the Lower Congo River during the Pliocene. To do this, we reconstructed the phylogeny of featherfin tetras of the genus Bryconaethiops using their mitochondrial genomes, estimated diversification chronology, and detected biogeographic transitions in Central Africa. Analysis included a molecular matrix of complete mitochondrial genomes comprising 13 protein-coding genes totaling 14,869 bp for 36 Bryconaethiops and related alestid taxa. Phylogenetic analyses included maximum likelihood, Bayesian fossil calibration, and parametric biogeographic reconstructions. Support for generic monophyly was evaluated using internal and external anatomy with microcomputed tomography (µCT) and conventional morphometric/meristic analyses. Data from museum specimens provided updated distributional ranges for each Bryconaethiops species. Time-calibrated phylogenetic and biogeographic analyses suggest initial diversification of Bryconaethiops occurred in Lower Guinea during the Oligocene (ca. 25 Ma), followed by transitions to the Nilo-Sudan and Middle Congo regions during the Early Miocene (ca. 19–17 Ma). Three distinct Pleistocene dispersal events to the Lower Congo (ca. 0.7–0.05 Ma) and three to the Upper Congo and Malagarasi of Tanganyika (ca. 1.5–0.1 Ma) were detected. Morphological analysis reveals four generic synapomorphies associated with modification of the upper and lower jaws, dentition, and elongation of dorsal-fin lepidotrichia, in addition to evidence for revalidation of B. mocquardianus (Thominot, 1886) from Atlantic coastal rivers of the eastern Gulf of Guinea.
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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 | 0.001 | 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) | 0.002 | 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".