Cenozoic Cichlids of Africa (Cichlidae: Pseudocrenilabrinae) With the Description of a New Species From the Oligocene of Somalia
Bibliographic record
Abstract
Cichlid fishes are an important component of the African freshwater ecosystem and the evolution of this group has captured the interest of ichthyologists for many decades. The distribution of cichlid fishes in both Africa and South America, and the apparent reciprocal monophyly of the cichlids in the two areas, has led to differences in opinion as to whether their modern distribution reflects a dispersal event from Africa to South America or was the result of a vicariant event–the break-up of the two continental masses in the mid-Cretaceous. If the vicariant event were the cause of the modern distribution, this would indicate an age for the family of at least 120 million years; however, the fossil record indicates a younger, Cenozoic, age for the family. The known fossil taxa in Africa often are difficult to assign to extant tribes which creates inaccuracies when they are used to date lineages within Cichlidae. The difficulty of assigning fossil cichlids to modern lineages is caused by most of these lineages being recognized based on DNA or soft-tissue characters, which are generally not preserved in fossils. This hampers our understanding of the early history of the family. Despite this, new African cichlid fossils that have been described in the past two decades and a new technique to determine relationships of these fossils are beginning to elucidate the early history of the family in Africa. Here the Palaeogene (Eocene and Oligocene) cichlids of Africa are reviewed and a new taxon from the Oligocene of Somalia, Somalichromis hadrocephalus gen. et sp. nov. is described.
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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 | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| 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".