Aquatic Biotas of Sundaland Are Fragmented But Not Refugial
Bibliographic record
Abstract
Tropical insular systems have long attracted biologists, stimulating some important controversies in ecology and evolution. Eustatic fluctuations during the Pleistocene have been invoked to explain species dispersal and proliferation in these fragmented systems by controlling the extent of landmasses and their temporary connections. In ancient archipelagos, the Pleistocene represents only a small slice of their history, so long-standing configurations might better explain insular diversity patterns. With a geological history of ca. 30 million years, the Sunda Shelf is old. Upon entering the Pleistocene, islands of the Sunda Shelf repeatedly separated and merged; however, recent reappraisals of its paleoenvironments and evolutionary dynamics have questioned their biogeographic significance. Based on the molecular inventory of 6 common freshwater fish families, we explored population fragmentation and demographic history of the most common species using mitochondrial DNA sequences. Species delimitation methods, applied to 1062 sequences belonging to 37 species from 188 sites, detected 95 Molecular Operational Taxonomic Units (MOTUs). Among the 9 most widespread species, the number of MOTUs ranged from 1 to 11, and correlated with time to the most recent common ancestor. Extended Bayesian Skyline Plots applied to mitogenomes and cytochrome c oxidase I sequences detected no variation in past effective population size within MOTUs, while hierarchical Approximate Bayesian Computation provided no evidence of congruent changes in effective population sizes. Fragmentation of an ancestral range is the most likely explanation for the rampant cryptic diversity observed, but demographic inferences do not support MOTUs as being refugial from an evolutionary perspective.
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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 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".